Colorectal cancer screening is thought to be an effective tool with which to reduce the mortality from colorectal cancer through early detection and removal of colonic adenomas and early colon cancers. In this article, we review the history, evolution, and current status of imaging tests of the colon-including single-contrast barium enema, double-contrast barium enema, computed tomographic (CT) colonography, and magnetic resonance (MR) colonography-for colorectal cancer screening. Despite its documented value in the detection of colonic polyps, the double-contrast barium enema has largely disappeared as a screening test because it is widely perceived as a labor-intensive, time-consuming, and technically demanding procedure. In the past decade, the barium enema has been supplanted by CT colonography as the major imaging test in colorectal cancer screening in the United States, with MR colonography emerging as another viable option in Europe. Although MR colonography does not require ionizing radiation, the radiation dose for CT colonography has decreased substantially, and regular screening with this technique has a high benefit-to-risk ratio. In recent years, CT colonography has been validated as an effective tool for use in colorectal cancer screening that is increasingly being disseminated.

To Evaluate the indications versus diagnostic yield of significant colonic neoplasia (SCN) in the open-access era and screening colonoscopy.

During 6-year period, all procedural data were obtained from all consecutive patients who underwent colonoscopies. Indications were compared with American Society for Gastrointestinal Endoscopy guidelines.

In all 22,341 procedures were included in the study. Indications were divided into 3 groups: Screening (21.89% of the procedures), surveillance (17.60%) and symptoms/signs (60.51%). A total of 2867 patients (12.83%) had SCNs. Of these, 278 (7.00%) SCNs were found in the group less than 50 years of age and 2589 in the group over the age of 50 years (14.10%). SCN as per indication frequency was 12.69% in the symptom/sign group (subdivided to 7.24% and 14.01% in the under 50 and over 50, age groups, respectively); screening 13.37% (5.48% and 15.09%, respectively); surveillance 12.64% (8.48% and 13.19%, respectively). The indications leading to the highest SCN rate (over 25%) were: abnormal imaging, elevated carcinoembryonic antigen, and rectal pain.

Colonoscopy is a unique screening tool that can detect neoplastic lesions. SCN prevalence in our study was between 13% and 15% for all indications in patients above 50 years of age. This emphasizes performing a screening colonoscopy for the entire population over the age of 50 years, regardless of the indication. We feel that American Society for Gastrointestinal Endoscopy guidelines should be reassessed. The revised criteria should state that the primary indication, are all people over the age of 50 years, who should have a colonoscopy performed, unless otherwise contraindicated.

Appropriateness in GI endoscopy is critical to face the rising amount of demands. Education of physicians has been advocated to reduce the level of inappropriateness.

Our purpose was to assess the effectiveness of an educational program in determining a reduction of inappropriate colonoscopies in an open access system.

Prospective study.

A single endoscopy unit in Italy.

A total of 495 consecutive outpatients referred to our endoscopy unit by family physicians for diagnostic colonoscopy before the educational course and 522 after its completion, for a total of 1017 patients.

Inappropriate colonoscopy reduction rates, cost savings, and reduction of waiting lists were evaluated.

With regard to inappropriate colonoscopies, the post-course group rate of inappropriateness was significantly lower than that of the pre-course group (P < or = .001). The economic savings for 1 year was estimated to be euro19,000. The reduction of the waiting list was about 15% of the original value.

Education has a high incidence in reducing inappropriate colonoscopies in an open-access system determining reduction of costs and waiting lists.

To evaluate if the guidelines for the appropriateness of performing colonoscopy by American Society for Gastrointestinal Endoscopy (AGSE) and Italian Society of Digestive Endoscopy (SIED) yield a good diagnostic efficacy and do not present risks of missing important colonic pathologies in an Italian population sample.

A total of 1017 consecutive patients (560 men and 457 women; mean age 64.4 +/- 16 years) referred to an open-access endoscopy unit for colonoscopy from July 2004 to May 2006 were evaluated according to ASGE and SIED guidelines for appropriateness of performing the procedure. Diagnostic yield was defined as the percentage of relevant colonic pathologies of the total number of colonoscopies performed.

About 85.2% patients underwent colonoscopy that was considered appropriate based on at least one ASGE or SIED criterion, while it was considered inappropriate for 14.8% of patients. The diagnostic yield of colonoscopy was significantly higher for appropriate colonoscopies (26.94% vs 10.6%, P < 0.001) than for inappropriate colonoscopies (5.3%). There was no missed colorectal cancer following the ASGE/SIED criteria.

ASGE/SIED guidelines have shown a good diagnostic yield and the rate of missing relevant colonic pathologies seems very low. Unfortunately, the percentage of inappropriate referrals for colonoscopy in an open-access endoscopy system is still high, despite the number of papers published on the issue and the definition of international guidelines. Further steps are required to update and standardize the guidelines to increase their diffusion and to promote educational programs for general practitioners.

To assess the appropriateness of referrals and to determine the diagnostic yield of colonoscopy according to the 2000 guidelines of the American Society for Gastrointestinal Endoscopy (ASGE).

A total of 736 consecutive patients (415 males, 321 females; mean age 43.6+/-16.6 years) undergoing colonoscopy during October 2001-March 2002 were prospectively enrolled in the study. The 2000 ASGE guidelines were used to assess the appropriateness of the indications for the procedure. Diagnostic yield was defined as the ratio between significant findings detected on colonoscopy and the total number of procedures performed for that indication.

The large majority (64%) of patients had colonoscopy for an indication that was considered "generally indicated", it was "generally not indicated" for 20%, and it was "not listed" for 16% in the guidelines. The diagnostic yield of colonoscopy was highest for the "generally indicated" (38%) followed by "not listed" (13%) and "generally not indicated" (5%) categories. In the multivariable analysis, the diagnostic yield was independently associated with the appropriateness of indication that was "generally indicated" (odds ratio=12.3) and referrals by gastroenterologist (odds ratio =1.9).

There is a high likelihood of inappropriate referrals for colonoscopy in an open-access endoscopy system. The diagnostic yield of the procedure is dependent on the appropriateness of indication and referring physician's specialty. Certain indications "not listed" in the guidelines have an intermediate diagnostic yield and further studies are required to evaluate whether they should be included in future revisions of the ASGE guidelines.

The demand for gastrointestinal endoscopy is increasing in most developed countries, resulting in an important rise in overall costs and waiting lists for endoscopic procedures. Therefore, adherence to appropriate indications for these procedures is essential for the rational use of finite resources in an open-access system.

To assess indications and appropriateness of colonoscopy according to the European Panel on the Appropriateness of Gastrointestinal Endoscopy (EPAGE) criteria.

From May to June 2004, all consecutive patients referred to our Unit for open-access colonoscopy were considered for inclusion in this prospective study. Appropriateness of each colonoscopy was established according to the EPAGE criteria. In order to evaluate whether appropriateness of use correlated with the diagnostic yield of colonoscopy, relevant endoscopic findings were also recorded.

A total of 350 consecutive patients were included in the study. In 38 of them, the colonoscopy indication was not listed in the EPAGE guidelines and, consequently, they were not evaluated. In the remaining 312 patients, the indication for the procedure was considered inappropriate in 73 (23%) patients. Both referring doctor characteristics (specialty and health care setting) and patient data (age) correlated with appropriateness of endoscopy. The diagnostic yield was significantly higher for appropriate colonoscopies (42%) than in those judged inappropriate (21%) (P = 0.001).

A noteworthy proportion of patients referred for colonoscopy to an open-access endoscopy unit are considered inappropriate because of their indication, with significant differences among specialties. These results suggest that implementation of validated guidelines for its appropriate use could improve this situation and, considering the correlation between appropriateness and diagnostic yield, even contribute to improve the prognosis of patients with colorectal diseases.

The following issues and requirements related to the implementation of a CT colonography (CTC) service are important: (i) policies are needed regarding the indications for CTC. Concomitant with this is the need for education of potential referrers and patients. Expectations of the procedure, particularly by general practitioners, may be unrealistic and indications for referral may otherwise be inappropriate. At present there is not general acceptance of CTC for screening asymptomatic persons; (ii) a flexible approach to CT protocols is useful, dependent on the indication for and clinical context of referral, the age and body habitus of the patient; (iii) attention to the issues related to the special skills required by the reporting radiologist. While there is a temptation to regard CTC interpretation as an extension of skills used in interpreting other cross-sectional images, there is a need to realise that there are skills required specific to CTC and there should be adequate provision for training; (iv) matters related to reporting, such as reporting format, and lesions that will be reported/not reported; and (v) informed consent from the patient. Information should be provided with regard to the limitations of CTC, the implications of a positive finding and radiation dosage.

Health care costs are an increasingly important study outcome. Endoscopic practice consumes a large proportion of gastroenterology-related health expenses. An economic comparison of several currently accepted endoscopic practices was performed, ranking them according their cost-effectiveness, as viewed from the payer perspective. The cost-effectiveness of four currently accepted standard endoscopic practices was examined: small bowel biopsy to assess for celiac sprue, colonoscopic biopsy to assess for microscopic colitis, surveillance of Barrett's esophagus, and surveillance of chronic ulcerative colitis (CUC). Parameter estimates were obtained from the published literature. Charges were based on Medicare professional plus facility/technical fees. Performing colonoscopic biopsies for microscopic colitis in the setting of chronic nonbloody diarrhea was the most cost-effective practice ($2447/case detected), while small bowel biopsy for sprue in the setting of a patient with a first-degree relative with sprue ($3042/case detected) or with anemia ($2982/case detected) was also a cost-effective approach. Small bowel biopsy in the setting of diarrhea ($3900/case detected) was less cost-effective, while CUC surveillance ($14,119/detection of dysplasia) and performance of small bowel biopsy in an asymptomatic patient ($15,209/case detected) were clearly the least economical. As efforts are made to reduce the costs of health care, more attention will be focused on the cost-effectiveness of routine endoscopic practices. Although, our findings put endoscopic practices into economic perspective, future perspective, future prospective trials are required to confirm the validity of these findings.

Colonoscopy is the best way of imaging the colon with concurrent biopsy and treatment. However it is expensive, requires full bowel preparation, and carries a risk of complications. Flexible sigmoidoscopy is an alternative way to investigate symptoms that raise the suspicion of a lesion of the rectum or left colon.

To evaluate flexible sigmoidoscopy as the main investigation for "left sided" colorectal symptoms.

The clinical records of 317 patients who were assessed at a colorectal specialist clinic and were thought to have a suspicion of a lesion of the rectum or left colon were retrospectively reviewed. All patients had flexible sigmoidoscopy as the primary investigation. Primary outcome was the diagnostic yield of flexible sigmoidoscopy and secondary outcomes were any additional colonic investigations required, failure rates, and complication rates.

Three hundred and sixteen patients who had flexible sigmoidoscopy with the above criteria were retrospectively analysed. Twenty four procedures (7.6%) had to be abandoned because of poor bowel preparation. The examination was considered complete when it reached the splenic flexure, which was the case in 205 cases (65%). In 137 flexible sigmoidoscopies (43.3%) there were no abnormal findings. Of the remaining 179 a carcinoma of the rectum or colon was found in 28 cases (8.8%) and one or more polyps was found in 57 (18%) cases. On the basis of the findings it was calculated that 31% of the patients would require an additional investigation for further imaging of the right colon.

Although flexible sigmoidoscopy has a high yield of pathologies when carried out by a specialist colorectal clinic, the presence of those pathologies makes the full imaging of the whole colon with an additional investigation necessary. Therefore the cost efficiency of flexible sigmoidoscopy is questionable. Although flexible sigmoidoscopy is indicated for certain patients, it cannot replace colonoscopy as the main investigation used by a specialist colorectal clinic.

This article describes diagnostic radiologists' colorectal cancer screening activities and beliefs about screening effectiveness and future capacity for screening with double-contrast barium enema, and compares radiologists' opinions about colorectal cancer screening with those of primary care physicians.

We surveyed a nationally representative sample of diagnostic radiologists. Of 381 eligible radiologists, 312 (82%) responded. Descriptive statistics and chi-square tests were used to assess radiologists' opinions about double-contrast barium enema volume and capacity and to compare radiologists' beliefs about colorectal cancer screening with those of primary care physicians. Logistic regression was used to identify characteristics of radiologists who receive referrals for or perform a higher volume of screening double-contrast barium enema and of those who expect the volume of double-contrast barium enemas to increase.

Seventy-five percent of radiologists said that double-contrast barium enema is a "very effective" colorectal cancer screening procedure compared with 33% of primary care physicians. Although 86% of radiologists reported performing one or more screening double-contrast barium enema procedures during a typical month, only 27% indicated that they did so 11 or more times. Fifteen percent of radiologists said that their double-contrast barium enema volume had increased over the past 3 years, and 50% expect an increase over the next 3 years. Only 8% said that the capacity of facilities and personnel to meet the demand for double-contrast barium enemas in their geographic area of practice is inadequate. Geographic region and belief in double-contrast barium enema efficacy were predictors of double-contrast barium enema volume and referrals.

Most diagnostic radiologists perform colorectal cancer screening with double-contrast barium enema, but procedure volumes are modest. Because primary care physicians view double-contrast barium enema less positively than do radiologists, radiologists' expectations for an increased volume of double-contrast barium enemas over the next few years may not be realized.

Computed tomography examination of the colon performed after bowel cleansing and distension of the lumen with gas goes by several different names--CT colonography (CTC) and CT colography perhaps being the most common. Strictly, the term 'virtual colonoscopy' (VC), should be reserved for the process of examining 3-D, simulated endoluminal images with a capability to navigate through the bowel using appropriate software. Computed tomography colonography appears to be the name that has gained favour among radiologists, although it is suspected that 'virtual colonoscopy' will persist as a generic term due to its attractive 'high-tech' connotations for non-radiological medical and lay persons. Whatever the name, the technique has been made possible through the advent of fast helical CT scanners which allow acquisition of a volume of data, and of proprietary software which enables multiplanar reformatting and 3-D endoluminal reconstructions. It is evident that if CTC/VC can be shown to be acceptable to patients, safe, affordable and accurate, it has enormous potential as a diagnostic and screening tool for colorectal neoplasia.

Variables influencing radiation exposure were studied using analysis of covariance in 523 double contrast barium enemas performed by 21 radiology residents (12 female, 9 male). Dose-area products (DAPs) (ns), number of exposures per patient (p < 0.05) and screening times (p < 0.05) were higher for female residents (mean 52.0 Gy cm2, 9.55 exposures and 4.02 min, respectively) than for male residents (mean 41.7 Gy cm2, 8.26 exposures and 3.20 min, respectively). The number of lectures on radiation protection attended by the resident (range 0-20) had no significant effect on these radiation-related variables. Other factors explaining these variables were patient age, diagnosis and anteroposterior thickness. Radiologists' use of ionizing radiation during fluoroscopy may be sex-related. Traditional lecture-based education on radiation protection was not effective with this group; thus, improved methods should be developed to control doses.

Efforts to decrease overuse of health care may result in underuse. Overuse and underuse of colonoscopy have never been simultaneously evaluated in the same patient population.

In this prospective observational study, the appropriateness and necessity of referral for colonoscopy were evaluated by using explicit criteria developed by a standardized expert panel method. Inappropriate referrals constituted overuse. Patients with necessary colonoscopy indications who were not referred constituted underuse. Consecutive ambulatory patients with lower gastrointestinal (GI) symptoms from 22 general practices in Switzerland, a country with ready access to colonoscopy, were enrolled during a 4-week period. Follow-up data were obtained at 3 months for patients who did not undergo a necessary colonoscopy.

Eight thousand seven hundred sixty patient visits were screened for inclusion; 651 patients (7.4%) had lower GI symptoms (mean age 56.4 years, 68% women). Of these, 78 (12%) were referred for colonoscopy. Indications for colonoscopy in 11 patients (14% of colonoscopy referrals or 1.7% of all patients with lower GI symptoms) were judged inappropriate. Among 573 patients not referred for the procedure, underuse ranged between 11% and 28% of all patients with lower GI symptoms, depending on the criteria used.

Applying criteria from an expert panel of nationally recognized experts indicates that underuse of referral for colonoscopy exceeds overuse in primary care in Switzerland. To improve quality of care, both overuse and underuse of important procedures must be addressed.

To assess magnetic resonance (MR) colonography as a method for detection of colorectal masses, with conventional colonoscopy as the reference standard.

MR colonography was performed in 132 patients referred for colonoscopy because of the possible presence of a mass. After rectal filling with a gadopentetate dimeglumine and water enema, T1-weighted three-dimensional gradient-echo MR studies were acquired with the patient in the prone and supine positions. Water-sensitive single-shot fast spin-echo MR images were also obtained. Surface-rendered virtual endoscopic endoluminal views, orthogonal sections in three planes, and water-sensitive MR images were interactively assessed for presence of colorectal masses by two radiologists.

MR colonography was well tolerated without sedation or analgesia. MR image quality was sufficient for diagnosis in 127 (96%) patients. Most small (</=5-mm-diameter) masses were overlooked at MR colonography, but 19 of 31 6-10-mm lesions and 26 of 27 large (>10-mm) lesions were correctly identified. For these large masses, MR colonography had a sensitivity of 93%, specificity of 99%, positive predictive value of 92%, and negative predictive value of 98% for detection of masses.

MR colonography is a promising modality for help in detecting colorectal mass lesions larger than 10 mm in diameter.

This study was done to determine whether sigmoidoscopy could theoretically constitute sufficient investigation for some patients with bright red rectal bleeding.

One hundred and forty-three patients undergoing investigative colonoscopy for bright red rectal bleeding and whose source of bleeding was identified were studied. The investigation took place in a large urban hospital over an 11-month period. Data obtained included changes in stool pattern, characteristics of the bleeding, lesions identified, and the distance of the lesion from the anus.

In patients younger than 55 yr, all serious lesions except for one malignancy in a patient with massive bleeding lay within 60 cm of the anus and theoretically within reach of the fiberoptic sigmoidoscope. The mixing of red blood with stool was commonly due to distal lesions, especially hemorrhoids.

In young persons with bright red rectal bleeding, fiberoptic sigmoidoscopy may prove to constitute appropriate initial investigation.

To identify criteria which may predict yield of neoplasia at colonoscopy.

Clinicopathological characteristics of patients undergoing colonoscopy for either surveillance for neoplasia or investigation of colorectal symptoms were reviewed. Logistic regression was used to analyse risks for detection of adenoma and carcinoma.

A total of 493 consecutive colonoscopies was reviewed. In the surveillance group, risk for detection of adenoma was two-fold greater in the elderly (>65 years), in male patients and in those with a previous history of adenoma as opposed to carcinoma. In symptomatic patients, risk for detection of any neoplasm was three-fold greater in the elderly but was independent of gender and presence or absence of rectal bleeding.

These data support a case for prioritization of elderly patients for colonoscopy. The value of surveillance colonoscopy in preventing colorectal cancer appears greater in patients with a previous history of adenoma as opposed to carcinoma. Strict selection of patients with non-bleeding symptoms may result in a colonoscopic yield of neoplasia comparable to that in patients with rectal bleeding.

The recent interest in guidelines for colorectal cancer diagnosis, management and in screening has important implications for radiologists. The present article reviews the role of the barium enema in colorectal neoplasia diagnosis in symptomatic patients, and in the context of screening programmes.

Prospective data describing the appropriateness of use of colonoscopy based on detailed panel-based clinical criteria are not available.

In a cohort of 553 consecutive patients referred for colonoscopy to two university-based Swiss outpatient clinics, the percentage of patients who underwent colonoscopy for appropriate, equivocal, and inappropriate indications and the relationship between appropriateness of use and the presence of relevant endoscopic lesions was prospectively assessed. This assessment was based on criteria of the American Society for Gastrointestinal Endoscopy and explicit American and Swiss criteria developed in 1994 by a formal panel process using the RAND/UCLA appropriateness method.

The procedures were rated appropriate or equivocal in 72.2% by criteria of the American Society for Gastrointestinal Endoscopy, in 68.5% by explicit American criteria, and in 74.4% by explicit Swiss criteria (not statistically significant, NS). Inappropriate use (overuse) of colonoscopy was found in 27.8%, 31.5%, and 25.6%, respectively (NS). The proportion of appropriate procedures was higher with increasing age. Almost all reasons for using colonoscopy could be assessed by the two explicit criteria sets, whereas 28.4% of reasons for using colonoscopy could not be evaluated by the criteria of the American Society for Gastrointestinal Endoscopy (p < 0.0001). The probability of finding a relevant endoscopic lesion was distinctly higher in the procedures rated appropriate or equivocal than in procedures judged inappropriate.

The rate of inappropriate use of colonoscopy is substantial in Switzerland. Explicit criteria allow assessment of almost all indications encountered in clinical practice. In this study, all sets of appropriateness criteria significantly enhanced the probability of finding a relevant endoscopic lesion during colonoscopy.

Oral regimens for bowel preparation before barium enema examination are routinely used because of their convenience and simplicity, rather than the traditional method of colonic wash-out. We performed a prospective study comparing the side-effects and efficacy of two commonly used oral bowel evacuants (Citromag and Golytely) for bowel preparation before barium enema examination in 102 patients. The side-effects associated with the agents were assessed by analysing a questionnaire completed by the patients. There was no significant difference in the side-effects between the two agents although more patients taking Golytely (45.5%) deemed its taste unacceptable than those taking Citromag (25.9%). The results of the bowel preparation were assessed by two independent radiologists giving scores on the amount of faecal residue and the quality of mucosal coating. The amount of faecal residue was less in the Golytely group (p < 0.05). The quality of mucosal coating by barium was also better in the Golytely group than the Citromag group (p < 0.05).

An evaluator-blinded randomized clinical trial was undertaken to assess the effectiveness and patient acceptance of three bowel cleansing regimens: conventional cleansing enema, Pico-salax and Golytely.

One hundred and fifty patients, referred for barium enema examination, were allocated to one of the three regimens. Both the radiographers and the radiologists did not know the method of preparation. Radiographers were requested to enter the patients' data, the number of bowel openings, the patients' comments of the preparation and side effects. Films were reviewed independently by two experienced radiologists for the degree of bowel cleanliness and quality of barium coating.

The mean (standard deviation) of bowel opening frequency for the cleansing enema, Pico-Salax and Golytely were 3.6(4.4), 8.3(4.8) and 7.1(4.2), respectively, with less bowel opening in the cleansing enema. There was less nausea associated with the cleansing enema (P = 0.006), more vomiting with Golytely (P = 0.008), less abdominal fullness with Pico-salax (P = 0.0006), less anorectal irritation with Golytely (P = 0.025), and no difference in the abdominal pain amongst three groups. There was no statistically significant difference in the number of bowel openings between the groups. Patients found that Pico-salax tasted better than Golytely (P = 0.0094) and Golytely was less accepted in the amount of fluid intake (P = 0.0018 and P < 0.0002 comparing Golytely with the cleansing enema and Pico-salax). Chi-squared testing showed no statistically significant difference in bowel cleanliness and quality of barium coating among the three preparations.

There was no difference in the effectiveness of the three regimens. Pico-salax seems the most acceptable because it has the fewest side effects.