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Plumb AA, Pathiraja F, Nickerson C, Wooldrage K, Burling D, Taylor SA, Atkin WS, Halligan S. Appearances of screen-detected versus symptomatic colorectal cancers at CT colonography. Eur Radiol 2016; 26:4313-4322. [PMID: 27048534 PMCID: PMC5101282 DOI: 10.1007/s00330-016-4293-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 12/29/2015] [Accepted: 02/18/2016] [Indexed: 12/11/2022]
Abstract
OBJECTIVES The aim of this study was to compare the morphology, radiological stage, conspicuity, and computer-assisted detection (CAD) characteristics of colorectal cancers (CRC) detected by computed tomographic colonography (CTC) in screening and symptomatic populations. METHODS Two radiologists independently analyzed CTC images from 133 patients diagnosed with CRC in (a) two randomized trials of symptomatic patients (35 patients with 36 tumours) and (b) a screening program using fecal occult blood testing (FOBt; 98 patients with 100 tumours), measuring tumour length, volume, morphology, radiological stage, and subjective conspicuity. A commercial CAD package was applied to both datasets. We compared CTC characteristics between screening and symptomatic populations with multivariable regression. RESULTS Screen-detected CRC were significantly smaller (mean 3.0 vs 4.3 cm, p < 0.001), of lower volume (median 9.1 vs 23.2 cm3, p < 0.001) and more frequently polypoid (34/100, 34 % vs. 5/36, 13.9 %, p = 0.02) than symptomatic CRC. They were of earlier stage than symptomatic tumours (OR = 0.17, 95 %CI 0.07-0.41, p < 0.001), and were judged as significantly less conspicuous (mean conspicuity 54.1/100 vs. 72.8/100, p < 0.001). CAD detection was significantly lower for screen-detected (77.4 %; 95 %CI 67.9-84.7 %) than symptomatic CRC (96.9 %; 95 %CI 83.8-99.4 %, p = 0.02). CONCLUSIONS Screen-detected CRC are significantly smaller, more frequently polypoid, subjectively less conspicuous, and less likely to be identified by CAD than those in symptomatic patients. KEY POINTS • Screen-detected colorectal cancers (CRC) are significantly smaller than symptomatic CRC. • Screening cases are significantly less conspicuous to radiologists than symptomatic tumours. • Screen-detected CRC have different morphology compared to symptomatic tumours (more polypoid, fewer annular). • A commercial computer-aided detection (CAD) system was significantly less likely to note screen-detected CRC.
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Affiliation(s)
- Andrew A Plumb
- Centre for Medical Imaging, University College London, London, UK
| | - Fiona Pathiraja
- Centre for Medical Imaging, University College London, London, UK
| | | | | | - David Burling
- Intestinal Imaging Centre, St Mark's Hospital, Harrow, UK
| | - Stuart A Taylor
- Centre for Medical Imaging, University College London, London, UK
| | - Wendy S Atkin
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Steve Halligan
- Centre for Medical Imaging, University College London, London, UK.
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Halligan S, Dadswell E, Wooldrage K, Wardle J, von Wagner C, Lilford R, Yao GL, Zhu S, Atkin W. Computed tomographic colonography compared with colonoscopy or barium enema for diagnosis of colorectal cancer in older symptomatic patients: two multicentre randomised trials with economic evaluation (the SIGGAR trials). Health Technol Assess 2015; 19:1-134. [PMID: 26198205 PMCID: PMC4781284 DOI: 10.3310/hta19540] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Computed tomographic colonography (CTC) is a relatively new diagnostic test that may be superior to existing alternatives to investigate the large bowel. OBJECTIVES To compare the diagnostic efficacy, acceptability, safety and cost-effectiveness of CTC with barium enema (BE) or colonoscopy. DESIGN Parallel randomised trials: BE compared with CTC and colonoscopy compared with CTC (randomisation 2 : 1, respectively). SETTING A total of 21 NHS hospitals. PARTICIPANTS Patients aged ≥ 55 years with symptoms suggestive of colorectal cancer (CRC). INTERVENTIONS CTC, BE and colonoscopy. MAIN OUTCOME MEASURES For the trial of CTC compared with BE, the primary outcome was the detection rate of CRC and large polyps (≥ 10 mm), with the proportion of patients referred for additional colonic investigation as a secondary outcome. For the trial of CTC compared with colonoscopy, the primary outcome was the proportion of patients referred for additional colonic investigation, with the detection rate of CRC and large polyps as a secondary outcome. Secondary outcomes for both trials were miss rates for cancer (via registry data), all-cause mortality, serious adverse events, patient acceptability, extracolonic pathology and cost-effectiveness. RESULTS A total of 8484 patients were registered and 5384 were randomised and analysed (BE trial: 2527 BE, 1277 CTC; colonoscopy trial: 1047 colonoscopy, 533 CTC). Detection rates in the BE trial were 7.3% (93/1277) for CTC, compared with 5.6% (141/2527) for BE (p = 0.0390). The difference was due to better detection of large polyps by CTC (3.6% vs. 2.2%; p = 0.0098), with no significant difference for cancer (3.7% vs. 3.4%; p = 0.66). Significantly more patients having CTC underwent additional investigation (23.5% vs. 18.3%; p = 0.0003). At the 3-year follow-up, the miss rate for CRC was 6.7% for CTC (three missed cancers) and 14.1% for BE (12 missed cancers). Significantly more patients randomised to CTC than to colonoscopy underwent additional investigation (30% vs. 8.2%; p < 0.0001). There was no significant difference in detection rates for cancer or large polyps (10.7% for CTC vs. 11.4% for colonoscopy; p = 0.69), with no difference when cancers (p = 0.94) and large polyps (p = 0.53) were analysed separately. At the 3-year follow-up, the miss rate for cancer was nil for colonoscopy and 3.4% for CTC (one missed cancer). Adverse events were uncommon for all procedures. In 1042 of 1748 (59.6%) CTC examinations, at least one extracolonic finding was reported, and this proportion increased with age (p < 0.0001). A total of 149 patients (8.5%) were subsequently investigated, and extracolonic neoplasia was diagnosed in 79 patients (4.5%) and malignancy in 29 (1.7%). In the short term, CTC was significantly more acceptable to patients than BE or colonoscopy. Total costs for CTC and colonoscopy were finely balanced, but CTC was associated with higher health-care costs than BE. The cost per large polyp or cancer detected was £4235 (95% confidence interval £395 to £9656). CONCLUSIONS CTC is superior to BE for detection of cancers and large polyps in symptomatic patients. CTC and colonoscopy detect a similar proportion of large polyps and cancers and their costs are also similar. CTC precipitates significantly more additional investigations than either BE or colonoscopy, and evidence-based referral criteria are needed. Further work is recommended to clarify the extent to which patients initially referred for colonoscopy or BE undergo subsequent abdominopelvic imaging, for example by computed tomography, which will have a significant impact on health economic estimates. TRIAL REGISTRATION Current Controlled Trials ISRCTN95152621.
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Affiliation(s)
- Steve Halligan
- Centre for Medical Imaging, University College London, London, UK
| | - Edward Dadswell
- Cancer Screening and Prevention Research Group, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Kate Wooldrage
- Cancer Screening and Prevention Research Group, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Jane Wardle
- Health Behaviour Research Centre, Department of Epidemiology and Public Health, University College London, London, UK
| | - Christian von Wagner
- Health Behaviour Research Centre, Department of Epidemiology and Public Health, University College London, London, UK
| | - Richard Lilford
- School of Health and Population Sciences, University of Birmingham, Birmingham, UK
- Population Evidence and Technologies, University of Warwick, Warwick, UK
| | - Guiqing L Yao
- School of Health and Population Sciences, University of Birmingham, Birmingham, UK
- Primary Care and Population Sciences, University of Southampton, Southampton, UK
| | - Shihua Zhu
- School of Health and Population Sciences, University of Birmingham, Birmingham, UK
| | - Wendy Atkin
- Cancer Screening and Prevention Research Group, Department of Surgery and Cancer, Imperial College London, London, UK
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Halligan S, Wooldrage K, Dadswell E, Shah U, Kralj-Hans I, von Wagner C, Faiz O, Teare J, Edwards R, Kay C, Yao G, Lilford RJ, Morton D, Wardle J, Atkin W. Identification of Extracolonic Pathologies by Computed Tomographic Colonography in Colorectal Cancer Symptomatic Patients. Gastroenterology 2015; 149:89-101.e5. [PMID: 25796362 DOI: 10.1053/j.gastro.2015.03.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 02/12/2015] [Accepted: 03/06/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND & AIMS Symptoms suggestive of colorectal cancer may originate outside the colorectum. Computed tomographic colonography (CTC) is used to examine the colorectum and abdominopelvic organs simultaneously. We performed a prospective randomized controlled trial to quantify the frequency, nature, and consequences of extracolonic findings. METHODS We studied 5384 patients from 21 UK National Health Service hospitals referred by their family doctor for the investigation of colorectal cancer symptoms from March 2004 through December 2007. The patients were assigned randomly to groups that received the requested test (barium enema or colonoscopy, n = 3574) or CTC (n = 1810). We determined the frequency and nature of extracolonic findings, subsequent investigations, ultimate diagnosis, and extracolonic cancer diagnoses 1 and 3 years after testing patients without colorectal cancer. RESULTS Extracolonic pathologies were detected in 959 patients by CTC (58.7%), in 42 patients by barium enema analysis (1.9%), and in no patients by colonoscopy. Extracolonic findings were investigated in 142 patients (14.2%) and a diagnosis was made for 126 patients (88.1%). Symptoms were explained by extracolonic findings in 4 patients analyzed by barium enema (0.2%) and in 33 patients analyzed by CTC (2.8%). CTC identified 72 extracolonic neoplasms, however, barium enema analysis found only 3 (colonoscopy found none). Overall, CTC diagnosed extracolonic neoplasms in 72 of 1634 patients (4.4%); 26 of these were malignant (1.6%). There were significantly more extracolonic malignancies detected than expected 1 year after examination, but these did not differ between patients evaluated by CTC (22.2/1000 person-years), barium enema (26.5/1000 person-years; P = .43), or colonoscopy (32.0/1000 person-years; P = .88). CONCLUSIONS More than half of the patients with symptoms of colorectal cancer are found to have extracolonic pathologies by CTC analysis. However, the proportion of patients found to have extracolonic malignancies after 1 year of CTC examination is not significantly greater than after barium enema or colonoscopy examinations. International Standard Randomised Controlled Trials no: 95152621.isrctn.com.
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Affiliation(s)
| | | | | | - Urvi Shah
- Imperial College London, London, United Kingdom
| | | | | | - Omar Faiz
- Imperial College London, London, United Kingdom
| | | | - Rob Edwards
- Queen Mary University of London, London, United Kingdom
| | - Clive Kay
- Bradford Teaching Hospitals National Health Service Foundation Trust, Bradford, United Kingdom
| | - Guiqing Yao
- University of Southampton, Southampton, United Kingdom
| | | | - Dion Morton
- University of Birmingham, Birmingham, United Kingdom
| | - Jane Wardle
- University College London, London, United Kingdom
| | - Wendy Atkin
- Imperial College London, London, United Kingdom
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He Q, Rao T, Guan YS. Virtual gastrointestinal colonoscopy in combination with large bowel endoscopy: Clinical application. World J Gastroenterol 2014; 20:13820-13832. [PMID: 25320519 PMCID: PMC4194565 DOI: 10.3748/wjg.v20.i38.13820] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/11/2014] [Accepted: 07/16/2014] [Indexed: 02/06/2023] Open
Abstract
Although colorectal cancer (CRC) has no longer been the leading cancer killer worldwide for years with the exponential development in computed tomography (CT) or magnetic resonance imaging, and positron emission tomography/CT as well as virtual colonoscopy for early detection, the CRC related mortality is still high. The objective of CRC screening is to reduce the burden of CRC and thereby the morbidity and mortality rates of the disease. It is believed that this goal can be achieved by regularly screening the average-risk population, enabling the detection of cancer at early, curable stages, and polyps before they become cancerous. Large-scale screening with multimodality imaging approaches plays an important role in reaching that goal to detect polyps, Crohn’s disease, ulcerative colitis and CRC in early stage. This article reviews kinds of presentative imaging procedures for various screening options and updates detecting, staging and re-staging of CRC patients for determining the optimal therapeutic method and forecasting the risk of CRC recurrence and the overall prognosis. The combination use of virtual colonoscopy and conventional endoscopy, advantages and limitations of these modalities are also discussed.
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Badiani S, Tomas-Hernandez S, Karandikar S, Roy-Choudhury S. Extracolonic findings (ECF) on CT colonography (CTC) in patients presenting with colorectal symptoms. Acta Radiol 2013; 54:851-62. [PMID: 23761550 DOI: 10.1177/0284185113486371] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Computed tomographic colonography (CTC) is now an established method for imaging the colon and rectum in the screening and symptomatic setting. Additional benefit of CTC is the ability to assess for extracolonic findings especially in patients presenting with colorectal symptoms. PURPOSE To determine prevalence of extracolonic findings (ECF) in symptomatic patients undergoing CTC and determine accuracy of CTC for exclusion of significant abdominal disease and extracolonic malignancy (ECM). MATERIAL AND METHODS A total of 1359 unenhanced prone and postcontrast supine CTC studies were performed between March 2002 and December 2007. ECF were retrospectively classified according to C-RADS criteria into E1 to E4 findings. For ECM, a gold standard of clinical and/or radiological follow-up supplemented with data from the regional cancer registry with a median follow-up of 42 months was created. Sensitivity and negative predictive values for ECM was calculated. RESULTS Following exclusions, 1177 CTCs were analyzed. Of 1423 extracolonic findings reported, 328/1423 (23%) E3 and 100/1423 (7%) E4 (including six eventual FP studies) findings were identified. Thirty-two ECMs were confirmed following further investigations. Seven further small ECMs were detected during the entire follow-up, of which two were potentially visible in retrospect (false-negative studies). Additional tests were generated from 55/1177 (4.7%) studies. Sensitivity and negative predictive value for ECM was 94.1% (95% CI 78.9-98.9%) and 99.8% (95% CI 99.3-99.9%), respectively. CONCLUSION One in 37 patients were found to have an ECM. Two potentially detectable cancers were missed. Only a small proportion of patients underwent additional work-up.
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Halligan S, Atkin W. CT colonography for diagnosis of symptomatic colorectal cancer: The SIGGAR trials and their implication for service delivery. Clin Radiol 2013; 68:643-5. [DOI: 10.1016/j.crad.2013.02.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 02/19/2013] [Indexed: 01/22/2023]
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Halligan S. CT colonography for investigation of patients with symptoms potentially suggestive of colorectal cancer: a review of the UK SIGGAR trials. Br J Radiol 2013; 86:20130137. [PMID: 23568360 DOI: 10.1259/bjr.20130137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
This paper argues for the use of CT colonography (CTC) to investigate patients with symptoms potentially suggestive of colorectal cancer. It describes the rationale for the UK Special Interest Group in Gastrointestinal and Abdominal Radiology (SIGGAR) randomised controlled trials that compared CTC with barium enema (BE) or colonoscopy for diagnosis of colorectal cancer or large polyps in symptomatic patients. Diagnostic outcomes from the trials are detailed for both intra- and extracolonic disease, along with psychological reactions of patients to the tests, and cost-effectiveness of the different diagnostic strategies. The author concludes that BE should be replaced by CTC immediately and that CTC is a sensitive, acceptable and equally cost-effective alternative to colonoscopy in patients in whom colonoscopy is contraindicated or undesirable.
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Affiliation(s)
- S Halligan
- Centre for Medical Imaging, University College London, London, UK.
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Halligan S, Wooldrage K, Dadswell E, Kralj-Hans I, von Wagner C, Edwards R, Yao G, Kay C, Burling D, Faiz O, Teare J, Lilford RJ, Morton D, Wardle J, Atkin W. Computed tomographic colonography versus barium enema for diagnosis of colorectal cancer or large polyps in symptomatic patients (SIGGAR): a multicentre randomised trial. Lancet 2013; 381:1185-93. [PMID: 23414648 DOI: 10.1016/s0140-6736(12)62124-2] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Barium enema (BE) is widely available for diagnosis of colorectal cancer despite concerns about its accuracy and acceptability. Computed tomographic colonography (CTC) might be a more sensitive and acceptable alternative. We aimed to compare CTC and BE for diagnosis of colorectal cancer or large polyps in symptomatic patients in clinical practice. METHODS This pragmatic multicentre randomised trial recruited patients with symptoms suggestive of colorectal cancer from 21 UK hospitals. Eligible patients were aged 55 years or older and regarded by their referring clinician as suitable for radiological investigation of the colon. Patients were randomly assigned (2:1) to BE or CTC by computer-generated random numbers, in blocks of six, stratified by trial centre and sex. We analysed the primary outcome-diagnosis of colorectal cancer or large (≥10 mm) polyps-by intention to treat. The trial is an International Standard Randomised Controlled Trial, number 95152621. FINDINGS 3838 patients were randomly assigned to receive either BE (n=2553) or CTC (n=1285). 34 patients withdrew consent, leaving for analysis 2527 assigned to BE and 1277 assigned to CTC. The detection rate of colorectal cancer or large polyps was significantly higher in patients assigned to CTC than in those assigned to BE (93 [7.3%] of 1277 vs 141 [5.6%] of 2527, relative risk 1.31, 95% CI 1.01-1.68; p=0.0390). CTC missed three of 45 colorectal cancers and BE missed 12 of 85. The rate of additional colonic investigation was higher after CTC than after BE (283 [23.5%] of 1206 CTC patients had additional investigation vs 422 [18.3%] of 2300 BE patients; p=0.0003), due mainly to a higher polyp detection rate. Serious adverse events were rare. INTERPRETATION CTC is a more sensitive test than BE. Our results suggest that CTC should be the preferred radiological test for patients with symptoms suggestive of colorectal cancer. FUNDING NIHR Health Technology Assessment Programme, NIHR Biomedical Research Centres funding scheme, Cancer Research UK, EPSRC Multidisciplinary Assessment of Technology Centre for Healthcare, and NIHR Collaborations for Leadership in Applied Health Research and Care.
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Affiliation(s)
- Steve Halligan
- University College London, Centre for Medical Imaging, Podium Level 2, 235 Euston Road, London NW1 2BU, UK.
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Atkin W, Dadswell E, Wooldrage K, Kralj-Hans I, von Wagner C, Edwards R, Yao G, Kay C, Burling D, Faiz O, Teare J, Lilford RJ, Morton D, Wardle J, Halligan S. Computed tomographic colonography versus colonoscopy for investigation of patients with symptoms suggestive of colorectal cancer (SIGGAR): a multicentre randomised trial. Lancet 2013; 381:1194-202. [PMID: 23414650 DOI: 10.1016/s0140-6736(12)62186-2] [Citation(s) in RCA: 188] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Colonoscopy is the gold-standard test for investigation of symptoms suggestive of colorectal cancer; computed tomographic colonography (CTC) is an alternative, less invasive test. However, additional investigation after CTC is needed to confirm suspected colonic lesions, and this is an important factor in establishing the feasibility of CTC as an alternative to colonoscopy. We aimed to compare rates of additional colonic investigation after CTC or colonoscopy for detection of colorectal cancer or large (≥10 mm) polyps in symptomatic patients in clinical practice. METHODS This pragmatic multicentre randomised trial recruited patients with symptoms suggestive of colorectal cancer from 21 UK hospitals. Eligible patients were aged 55 years or older and regarded by their referring clinician as suitable for colonoscopy. Patients were randomly assigned (2:1) to colonoscopy or CTC by computer-generated random numbers, in blocks of six, stratified by trial centre and sex. We analysed the primary outcome-the rate of additional colonic investigation-by intention to treat. The trial is an International Standard Randomised Controlled Trial, number 95152621. FINDINGS 1610 patients were randomly assigned to receive either colonoscopy (n=1072) or CTC (n=538). 30 patients withdrew consent, leaving for analysis 1047 assigned to colonoscopy and 533 assigned to CTC. 160 (30.0%) patients in the CTC group had additional colonic investigation compared with 86 (8.2%) in the colonoscopy group (relative risk 3.65, 95% CI 2.87-4.65; p<0.0001). Almost half the referrals after CTC were for small (<10 mm) polyps or clinical uncertainty, with low predictive value for large polyps or cancer. Detection rates of colorectal cancer or large polyps in the trial cohort were 11% for both procedures. CTC missed 1 of 29 colorectal cancers and colonoscopy missed none (of 55). Serious adverse events were rare. INTERPRETATION Guidelines are needed to reduce the referral rate after CTC. For most patients, however, CTC provides a similarly sensitive, less invasive alternative to colonoscopy. FUNDING NIHR Health Technology Assessment Programme, NIHR Biomedical Research Centres funding scheme, Cancer Research UK, EPSRC Multidisciplinary Assessment of Technology Centre for Healthcare, and NIHR Collaborations for Leadership in Applied Health Research and Care.
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Affiliation(s)
- Wendy Atkin
- Cancer Screening and Prevention Research Group, Imperial College London, St Mary's Hospital, Norfolk Place, London W2 1PG, UK.
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Diagnosis: CT colonography has finally arrived. Nat Rev Clin Oncol 2013; 10:254-5. [PMID: 23546516 DOI: 10.1038/nrclinonc.2013.54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Gomes M, Aldridge RW, Wylie P, Bell J, Epstein O. Cost-effectiveness analysis of 3-D computerized tomography colonography versus optical colonoscopy for imaging symptomatic gastroenterology patients. APPLIED HEALTH ECONOMICS AND HEALTH POLICY 2013; 11:107-117. [PMID: 23512599 DOI: 10.1007/s40258-013-0019-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND When symptomatic gastroenterology patients have an indication for colonic imaging, clinicians have a choice between optical colonoscopy (OC) and computerized tomography colonography with three-dimensional reconstruction (3-D CTC). 3-D CTC provides a minimally invasive and rapid evaluation of the entire colon, and it can be an efficient modality for diagnosing symptoms. It allows for a more targeted use of OC, which is associated with a higher risk of major adverse events and higher procedural costs. A case can be made for 3-D CTC as a primary test for colonic imaging followed if necessary by targeted therapeutic OC; however, the relative long-term costs and benefits of introducing 3-D CTC as a first-line investigation are unknown. AIM The aim of this study was to assess the cost effectiveness of 3-D CTC versus OC for colonic imaging of symptomatic gastroenterology patients in the UK NHS. METHODS We used a Markov model to follow a cohort of 100,000 symptomatic gastroenterology patients, aged 50 years or older, and estimate the expected lifetime outcomes, life years (LYs) and quality-adjusted life years (QALYs), and costs (£, 2010-2011) associated with 3-D CTC and OC. Sensitivity analyses were performed to assess the robustness of the base-case cost-effectiveness results to variation in input parameters and methodological assumptions. RESULTS 3D-CTC provided a similar number of LYs (7.737 vs 7.739) and QALYs (7.013 vs 7.018) per individual compared with OC, and it was associated with substantially lower mean costs per patient (£467 vs £583), leading to a positive incremental net benefit. After accounting for the overall uncertainty, the probability of 3-D CTC being cost effective was around 60 %, at typical willingness-to-pay values of £20,000-£30,000 per QALY gained. CONCLUSION 3-D CTC is a cost-saving and cost-effective option for colonic imaging of symptomatic gastroenterology patients compared with OC.
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Affiliation(s)
- Manuel Gomes
- Department of Health Services Research and Policy, London School of Hygiene and Tropical Medicine, 15-17 Tavistock Place, London WC1H 9SH, UK.
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Kahi CJ, Anderson JC, Rex DK. Screening and surveillance for colorectal cancer: state of the art. Gastrointest Endosc 2013; 77:335-50. [PMID: 23410695 DOI: 10.1016/j.gie.2013.01.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 01/01/2013] [Indexed: 12/11/2022]
Affiliation(s)
- Charles J Kahi
- Department of Medicine, Division of Gastroenterology and Hepatology, Indiana University School of Medicine, Indianapolis, IN, USA
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Abstract
PURPOSE OF REVIEW Computed tomography colonography (CTC) continues to mature and evolve as a noninvasive imaging test of the large intestine. The aim of this review is to provide an update on the recent and emerging data that further supports the clinical effectiveness of CTC. RECENT FINDINGS The diagnostic performance of CTC for detecting colorectal polyps and masses is well established, but its precise clinical role is yet to be determined. Recent data on test performance, patient acceptance, and study technique may help to clarify the role of CTC and accelerate its clinical implementation. SUMMARY Recent advances and refinements in CTC should help to clarify and expand its clinical role, both as a screening and diagnostic test. High patient acceptance for CTC could lead to increased adherence rates. Ultimately, the complementary nature of CTC and optical colonoscopy should result in improved patient care.
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Plumb AA, Halligan S, Taylor SA, Burling D, Nickerson C, Patnick J. CT colonography in the English Bowel Cancer Screening Programme: national survey of current practice. Clin Radiol 2012; 68:479-87. [PMID: 23245277 DOI: 10.1016/j.crad.2012.10.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 10/26/2012] [Indexed: 10/27/2022]
Abstract
AIM To obtain information regarding the provision of computed tomography colonography (CTC) services to the National Health Service (NHS) Bowel Cancer Screening Programme (BCSP). MATERIALS AND METHODS Specialist screening practitioners at the 58 BCSP screening centres and lead BCSP radiologists at 110 hospitals performing CTC for the Programme were contacted and completed a semi-structured questionnaire administered by telephone. Responses were collated and descriptive statistics derived. RESULTS One hundred and seven (98%) SSPs and 103 (94%) radiologists were surveyed. All screening centres had access to CTC at 110 hospital sites. All sites used CTC for failed or contraindicated colonoscopy, 24% used it for patients taking anticoagulants, and 17% for those with fear of colonoscopy. Patient preference was not an indication at any site. Multidetector CT (100%), carbon dioxide insufflators (94%), and CTC software (95%) were almost universal. Ninety-one percent of radiographers and 98% of radiologists were trained in CTC image acquisition and interpretation, respectively. Seventy-five percent of the radiologists were gastrointestinal subspecialists and two-thirds had interpreted more than 300 examinations in clinical practice, although 5% had interpreted fewer than 100. Eighty-one percent of radiologists favoured some form of accreditation for CTC interpretation. CONCLUSIONS CTC is widely available to the BCSP. Appropriate hardware and software is almost ubiquitous. Most radiographers and radiologists offering CTC to the BCSP have received specific training. Formal service evaluation is patchy. The majority of radiologists would welcome national accreditation for CTC.
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Affiliation(s)
- A A Plumb
- Centre for Medical Imaging, Division of Medicine, University College London, UK
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Laghi A, Rengo M, Graser A, Iafrate F. Current status on performance of CT colonography and clinical indications. Eur J Radiol 2012; 82:1192-200. [PMID: 22749108 DOI: 10.1016/j.ejrad.2012.05.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 05/23/2012] [Indexed: 02/07/2023]
Abstract
CT colonography (CTC) is a robust and reliable imaging test of the colon. Accuracy for the detection of colorectal cancer (CRC) is as high as conventional colonoscopy (CC). Identification of polyp is size dependent, with large lesions (≥10mm) accurately detected and small lesions (6-9mm) identified with moderate to good sensitivity. Recent studies show good sensitivity for the identification of nonpolypoid (flat) lesions as well. Current CTC indications include the evaluation of patients who had undergone a previous incomplete CC or those who are unfit for CC (elderly and frail individuals, patients with underlying severe clinical conditions, or with contraindication to sedation). CTC can also be efficiently used in the assessment of diverticular disease (excluding patients with acute diverticulitis, where the exam should be postponed), before laparoscopic surgery for CRC (to have an accurate localization of the lesion), in the evaluation of colonic involvement in the case of deep pelvic endometriosis (replacing barium enema). CTC is also a safe procedure in patients with colostomy. For CRC screening, CTC should be considered an opportunistic screening test (not available for population, or mass screening) to be offered to asymptomatic average-risk individuals, of both genders, starting at age 50. The use in individuals with positive family history should be discussed with the patient first. Absolute contraindication is to propose CTC for surveillance of genetic syndromes and chronic inflammatory bowel diseases (in particular, ulcerative colitis). The use of CTC in the follow-up after surgery for CRC is achieving interesting evidences despite the fact that literature data are still relatively weak in terms of numerosity of the studied populations. In patients who underwent previous polypectomy CTC cannot be recommended as first test because debate is still open. It is desirable that in the future CTC would be the first-line and only diagnostic test for colonic diseases, leaving to CC only a therapeutic role.
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Affiliation(s)
- Andrea Laghi
- Department of Radiological Sciences, Oncology and Pathology Sapienza - Università di Roma, Polo Pontino, I.C.O.T. Hospital, Via Franco Faggiana 43, 04100 Latina, Italy.
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von Wagner C, Ghanouni A, Halligan S, Smith S, Dadswell E, Lilford RJ, Morton D, Atkin W, Wardle J. Patient acceptability and psychologic consequences of CT colonography compared with those of colonoscopy: results from a multicenter randomized controlled trial of symptomatic patients. Radiology 2012; 263:723-31. [PMID: 22438366 DOI: 10.1148/radiol.12111523] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE To use a randomized design to compare patients' short- and longer-term experiences after computed tomographic (CT) colonography or colonoscopy. MATERIALS AND METHODS After ethical approval, the trial was registered. Patients gave written informed consent. Five hundred forty-seven patients with symptoms suggestive of colorectal cancer who had been randomly assigned at a ratio of 2:1 to undergo either colonoscopy (n = 362) or CT colonography (n = 185) received a validated questionnaire to assess immediate test experience (including satisfaction, worry, discomfort, adverse effects) and a 3-month questionnaire to assess psychologic outcomes (including satisfaction with result dissemination and reassurance). Data were analyzed by using Mann-Whitney U, Kruskal-Wallis, and χ(2) test statistics. RESULTS Patients undergoing colonoscopy were less satisfied than those undergoing CT colonography (median score of 61 and interquartile range [IQR] of 55-67 vs median score of 64 and IQR of 58-70, respectively; P = .008) and significantly more worried (median score of 16 [IQR, 12-21] vs 15 [IQR, 9-19], P = .007); they also experienced more physical discomfort (median score of 39 [IQR, 29-51] vs 35 [IQR, 24-44]) and more adverse events (82 of 246 vs 28 of 122 reported feeling faint or dizzy, P = .039). However, at 3 months, they were more satisfied with how results were received (median score of 4 [IQR, 3-4] vs 3 [IQR, 3-3], P < .0005) and less likely to require follow-up colonic investigations (17 of 230 vs 37 of 107, P < .0005). No differences were observed between the tests regarding 3-month psychologic consequences of the diagnostic episode, except for a trend toward a difference (P = .050) in negative affect (unpleasant emotions such as distress), with patients undergoing CT colonography reporting less intense negative affect. CONCLUSION CT colonography has superior patient acceptability compared with colonoscopy in the short term, but colonoscopy offers some benefits to patients that become apparent after longer-term follow-up. The respective advantages of each test should be balanced when referring symptomatic patients.
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Affiliation(s)
- Christian von Wagner
- Department of Epidemiology and Public Health, University College London, University College Hospital, Level 2, Podium, 235 Euston Road, London NW1 2BU, England
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Taylor SA. Commentary on small bowel imaging in Crohn's disease. Frontline Gastroenterol 2012; 3:3-4. [PMID: 28839622 PMCID: PMC5517245 DOI: 10.1136/flgastro-2011-100012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/30/2011] [Indexed: 02/04/2023] Open
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Boone D, Halligan S, Taylor SA. Evidence review and status update on computed tomography colonography. Curr Gastroenterol Rep 2011; 13:486-494. [PMID: 21773705 DOI: 10.1007/s11894-011-0217-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Computed tomographic (CT) colonography is being implemented increasingly in the USA and Europe, and in many centers it has become the radiological technique of choice for imaging the whole colorectum. Although high diagnostic accuracy has been demonstrated in both screening and symptomatic populations, controversy persists regarding implementation, who should interpret the examination, and its cost effectiveness, particularly in the context of primary colorectal cancer screening. Published research in recent years has demonstrated efficacy in a wide range of patient groups, striking technical improvements, and high levels of patient acceptability. New developments continue in the fields of computer aided detection, digital cleansing, and integration into positron emission tomography. The purpose of this review is to bring the reader up-to-date with the latest developments in CT colonography, in particular, those of the last year.
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Affiliation(s)
- Darren Boone
- Centre for Medical Imaging, University College Hospital, 250 Euston Road, London NW1 2BU, UK
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Almond LM, Bowley DM, Karandikar SS, Roy-Choudhury SH. Role of CT colonography in symptomatic assessment, surveillance and screening. Int J Colorectal Dis 2011; 26:959-66. [PMID: 21424390 DOI: 10.1007/s00384-011-1178-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/03/2011] [Indexed: 02/07/2023]
Abstract
INTRODUCTION When 'whole colonic imaging' is indicated, clinicians must decide between optical colonoscopy, barium enema and CT colonography (CTC). CTC is a relatively new technique which has become increasingly accessible in the UK over the past 5 years. As radiologists have gained experience and scanning parameters have standardised, there have been substantial improvements in both the accuracy and safety of CTC. METHODS We review evidence from observational studies and randomised trials, and draw on expert opinion, to provide a comprehensive discussion of the current role of CTC in both symptomatic and asymptomatic individuals. CONCLUSIONS The emergence of CTC could soon entirely obviate the need for barium enema. CTC now has a complementary role alongside colonoscopy in symptomatic patients and a possible future role in colorectal cancer screening in the UK.
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Affiliation(s)
- L Maximilian Almond
- Department of Colorectal Surgery, Heart of England NHS Foundation Trust, Birmingham, Birmingham, UK.
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20
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Pagés Llinás M, Darnell Martín A, Ayuso Colella J. CT colonography: What radiologists need to know. RADIOLOGIA 2011. [DOI: 10.1016/j.rxeng.2011.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Pagés Llinás M, Darnell Martín A, Ayuso Colella JR. [CT colonography: what radiologists need to know]. RADIOLOGIA 2011; 53:315-25. [PMID: 21696795 DOI: 10.1016/j.rx.2011.01.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 12/11/2010] [Accepted: 01/20/2011] [Indexed: 02/06/2023]
Abstract
In 2008, CT colonography was approved by the American Cancer Society as a technique for screening for colorectal cancer. This approval should be considered an important step in the recognition of the technique, which although still relatively new is already changing some diagnostic algorithms. This update about CT colonography reports the quality parameters necessary for a CT colonographic study to be diagnostic and reviews the technical innovations and colonic preparation for the study. We provide a brief review of the signs and close with a discussion of the current indications for and controversies about the technique.
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Affiliation(s)
- M Pagés Llinás
- Centro de Diagnóstico por la Imagen, Hospital Clínic de Barcelona, Barcelona, España.
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Boone D, Halligan S, Frost R, Kay C, Laghi A, Lefere P, Neri E, Stoker J, Taylor S. CT colonography: Who attends training? A survey of participants at educational workshops. Clin Radiol 2011; 66:510-6. [DOI: 10.1016/j.crad.2010.12.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 11/22/2010] [Accepted: 12/06/2010] [Indexed: 12/29/2022]
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Patient acceptability of CT colonography compared with double contrast barium enema: results from a multicentre randomised controlled trial of symptomatic patients. Eur Radiol 2011; 21:2046-55. [PMID: 21626363 DOI: 10.1007/s00330-011-2154-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 03/31/2011] [Accepted: 04/29/2011] [Indexed: 02/06/2023]
Abstract
OBJECTIVES To determine patient acceptability of barium enema (BE) or CT colonography (CTC). METHODS After ethical approval, 921 consenting patients with symptoms suggestive of colorectal cancer who had been randomly assigned and completed either BE (N = 606) or CTC (N = 315) received a questionnaire to assess experience of the clinical episode including bowel preparation, procedure and complications. Satisfaction, worry and physical discomfort were assessed using an adapted version of a validated acceptability scale. Non-parametric methods assessed differences between the randomised tests and the effect of patient characteristics. RESULTS Patients undergoing BE were significantly less satisfied (median 61, interquartile range [IQR] 54-67 vs. median 64, IQR 56-69; p = 0.003) and experienced more physical discomfort (median 40, IQR 29-52 vs. median 35.5, IQR 25-47; p < 0.001) than those undergoing CTC. Post-test, BE patients were significantly more likely to experience 'abdominal pain/cramps' (68% vs. 57%; p = 0.007), 'soreness' (57% vs. 37%; p < 0.001), 'nausea/vomiting' (16% vs. 8%; p = 0.009), 'soiling' (31% vs. 23%; p = 0.034) and 'wind' (92% vs. 84%; p = 0.001) and in the case of 'wind' to also rate it as severe (27% vs. 15%; p < 0.001). CONCLUSION CTC is associated with significant improvements in patient experience. These data support the case for CTC to replace BE.
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Wylie PN, Burling D. CT colonography: what the gastroenterologist needs to know. Frontline Gastroenterol 2011; 2:96-104. [PMID: 28839590 PMCID: PMC5517201 DOI: 10.1136/fg.2009.000380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/09/2010] [Indexed: 02/04/2023] Open
Affiliation(s)
- Peter N Wylie
- Radiology Department, Royal Free Hospital, London, UK
| | - David Burling
- Intestinal Imaging Centre, St Mark's Hospital, Harrow, UK
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Nicholson BD, Hyland R, Rembacken BJ, Denyer M, Hull MA, Tolan DJM. Colonoscopy for colonic wall thickening at computed tomography: a worthwhile pursuit? Surg Endosc 2011; 25:2586-91. [PMID: 21359889 DOI: 10.1007/s00464-011-1591-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 01/18/2011] [Indexed: 01/16/2023]
Abstract
BACKGROUND In the absence of official guidance for the management of colonic wall thickening identified by computed tomography (CT), a common clinical dilemma surrounds the volume of colonoscopies subsequently performed. METHODS To identify whether colonic wall thickening identified at CT consistently warrants colonoscopy, consecutive colonoscopies performed at Leeds Teaching Hospitals Trust in 2008 and recorded as "possible colonic lesion on cross-sectional abdominal CT" in an endoscopic database were retrospectively analyzed. Clinical, radiologic, colonoscopic, and histologic data were obtained from medical records. RESULTS Of 4,702 colonoscopies, 94 (2%) had a full data set meeting the inclusion criteria. The primary diagnoses were normal condition (n = 11, 11.7%), adenocarcinoma (n = 25, 26.6%), adenoma (n = 23, 24.5%), diverticular disease (n = 12, 12.8%), nonspecific colitis (n = 6, 6.4%), Crohn's disease (n = 4, 4.3%), and hyperplastic polyp (n = 3, 3.2%). Computed tomography and colonoscopy were concordant for specific pathology in 79.8% of the cases (n = 75). Compared with diagnosis after histology, colonoscopy alone correctly identified specific pathology in 18.1% of the cases (n = 17), and CT alone was correct in 4.3% of the cases (n = 4)), whereas both were incorrect in 3.2% of the cases (n = 3). Computed tomography had a sensitivity of 72.3% (95% confidence interval [95% CI], 61.9-80.8%), a specificity of 96.5% (95% CI, 94.9-97.6%), a positive predictive value of 72.3%, and a negative predictive value of 96.5%. In 63.8% of the cases (n = 60), CT identified pathology necessitating further intervention at the time of colonoscopy or afterward, and in 28.7% of the cases (n = 27), CT identified pathology requiring no additional intervention. In the remaining 7.4% of the cases (n = 7), CT detected no new pathology. CONCLUSION Computed tomography is highly predictive of colonic pathology compared with final outcome after colonoscopy and biopsy. For patients without a pre-existing diagnosis, colonic wall thickening demonstrated at CT warrants further investigation with colonoscopy.
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Affiliation(s)
- Brian D Nicholson
- Department of Gastroenterology, Leeds Teaching Hospitals NHS Trust, Leeds General Infirmary, Great George St., Leeds, LS1 3EX, UK
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Samee A, Selvasekar CR. Current trends in staging rectal cancer. World J Gastroenterol 2011; 17:828-34. [PMID: 21412492 PMCID: PMC3051133 DOI: 10.3748/wjg.v17.i7.828] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 11/12/2010] [Accepted: 11/19/2010] [Indexed: 02/06/2023] Open
Abstract
Management of rectal cancer has evolved over the years. In this condition preoperative investigations assist in deciding the optimal treatment. The relation of the tumor edge to the circumferential margin (CRM) is an important factor in deciding the need for neoadjuvant treatment and determines the prognosis. Those with threatened or involved margins are offered long course chemoradiation to enable R0 surgical resection. Endoanal ultrasound (EUS) is useful for tumor (T) staging; hence EUS is a useful imaging modality for early rectal cancer. Magnetic resonance imaging (MRI) is useful for assessing the mesorectum and the mesorectal fascia which has useful prognostic significance and for early identification of local recurrence. Computerized tomography (CT) of the chest, abdomen and pelvis is used to rule out distant metastasis. Identification of the malignant nodes using EUS, CT and MRI is based on the size, morphology and internal characteristics but has drawbacks. Most of the common imaging techniques are suboptimal for imaging following chemoradiation as they struggle to differentiate fibrotic changes and tumor. In this situation, EUS and MRI may provide complementary information to decide further treatment. Functional imaging using positron emission tomography (PET) is useful, particularly PET/CT fusion scans to identify areas of the functionally hot spots. In the current state, imaging has enabled the multidisciplinary team of surgeons, oncologists, radiologists and pathologists to decide on the patient centered management of rectal cancer. In future, functional imaging may play an active role in identifying patients with lymph node metastasis and those with residual and recurrent disease following neoadjuvant chemoradiotherapy.
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Robinson C, Halligan S, Iinuma G, Topping W, Punwani S, Honeyfield L, Taylor SA. CT colonography: computer-assisted detection of colorectal cancer. Br J Radiol 2010; 84:435-40. [PMID: 21081583 DOI: 10.1259/bjr/17848340] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES Computer-aided detection (CAD) for CT colonography (CTC) has been developed to detect benign polyps in asymptomatic patients. We aimed to determine whether such a CAD system can also detect cancer in symptomatic patients. METHODS CTC data from 137 symptomatic patients subsequently proven to have colorectal cancer were analysed by a CAD system at 4 different sphericity settings: 0, 50, 75 and 100. CAD prompts were classified by an observer as either true-positive if overlapping a cancer or false-positive if elsewhere. Colonoscopic data were used to aid matching. RESULTS Of 137 cancers, CAD identified 124 (90.5%), 122 (89.1%), 119 (86.9%) and 102 (74.5%) at a sphericity of 0, 50, 75 and 100, respectively. A substantial proportion of cancers were detected on either the prone or supine acquisition alone. Of 125 patients with prone and supine acquisitions, 39.3%, 38.3%, 43.2% and 50.5% of cancers were detected on a single acquisition at a sphericity of 0, 50, 75 and 100, respectively. CAD detected three cancers missed by radiologists at the original clinical interpretation. False-positive prompts decreased with increasing sphericity value (median 65, 57, 45, 24 per patient at values of 0, 50, 75, 100, respectively) but many patients were poorly prepared. CONCLUSION CAD can detect symptomatic colorectal cancer but must be applied to both prone and supine acquisitions for best performance.
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Affiliation(s)
- C Robinson
- Centre for Medical Imaging, University College Hospital, London, UK
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Haycock A, Burling D, Wylie P, Muckian J, Ilangovan R, Thomas-Gibson S. CT colonography training for radiographers--a formal evaluation. Clin Radiol 2010; 65:997-1004. [PMID: 21070904 DOI: 10.1016/j.crad.2010.05.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 05/10/2010] [Accepted: 05/11/2010] [Indexed: 12/15/2022]
Abstract
AIMS To evaluate the efficacy of a new intensive "hands-on" course designed to train small teams of radiographers in computed tomography colonography (CTC) technique and initial interpretation for patient triage. MATERIALS AND METHODS The course comprised small-group lectures, active participation in the daily CTC service with practical technique and image interpretation training by experienced radiologists and radiographers. Evaluation was by assessment of knowledge using randomized sets of multiple choice questions (MCQ; pre/post-course), practical technique using checklists and expert global scores, and interpretation performance outcomes using randomized pre/post-course test datasets (five validated CTC examinations each). Paired t-tests were used to investigate change in performance for MCQ score and interpretation accuracy. RESULTS Thirteen courses with 49 participants were evaluated over 2 years. Practical skills were high, with mean (SD) checklist scores of 14/15 (0.85) and global scores of 26/30 (2.3). MCQ scores increased significantly from a mean of 59% pre-course to 69% post-course, p<0.001. Correct classification of CTC examination improved significantly from a mean of 55% pre-course to 71% post-course, p<0.001. Cancer and large polyp (>10mm) detection rates also improved significantly from 49% to 60%, p=0.002. CONCLUSION Structured training in CTC can significantly improve knowledge and interpretation skills of radiographers, while assessing safe procedural performance. Implementation of similar programmes nationally may help reduce performance gaps between centres.
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Affiliation(s)
- A Haycock
- Intestinal Imaging Centre and Wolfson Unit for Endoscopy, St Mark's Hospital, Imperial College London, London, UK
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Abstract
Computed tomography colonography (CTC) in colorectal cancer (CRC) screening has two roles: one present and the other potential. The present role is, without any further discussion, the integration into established screening programs as a replacement for barium enema in the case of incomplete colonoscopy. The potential role is the use of CTC as a first-line screening method together with Fecal Occult Blood Test, sigmoidoscopy and colonoscopy. However, despite the fact that CTC has been officially endorsed for CRC screening of average-risk individuals by different scientific societies including the American Cancer Society, the American College of Radiology, and the US Multisociety Task Force on Colorectal Cancer, other entities, such as the US Preventive Services Task Force, have considered the evidence insufficient to justify its use as a mass screening method. Medicare has also recently denied reimbursement for CTC as a screening test. Nevertheless, multiple advantages exist for using CTC as a CRC screening test: high accuracy, full evaluation of the colon in virtually all patients, non-invasiveness, safety, patient comfort, detection of extracolonic findings and cost-effectiveness. The main potential drawback of a CTC screening is the exposure to ionizing radiation. However, this is not a major issue, since low-dose protocols are now routinely implemented, delivering a dose comparable or slightly superior to the annual radiation exposure of any individual. Indirect evidence exists that such a radiation exposure does not induce additional cancers.
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Murphy R, Slater A, Uberoi R, Bungay H, Ferrett C. Reduction of perception error by double reporting of minimal preparation CT colon. Br J Radiol 2009; 83:331-5. [PMID: 19651707 DOI: 10.1259/bjr/65634575] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Minimal preparation CT colon (MPCTC) is a useful test for frail elderly patients, who tolerate full bowel preparation poorly, and has the potential advantage of identifying extra-colonic pathology. Double reporting has been shown to reduce perception errors in a variety of radiological investigations, and we sought to determine its usefulness for MPCTC. A prospective consecutive cohort of 186 patients undergoing MPCTC for lower gastrointestinal symptoms was double reported. Radiologists were blinded to each report. Data for each report were divided into colonic and extra-colonic findings, with the latter being graded as clinically relevant or irrelevant. Discrepancies between the two reports were identified. A positive colonic lesion was defined as one where direct endoscopic visualisation was recommended. A clinically relevant extra-colonic lesion was defined as one that could impact on future patient management. 13% (24/186) of patients had a significant colonic lesion; 7 of these were identified only by 1 observer, although only 1 was confirmed endoscopically to be cancer. The positive predictive value for colon cancer was 69% for single reporting and 54.5% for double reporting. There were 67 clinically relevant extra-colonic lesions, and 25 of these were reported only by only 1 observer. In conclusion, double reporting found one extra-colonic cancer, but at the expense of five unnecessary endoscopic procedures. This seems a reasonable trade-off and we would therefore recommend double reporting. However, implementation would have a significant impact on manpower and service delivery.
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Affiliation(s)
- R Murphy
- Department of Radiology, John Radcliffe Hospital, Headley Way, Headington, Oxford OX3 9DU, UK
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Thomas S, Atchley J, Higginson A. Audit of the introduction of CT colonography for detection of colorectal carcinoma in a non-academic environment and its implications for the national bowel cancer screening programme. Clin Radiol 2009; 64:142-7. [DOI: 10.1016/j.crad.2008.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 10/01/2008] [Accepted: 10/14/2008] [Indexed: 11/27/2022]
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Sidhu R, Sanders DS, Thomson M, McAlindon ME. Is this the end of an era for conventional diagnostic endoscopy? Clin Med (Lond) 2009; 9:39-41. [PMID: 19271599 PMCID: PMC5922630 DOI: 10.7861/clinmedicine.9-1-39] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- R Sidhu
- Gastroenterology and Liver Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospital NHS Trust, Sheffield.
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Nagata K, Näppi J, Cai W, Yoshida H. Minimum-invasive early diagnosis of colorectal cancer with CT colonography: techniques and clinical value. ACTA ACUST UNITED AC 2008; 2:1233-46. [DOI: 10.1517/17530059.2.11.1233] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Halligan S, Taylor SA. Is CT colonography superior to colonoscopy for the detection of advanced neoplasia? NATURE CLINICAL PRACTICE. GASTROENTEROLOGY & HEPATOLOGY 2008; 5:248-249. [PMID: 18382433 DOI: 10.1038/ncpgasthep1102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 01/07/2008] [Indexed: 05/26/2023]
Affiliation(s)
- Steve Halligan
- S Halligan is Professor of Gastrointestinal Radiology and SA Taylor is a Senior Lecturer in Diagnostic Radiology at University College Hospital, London, UK
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Sanner T. Formation of transient complexes in the glutamate dehydrogenase catalyzed reaction. Biochemistry 1975; 14:5094-5098. [PMID: 39 DOI: 10.1021/bi00694a011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The reaction of glutamate dehydrogenase and glutamate (gl) with NAD+ and NADP+ has been studied with stopped-flow techniques. The enzyme was in all experiments present in excess of the coenzyme. The results indicate that the ternary complex (E-NAD(P)H-kg) is present as an intermediate in the formation of the stable complex (E-NAD(P)H-gl). The identification of the complexes is based on their absorption spectra. The binding of the coenzyme to (E-gl) is the rate-limiting step in the formation of (E-NAD(P)H-kg) while the dissociation of alpha-ketoglutarate (kg) from this complex is the rate-limiting step in the formation of (E-NAD(P)H-gl). The Km for glutamate was 20-25 mM in the first reaction and 3 mM in the formation of the stable complex. The Km values were independent of the coenzyme. The reaction rates with NAD+ were approximately 50% greater than those with NADP+. Furthermore, high glutamate concentration inhibited the formation of (E-NADH-kg) while no substrate inhibition was found with NADP+ as coenzyme. ADP enhanced while GTP reduced the rate of (E-NAD(P)H-gl) formation. The rate of formation of (E-NAD(P)H-kg) was inhibited by ADP, while it increased at high glutamate concentration when small amounts of GTP were added. The results show that the higher activity found with NAD+ compared to NADP+ under steady-state assay conditions do not necessarily involve binding of NAD+ to the ADP activating site of the enzyme. Moreover, the substrate inhibition found at high glutamate concentration under steady-state assay condition is not due to the formation of (E-NAD(P)H-gl) as this complex is formed with Km of 3 mM glutamate, and the substrate inhibition is only significant at 20-30 times this concentration.
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