For nodal regrowth in patients with rectal cancer following watch-and-wait, standardized protocols on diagnostic procedures and subsequent treatment are lacking.

To evaluate the diagnosis and treatment of suspected nodal regrowth following an organ preservation approach.

Patients were included from national and institutional watch-and-wait databases.

Thirty-five rectal cancer patients with suspected nodal regrowth on MRI were retrospectively identified during watch-and-wait follow-up.

Twenty-seven of 35 patients followed the watch-and-wait schedule after neoadjuvant (chemo)radiotherapy and 8 of 35 patients followed the watch-and-wait schedule after local excision for early rectal cancer.

Diagnostic procedures, treatment, and histopathological outcome.

The median follow-up was 34 months. The median time from the end of (chemo)radiotherapy or local excision to the first detection of suspected nodal regrowth on MRI following watch-and-wait was 9 and 10 months. After the first detection, 17 of 35 patients underwent immediate treatment without further diagnostics, of whom 7 also had luminal regrowth. In 18 of 35 patients, additional diagnostic procedures were performed. In 4 of 18 patients, PET-CT or endorectal ultrasound-guided biopsy was performed, and treatment was initiated on the basis of increased nodal regrowth suspicion. In 14 of 18 patients, MRI was repeated after 8 to 12 weeks: growth of suspected lymph nodes was the most decisive factor to proceed to treatment. In 8 patients, repeated MRI was combined with PET-CT and/or endorectal ultrasound-guided biopsy: in half of them, it contributed to treatment initiation. In total, 34 of 35 patients were treated: 9 received (re-)irradiation and 33 underwent total mesorectal excision. In 27 of 33 patients, nodal regrowth was pathologically confirmed in the total mesorectal excision-resection specimen; 5 of 6 patients without nodal involvement had pathologically confirmed luminal regrowth.

Highly selected study population.

During watch-and-wait follow-up of patients with rectal cancer in an organ preservation strategy, MRI plays an important role in the diagnosis of nodal regrowth. Repeated MRI after an interval can be helpful in making treatment decisions, and the role of PET-CT and endorectal ultrasound-guided biopsy appears limited. See Video Abstract .

ANTECEDENTES:Para el recrecimiento ganglionar en pacientes con cáncer de recto posterior a watch-and-wait (W&W), faltan protocolos estandarizados de sobre procedimientos de diagnóstico y tratamiento subsecuente.OBJETIVO:Evaluar el diagnóstico y tratamiento de sospecha de recrecimiento ganglionar posterior a tratamiento de preservación del órgano.ENTORNO CLINICO:Se incluyeron pacientes de la base de datos W&W nacionales e institucionales.DISEÑO:Se identificaron retrospectivamente 35 pacientes con cáncer de recto con sospecha de recrecimiento ganglionar en la resonancia magnética durante el seguimiento de W&W.PACIENTES:27 de 35 pacientes siguieron el programa W&W después de (quimio)radioterapia neoadyuvante y 8 de 35 siguieron el programa W&W después de la escisión local en cáncer rectal temprano.PRINCIPALES MEDIDAS DE RESULTADO:Procedimientos de diagnóstico, tratamiento y resultado histopatológico.RESULTADOS:La mediana de seguimiento fue de 34 meses. La mediana de tiempo desde el final de la (quimio)radioterapia o la escisión local hasta la primera detección de un presunto recrecimiento ganglionar en la resonancia magnética después de W&W fue de 9 y 10 meses. Después de la primera detección, 17 de 35 pacientes fueron sometidos a tratamiento inmediato sin diagnóstico adicional, de los cuales 7 también tuvieron un nuevo crecimiento luminal. En 18 de 35 pacientes se realizaron procedimientos de diagnóstico adicionales. En 4 de 18 pacientes se realizó PET-CT o biopsia guiada por ecografía endorrectal (ERUS) y se inició tratamiento en base a una mayor sospecha de recrecimiento ganglionar. En 14 de 18 pacientes, la resonancia magnética se repitió después de 8 a 12 semanas: el crecimiento de los ganglios linfáticos sospechosos fue el factor más decisivo para proceder al tratamiento. En 8 pacientes, la resonancia magnética repetida se combinó con PET-CT y/o biopsia guiada por ERUS: en la mitad de ellos contribuyó al inicio del tratamiento. En total, se trataron 34 de 35 pacientes: 9 recibieron (re)irradiación y 33 se sometieron a escisión total de mesorrecto. En 27 de 33 pacientes se confirmó patológicamente el recrecimiento ganglionar en la muestra de escisión total de mesorrecto; 5 de 6 pacientes sin afectación ganglionar tuvieron un recrecimiento luminal patológicamente confirmado.LIMITACIONES:Población de estudio altamente seleccionada.CONCLUSIONES:Durante el seguimiento de W&W de pacientes con cáncer de recto en estrategia de preservación de órganos, la resonancia magnética juega un papel importante en el diagnóstico del recrecimiento ganglionar. La repetición de la resonancia magnética después de un intervalo puede ser útil para tomar decisiones de tratamiento, y el papel de la PET-CT y la biopsia guiada por ERUS parece limitado. (Traducción- Dr. Francisco M. Abarca-Rendon ).

Background MRI plays a crucial role in restaging locally advanced rectal cancer treated with total neoadjuvant therapy (TNT); however, prospective studies have not evaluated its ability to accurately select patients for nonoperative management. Purpose To evaluate the ability of restaging MRI to predict oncologic outcomes and identify imaging features associated with residual disease (RD) after TNT. Materials and Methods This was a secondary analysis of the Organ Preservation in Rectal Adenocarcinoma (OPRA) trial, which randomized participants from April 2014 to March 2020 with stages II or III rectal adenocarcinoma to undergo either induction or consolidation TNT. Participants enrolled in the OPRA trial who underwent restaging MRI were eligible for inclusion in the present study. Radiologists classified participants as having clinical complete response (cCR), near-complete clinical response (nCR), or incomplete clinical response (iCR) based on restaging MRI at a mean of 8 weeks ± 4 (SD) after treatment. Oncologic outcomes according to MRI response category were assessed using Kaplan-Meier curves. Logistic regression analysis was performed to identify imaging characteristics associated with RD. Results A total of 277 participants (median age, 58 years [IQR, 17 years]; 179 male) who were randomized in the OPRA trial had restaging MRI forms completed. The median follow-up duration was 4.1 years. Participants with cCR had higher rates of organ preservation compared with those with nCR (65.3% vs 41.6%, log-rank P < .001). Five-year disease-free survival for participants with cCR, nCR, and iCR was 81.8%, 67.6%, and 49.6%, respectively (log-rank P < .001). The MRI response category also predicted overall survival (log-rank P < .001), distant recurrence-free survival (log-rank P = .005), and local regrowth (log-rank P = .02). Among the 266 participants with at least 2 years of follow-up, 129 (48.5%) had RD. At multivariable analysis, the presence of restricted diffusion (odds ratio, 2.50; 95% CI: 1.22, 5.24) and abnormal nodal morphologic features (odds ratio, 5.04; 95% CI: 1.43, 23.9) remained independently associated with RD. Conclusion The MRI response category was predictive of organ preservation and survival. Restricted diffusion and abnormal nodal morphologic features on restaging MRI scans were associated with increased likelihood of residual tumor. ClinicalTrials.gov identifier: NCT02008656 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Milot in this issue.

Locally advanced rectal cancer often requires neoadjuvant treatment (NAT) before surgical intervention. This study aimed to assess the concordance between preoperative magnetic resonance imaging (MRI) findings and postoperative pathology results after NAT in rectal cancer patients.

A retrospective analysis of 52 patients who underwent NAT and subsequent surgery at Ankara Bilkent City Hospital between May 2019 and May 2023 was conducted. Demographics, preoperative MRIs, time intervals between NAT, MRI, and surgery, and postoperative pathology were assessed.

The median age of the cohort was 59 years, with a male predominance (76.9%). Tumour T stage (κ = 0.157), lymph node stage (κ = 0.138), and circumferential resection margin (κ = 0.138) concordance showed poor agreement between post-neoadjuvant treatment (PNT) MRI and pathology. PNT MRI demonstrated a limited correlation with postoperative pathology.

While preoperative MRI is commonly used for restaging after NAT in rectal cancer, our study highlights its limited concordance with postoperative pathology. The sensitivity and specificity metrics, although reported in the literature, should be interpreted alongside concordance assessments for a comprehensive evaluation.

Rectal cancer has a high risk of recurrence and metastasis, with median survival ranging from 24 months to 36 months. K-RAS mutation is a predictor of poor prognosis in rectal cancer. Advanced rectal cancer can be stopped in its tracks by pelvic exenteration.

A 51-year-old woman was diagnosed with advanced rectal cancer (pT4bN2aM1b, stage IV) with the KRAS G12D mutation due to a change in bowel habits. The patient had experienced repeated recurrences of rectal cancer after initial radical resection, and the tumor had invaded the ovaries, sacrum, bladder, vagina and anus. Since the onset of the disease, the patient had undergone a total of seven surgeries and long-term FOLFIRI- or XELOX-based chemotherapy regimens, with the targeted agents bevacizumab and regorafenib. Fortunately, the patient was able to achieve intraoperative R0 resection in almost all surgical procedures and achieve tumor-free survival after pelvic exenteration. The patient has been alive for 86 months since her diagnosis.

Patients with advanced rectal cancer can achieve long-term survival through active multidisciplinary management and R0 surgery.

Preoperative determination of lymph node (LN) status is crucial in treatment planning for rectal cancer. This study prospectively evaluated the risk factors for lymph node metastasis (LNM) at staging and restaging based on a node-by-node pairing between MRI imaging findings and histopathology and constructed nomograms to evaluate its diagnostic value.

From July 2021 to July 2022, patients with histopathologically verified rectal cancer who underwent MRI before surgery were prospectively enrolled. Histological examination of each LN status in the surgical specimens and anatomical matching with preoperative imaging. Taking histopathological results as the gold standard, federating clinical features from patients and LN imaging features on MRI-T2WI. Risk factors for LN metastasis were identified by multivariate logistic regression analysis and used to create a nomogram. The performance of the nomograms was assessed with calibration plots and bootstrapped-concordance index and validated using validation cohorts.

A total of 500 target LNs in 120 patients were successfully matched with node-by-node comparisons. A total of 353 LNs did not receive neoadjuvant therapy and 147 LNs received neoadjuvant chemoradiotherapy (neoCRT). Characterization of LNs not receiving neoadjuvant therapy and multivariate regression showed that the short diameter, preoperative CEA level, mrT-stage, border contour, and signal intensity were associated with a high risk of LN metastasis (P < 0.05). The nomogram predicted that the area under the curve was 0.855 (95% CI, 0.794-0.916) and 0.854 (95% CI, 0.727-0.980) in the training and validation cohorts, respectively. In the neoadjuvant therapy group, short diameter, ymrT-stage, internal signal, and MRI-EMVI were associated with LN positivity (P < 0.05), and the area under the curves using the nomogram was 0.912 (95% CI, 0.856-0.968) and 0.915 (95% CI, 0.817-1.000) in two cohorts. The calibration curves demonstrate good agreement between the predicted and actual probabilities for both the training and validation cohorts.

Our nomograms combined with preoperative clinical and imaging biomarkers have the potential to improve the prediction of nodal involvement, which can be used as an essential reference for preoperative N staging and restaging of rectal cancer.

The optimal surgical approach for early-stage rectal cancer remains controversial. Radical resection is considered to be the gold standard for rectal cancer treatment. More and more studies show that local resection can replace traditional radical resection in the treatment of early rectal cancer. This research aimed to compare the efficacy of local excision and radical surgery for early-stage rectal cancer and report the evidence-based clinical advantages of both techniques.

The clinical trials comparing oncological and perioperative local and radical resection outcomes for early-stage rectal cancer were searched from 7 national and international databases.

Finally, 3 randomized controlled trials and 14 cohort studies were included. In terms of oncology and perioperative outcomes, there were no statistically significant differences between the radical resection group and the local resection group in terms of OS (HR = 1.05, 95% CI (0.98, 1.13), DFS [HR = 1.18, 95% CI (0.93, 1.48), p = 0.168), distant metastasis rate (RR = 1.04, 95% CI (0.49, 2.20), p = 0.928), and mortality rate (RR = 1.52, 95% CI (0.80, 2.91), p = 0.200). However, there were significant differences in the outcomes of complications (RR = 2.85, 95% CI (2.07, 3.92), p < 0.001), length of hospital stays (WMD = 5.41, 95% CI (3.94, 6.87), p < 0.001), stoma rate (RR = 7.69, 95% CI (2.39, 24.77), p = 0.001), local recurrence rate (RR = 0.48, 95% CI (0.27, 0.86), p = 0.013), operative time (WMD = 74.68, 95% CI (68.00, 81.36), p < 0.001), blood loss (WMD = 156.36, 95% CI (95.48, 217.21, p < 0.001), and adverse events (RR = 1.59, 95% CI (1.05, 2.41), p = 0.027).

Local excision may be a viable alternative to radical resection for early-stage rectal cancer, but higher quality clinical studies are needed to confirm this.

Preoperative imaging of rectal carcinoma involves accurate assessment of the primary tumor as well as distant metastatic disease. Preoperative imaging of nonrectal colon cancer is most beneficial in identifying distant metastases, regardless of primary T or N stage. Surgical treatment remains the definitive treatment for colon cancer, while organ-sparing approach may be considered in some rectal cancer patients based on imaging obtained before and after neoadjuvant treatment. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Magnetic Resonance Imaging (MRI) is routinely used for preoperative tumor staging and to assess response to therapy in rectal cancer patients. The aim of this study was to evaluate the accuracy of MRI based restaging after neoadjuvant CRT in predicting pathologic response. This multicenter cohort study included adult patients with histologically confirmed locally advanced rectal adenocarcinoma treated with neoadjuvant CRT followed by curative intent elective surgery between January 2014 and December 2019 at four academic high-volume institutions. Magnetic resonance tumor regression grade (mrTRG) and pathologic tumor regression grade (pTRG) were reviewed and compared for all the patients. The agreement between radiologist and pathologist was assessed with the weighted k test. Risk factors for poor agreement were investigated using logistic regression. A total of 309 patients were included. Modest agreement was found between mrTRG and pTRG when regression was classified according to standard five-tier systems (k=0.386). When only two categories were considered for each regression system, (pTRG 0-3 vs. pTRG 4; mrTRG 2-5 vs. mrTRG 1) an accuracy of 78% (IC 95% 0.73-0.83) was found between radiologic and pathologic assessment with a k value of 0.185.The logistic regression model revealed that "T3 greater than 5mm extent" was the only variable significantly impacting on disagreement (OR 0.33, 95% CI 0.15-0.68, p=0.0034). Modest agreement exhists between mrTRG and pTRG. The chances of appropriate assessment of the regression grade after neoadjuvant CRT appear to be higher in case of a T3 tumor with at least 5mm extension in the mesorectal fat at the pre-treatment MRI. This article is protected by copyright. All rights reserved.

Background: Our aim was to compare the bowel function and oncologic outcomes following these two treatment modalities. Materials and methods: This was a single-center study with 67 patients included between 2009 and 2018. A total of 32 patients underwent total mesorectal excision (TME) group and 35 transanal local excisions (LE) ± chemoradiation. We performed a case-matched analysis: we matched the patients by age, cancer stage, and comorbidities. Duration of operation, postoperative complications, length of hospital stay, and long-term functional and oncological outcomes were compared. We calculated oncological outcomes using Kaplan-Meier Cox diagrams. In addition, we used a low anterior resection syndrome (LARS) score for the bowel function assessment. Results: Mean operation time in the LE group was 58.8 ± 45 min compared with the TME group that was 121.1 ± 42 min (p = 0.032). Complications were seen in 5.7% in LE group and 15.62% in TME group (p = 0.043). ~85.2% of the patients had no LARS in LE group compared with 54.5% in TME group (p = 0.018). Minor LARS was 7.4% in LE group compared with 31.8% in TME group (p = 0.018); major LARS was 7.4 and 13.7%, respectively (p = 0.474). Hospital stay was 2.77 days in LE group compared with 9.21 days in TME group (p = 0.036). The overall survival was 68.78 months in LE group compared with 74.81 months in TME group (p = 0.964). Conclusion: Our results of a small sample size showed that local excision ± chemoradiation is a rather safe method for early rectal cancer compared with gold standard treatment. In addition, better bowel function is preserved with less postoperative complications and shorter hospital stays.

According to the main international clinical guidelines, the recommended treatment for locally-advanced rectal cancer is neoadjuvant chemoradiotherapy followed by surgery. However, doubts have been raised about the appropriate definition of clinical complete response (cCR) after neoadjuvant therapy and the role of surgery in patients who achieve a cCR. Surgical resection is associated with significant morbidity and decreased quality of life (QoL), which is especially relevant given the favourable prognosis in this patient subset. Accordingly, there has been a growing interest in alternative approaches with less morbidity, including the organ-preserving watch and wait strategy, in which surgery is omitted in patients who have achieved a cCR. These patients are managed with a specific follow-up protocol to ensure adequate cancer control, including the early identification of recurrent disease. However, there are several open questions about this strategy, including patient selection, the clinical and radiological criteria to accurately determine cCR, the duration of neoadjuvant treatment, the role of dose intensification (chemotherapy and/or radiotherapy), optimal follow-up protocols, and the future perspectives of this approach. In the present review, we summarize the available evidence on the watch and wait strategy in this clinical scenario, including ongoing clinical trials, QoL in these patients, and the controversies surrounding this treatment approach.

Mesorectal lymph node staging plays an important role in treatment decision making. Here, we explore the benefit of higher-order diffusion MRI models accounting for non-Gaussian diffusion effects to classify mesorectal lymph nodes both 1) ex vivo at ultrahigh field correlated with histology and 2) in vivo in a clinical scanner upon patient staging.

The preclinical investigation included 54 mesorectal lymph nodes, which were scanned at 16.4 T with an extensive diffusion MRI acquisition. Eight diffusion models were compared in terms of goodness of fit, lymph node classification ability, and histology correlation. In the clinical part of this study, 10 rectal cancer patients were scanned with diffusion MRI at 1.5 T, and 72 lymph nodes were analyzed with Apparent Diffusion Coefficient (ADC), Intravoxel Incoherent Motion (IVIM), Kurtosis, and IVIM-Kurtosis.

Compartment models including restricted and anisotropic diffusion improved the preclinical data fit, as well as the lymph node classification, compared to standard ADC. The comparison with histology revealed only moderate correlations, and the highest values were observed between diffusion anisotropy metrics and cell area fraction. In the clinical study, the diffusivity from IVIM-Kurtosis was the only metric showing significant differences between benign (0.80 ± 0.30 μm² /ms) and malignant (1.02 ± 0.41 μm² /ms, P = .03) nodes. IVIM-Kurtosis also yielded the largest area under the receiver operating characteristic curve (0.73) and significantly improved the node differentiation when added to the standard visual analysis by experts based on T₂ -weighted imaging.

Higher-order diffusion MRI models perform better than standard ADC and may be of added value for mesorectal lymph node classification in rectal cancer patients.

To analyse changes in post-neoadjuvant follow-up magnetic resonance imaging (MRI) staging accuracy for malignant adenopathies in rectal cancer, by comparing size criteria with morphological criteria using high-resolution T2-weighted sequences, as well as variations when adding diffusion-weighted imaging.

The present study was a cross-sectional study of a database including 46 1.5-T MRI examinations (2011-2016) from patients with biopsy-proven rectal cancer and chemoradiotherapy treatment before surgery. All cases were reviewed by three radiologists individually, who were blinded to any clinical information. The radiologists were experienced in rectal cancer (3-6 years) and evaluated the presence of malignant nodes in each patient. Malignancy was determined using morphological, size (5 mm), and diffusion criteria separately, as well as morphology plus diffusion. Each case was assessed four times: (1) evaluation of morphological criteria; (2) size criteria; (3) evaluation only using diffusion (b-values 50, 400, and 800); and (4) diffusion plus morphological criteria. Histological staging of surgical specimens was the reference standard. Statistical analysis included accuracy (area under the receiver operating characteristic [ROC] curve [AUC]), sensitivity, specificity, and positive/negative predictive values (PPV/NPV) for each radiologist, and group agreement (Fleiss' kappa).

Mean values using morphological criteria were: AUC 0.78, sensitivity 77.7%, specificity 73.8%, PPV 66.1%, NPV 85.2%. Using size criterion: AUC 0.75, sensitivity 62.9%, specificity 83.2%, PPV 74.1%, NPV 80%. Added diffusion yielded no improvement, and yielded worse results by itself.

Although morphological criteria showed better results in accuracy, sensitivity, and NPV, size criterion yielded the best specificity and PPV. Adding diffusion did not demonstrate a clear advantage over the criteria by themselves. Thus, mixed size-morphology criteria could have the greatest diagnostic value for follow-up N-staging.