The sigmoid take-off: An anatomical imaging definition of the rectum validated on specimen analysis

TreatmENT of AnastomotiC LeakagE after colon cancer resection: the TENTACLE - Colon study

BACKGROUND

Anastomotic leakage (AL) is a common and severe complication after colon cancer resection, but studies investigating various treatment strategies and factors influencing outcomes are scarce.

OBJECTIVES

(1) To identify predictive factors associated with 90-day mortality and 90-day Clavien-Dindo grade 4-5 complications amongst patients who developed AL following colon cancer resection with subsequent development and validation of prediction models, and (2) to explore and compare the effectiveness of various treatment strategies for AL following colon cancer resection, adjusting for type of index surgery, different leak entities and patient factors.

METHODS

The TENTACLE - Colon is an international multicentre retrospective cohort study. Consecutive patients with AL after colon cancer resection operated between 1 January 2018 and 31 December 2022 from participating centres will be included. The planned sample size is 2000 patients. The primary outcome is 90-day mortality and the co-primary composite endpoint is Clavien-Dindo grade 4-5 complications. Secondary outcomes include: hospital and intensive care unit length of stay, number of radiological and surgical reinterventions within one year after resection, mortality (in-hospital, 30-day, and 1-year), the comprehensive complication index, and 1-year stoma-free survival. For objective 1, regression models will be used to identify predictors associated with 90-day mortality and grade 4-5 complications. For objective 2, comparative analyses of various treatment strategies will be performed for the specified outcomes, adjusting for patient, tumour, resection and leakage characteristics.

TRIAL REGISTRATION

This study is registered at clinicaltrials.gov (NCT06528054) since July 30th, 2024.

[Surgical anatomy of the anorectum]

The anorectum corresponds to the last segment of the gastrointestinal tract and is responsible for mediating fecal continence and controlled defecation. An understanding of the complex topographic anatomy is an indispensable prerequisite for the surgical treatment of benign and malignant diseases in the anorectal region. The detailed description of perirectal fascia, anorectal blood supply and lymph vessel drainage, pelvic autonomic nerves and components of the anal canal and anal sphincter complex has significantly contributed to improvement of the oncological and functional surgical outcome. In this article the state of knowledge relating to the anorectal anatomy is outlined providing a practical basis for rectal and proctological surgical procedures.

"Sigmoid take-off" to define recto-sigmoid junction and its impact on rectal cancer classification, staging, and management

AIM

The primary objective of this study was to determine the clinical impact of using sigmoid take-off (STO) in the management of rectal cancer. We also evaluated the inter-observer reliability in the identification of STO.

MATERIAL AND METHODS

This retrospective study reviewed staging MRI of patients with mid and high-rectal cancers performed between January 2019 and December 2022. The location of the tumour was reclassified based on STO as defined by D'Souza et al. (2018) and compared with the location determined based on distance from the anal verge. The proportions of cases that show a change in tumour location from rectal cancer to sigmoid cancer and the potential change in treatment were noted. The interobserver agreement for the location of STO and the location of tumours from STO was studied among four subspecialised abdominal radiologists.

RESULTS

Out of 134 rectal cancer patients included, STO-based assessment resulted in the reclassification of 13.4% (n=18) cases into sigmoid cancer. There was, however, no change in the stage of cancer. Among these 18 patients, there would have been a change in management in 5 patients had the initial assessment been a sigmoid cancer. There was excellent agreement among the radiologists for measuring the distance of STO from the anal verge (ICC = 0.883, p<0.001) and determining the location of the tumour based on STO (K = 0.82, p<0.001).

CONCLUSIONS

Using STO changed the location of tumours in 13.4% of high- and mid-rectal cancers. There was excellent agreement among radiologists regarding determining STO and identifying tumour locations using STO.

The Surgical Management of the Mesentery in Crohn's Disease

Increasing evidence suggests that Crohn's disease is a primary mesenteropathy and that resection of the mesentery, or its exclusion from an anastomosis, may alter disease progression. If borne out in clinical trials, this observation would be welcome, as current pharmacotherapeutic approaches to Crohn's disease appear to have limited effect on disease progression. This article explores arguments for and against the alteration of mesenteric inputs by surgical means, in Crohn's disease.

Oncological outcome following Hartmann's procedure compared with anterior resection and abdominoperineal resection for rectal cancer-The type of procedure does not influence local recurrence or distant metastasis: A population-based study

AIM

The type of surgical procedure used in rectal cancer treatment may affect cancer recurrence. The aim of this study was to determine whether the type of procedure influences oncological outcomes in rectal cancer surgery.

METHOD

We gathered data from the Swedish Colorectal Cancer Registry regarding patients with TNM Stage I-III rectal cancer who underwent R0/R1 surgery from 2013 to 2017. The outcomes after Hartmann's procedure (HP), anterior resection (AR) and abdominoperineal resection (APR) were compared, and a multivariable Cox regression analysis was performed. The primary outcome of the study was the local recurrence rate. The secondary outcomes were distant metastasis, disease-free survival and overall survival at 5 years as well as risk factors for local recurrence.

RESULTS

A total of 4741 patients were included in the study: 614 underwent HP, 3075 underwent AR and 1052 underwent APR. Multivariable Cox regression revealed no difference in local recurrence, distant metastasis or disease-free survival. Overall survival was higher following AR (OR 0.62, CI 0.54-0.72). Risk factors for local recurrence were intraoperative bowel perforation (OR 2.41, CI 1.33-4.40), a pT4 tumour (OR 1.93, CI 1.11-3.4) and a positive circumferential resection margin (OR 5.62, CI 3.28-9.61).

CONCLUSIONS

This nationwide study showed that the type of procedure did not affect the local recurrence rate or distant metastasis. In patients who are unfit for restorative surgery, HP is a viable alternative with oncological outcomes similar to those of APR.

MRI for Rectal Cancer: Updates and Controversies-AJR Expert Panel Narrative Review

Rectal MRI is a critical tool in the care of patients with rectal cancer, having established roles for primary staging, restaging, and surveillance. The comprehensive diagnostic and prognostic information provided by MRI helps to optimize treatment decision-making. However, challenges persist in the standardization and interpretation of rectal MRI, particularly in the context of rapidly evolving treatment paradigms, including growing acceptance of nonoperative management. In this AJR Expert Panel Narrative Review, we address recent advances and key areas of contention relating to the use of MRI for rectal cancer. Our objectives include: to discuss concepts regarding anatomic localization of rectal tumors; review the evolving rectal cancer treatment paradigm and implications for MRI assessment; discuss updates and controversies regarding rectal MRI for locoregional staging, restaging, and surveillance; review current rectal MRI acquisition protocols; and discuss challenges in homogenizing and optimizing acquisition parameters.

Colorectal cancer

Despite decreased incidence rates in average-age onset patients in high-income economies, colorectal cancer is the third most diagnosed cancer in the world, with increasing rates in emerging economies. Furthermore, early onset colorectal cancer (age ≤50 years) is of increasing concern globally. Over the past decade, research advances have increased biological knowledge, treatment options, and overall survival rates. The increase in life expectancy is attributed to an increase in effective systemic therapy, improved treatment selection, and expanded locoregional surgical options. Ongoing developments are focused on the role of sphincter preservation, precision oncology for molecular alterations, use of circulating tumour DNA, analysis of the gut microbiome, as well as the role of locoregional strategies for colorectal cancer liver metastases. This overview is to provide a general multidisciplinary perspective of clinical advances in colorectal cancer.

Anatomic Basis of Rectal Cancer Staging: Clarifying Controversies and Misconceptions

Rectal MRI provides a detailed depiction of pelvic anatomy; specifically, the relationship of the tumor to key anatomic structures, including the mesorectal fascia, anterior peritoneal reflection, and sphincter complex. However, anatomic inconsistencies, pitfalls, and confusion exist, which can have a strong impact on interpretation and treatment. These areas of confusion include the definition of the rectum itself, specifically differentiation of the rectum from the anal canal and the sigmoid colon, and delineation of the high versus low rectum. Other areas of confusion include the relative locations of the mesorectal fascia and peritoneum and their significance in staging and treatment, the difference between the mesorectal fascia and circumferential resection margin, involvement of the sphincter complex, and evaluation of lateral pelvic lymph nodes. The impact of these anatomic inconsistencies and sources of confusion is significant, given the importance of MRI in depicting the anatomic relationship of the tumor to critical pelvic structures, to triage surgical resection and neoadjuvant chemoradiotherapy with the goal of minimizing local recurrence. Evolving treatment paradigms also place MRI central in management of rectal cancer. ©RSNA, 2024.

Diagnostic Benefits and Surgical Implications of Methods for Tumor Localization in Sigmoid and Rectum Tumors

(1) Background: In our study, we aimed to determine the accuracy rates of imaging methods for sigmoid, rectosigmoid colon, and rectum cancer. (2) Methods: Patients with tumors located in the rectosigmoid colon, sigmoid colon, and rectum who were operated on were included. Upon admission, we examined the patients' first diagnostic colonoscopies and their preoperative repeat control colonoscopies and computed tomography (CT) report. (3) Results: In this study, 23 patients (57.5%) were male. The overall accuracy rates were 80.0% (32/40) in colonoscopy, 65.0% (26/40) in preoperative CT, and 87.5% (35/40) in retro CT, and the differences among the examination methods were statistically significant (p = 0.049). The sensitivity levels decreased to 50.0% for colonoscopy and preoperative CT and 75.0% for retro CT in rectosigmoid colon tumors. In rectal tumors, the sensitivity levels were 75.0% in colonoscopy, 60.0% in preoperative CT, and 80.0% in retro CT. In two patients, the tumor location was given incorrectly, and postoperative pathological evaluations indicated T3N0 tumors; the initially planned treatment was thus changed to include radiotherapy in addition to chemotherapy in the postoperative period because the tumor was located in the middle rectum. (4) Conclusions: Accuracy in tumor localization in sigmoid, rectosigmoid, and rectum tumors still needs to be improved, which could be accomplished with prospective studies. CT evaluations for cancer localization in this patient group should be re-evaluated by a radiologist.

Long-Term Outcomes of Robotic Versus Laparoscopic Total Mesorectal Excisions: A Propensity-Score Matched Cohort study of 5-year survival outcomes

Objective

To compare long-term outcomes between laparoscopic and robotic total mesorectal excisions (TMEs) for rectal cancer in a tertiary center.

Background

Laparoscopic rectal cancer surgery has comparable long-term outcomes to the open approach, with several advantages in short-term outcomes. However, it has significant technical limitations, which the robotic approach aims to overcome.

Methods

We included patients undergoing laparoscopic and robotic TME surgery between 2013 and 2021. The groups were compared after propensity-score matching. The primary outcome was 5-year overall survival (OS). Secondary outcomes were local recurrence (LR), distant recurrence (DR), disease-free survival (DFS), and short-term surgical and patient-related outcomes.

Results

A total of 594 patients were included, and after propensity-score matching 215 patients remained in each group. There was a significant difference in 5-year OS (72.4% for laparoscopy vs 81.7% for robotic, P = 0.029), but no difference in 5-year LR (4.7% vs 5.2%, P = 0.850), DR (16.9% vs 13.5%, P = 0.390), or DFS (63.9% vs 74.4%, P = 0.086). The robotic group had significantly less conversion (3.7% vs 0.5%, P = 0.046), shorter length of stay [7.0 (6.0-13.0) vs 6.0 (4.0-8.0), P < 0.001), and less postoperative complications (63.5% vs 50.7%, P = 0.010).

Conclusions

This study shows a correlation between higher 5-year OS and comparable long-term oncological outcomes for robotic TME surgery compared to the laparoscopic approach. Furthermore, lower conversion rates, a shorter length of stay, and a less minor postoperative complications were observed. Robotic rectal cancer surgery is a safe and favorable alternative to the traditional approaches.

Total mesorectal excision in MRI-defined low rectal cancer: multicentre study comparing oncological outcomes of robotic, laparoscopic and transanal total mesorectal excision in high-volume centres

BACKGROUND

The routine use of MRI in rectal cancer treatment allows the use of a strict definition for low rectal cancer. This study aimed to compare minimally invasive total mesorectal excision in MRI-defined low rectal cancer in expert laparoscopic, transanal and robotic high-volume centres.

METHODS

All MRI-defined low rectal cancer operated on between 2015 and 2017 in 11 Dutch centres were included. Primary outcomes were: R1 rate, total mesorectal excision quality and 3-year local recurrence and survivals (overall and disease free). Secondary outcomes included conversion rate, complications and whether there was a perioperative change in the preoperative treatment plan.

RESULTS

Of 1071 eligible rectal cancers, 633 patients with low rectal cancer were identified. Quality of the total mesorectal excision specimen (P = 0.337), R1 rate (P = 0.107), conversion (P = 0.344), anastomotic leakage rate (P = 0.942), local recurrence (P = 0.809), overall survival (P = 0.436) and disease-free survival (P = 0.347) were comparable among the centres. The laparoscopic centre group had the highest rate of perioperative change in the preoperative treatment plan (10.4%), compared with robotic expert centres (5.2%) and transanal centres (2.1%), P = 0.004. The main reason for this change was stapling difficulty (43%), followed by low tumour location (29%). Multivariable analysis showed that laparoscopic surgery was the only independent risk factor for a change in the preoperative planned procedure, P = 0.024.

CONCLUSION

Centres with expertise in all three minimally invasive total mesorectal excision techniques can achieve good oncological resection in the treatment of MRI-defined low rectal cancer. However, compared with robotic expert centres and transanal centres, patients treated in laparoscopic centres have an increased risk of a change in the preoperative intended procedure due to technical limitations.

Sigmoid take-off in rectosigmoid cancer as a landmark identifying benefit from neoadjuvant chemoradiation: A retrospective comparative cohort study

INTRODUCTION

There is no standard treatment strategy for rectosigmoid cancer because of the diverse definitions of the proximal rectal origin. This study aimed to evaluate sigmoid take-off compared with other landmarks of the rectosigmoid junction in guiding oncological therapy and outcomes.

MATERIALS AND METHODS

This retrospective, comparative cohort study included patients diagnosed with rectosigmoid carcinoma at our centre between January 2010 and December 2018. The patients were classified into the neoadjuvant treatment group and upfront surgery group. The oncological outcomes were compared between the two groups in relation to the tumor position.

RESULTS

A total of 656 patients (median age 64 years) were included. After propensity score matching, the 3- and 5-year overall survival and disease-free survival in patients in both the groups were comparable. However, when only patients with rectal cancer as defined by the sigmoid take-off point were included, the disease-free survival rate in the upfront surgery group was significantly lower than that in the neoadjuvant treatment group (p = 0.03 in patients who underwent computed tomography, p = 0.03 in patients who underwent magnetic resonance imaging). The turning point of the beneficial hazard ratio of neoadjuvant therapy was compared according to the different definitions of the rectosigmoid junction and the sigmoid take-off was found to be the most effective.

CONCLUSION

The sigmoid take-off point is a suitable landmark for identifying the rectosigmoid junction and is an important defining criterion for assessing the benefit of neoadjuvant therapy. The application of this definition in clinical practice and future trials is warranted.

Rectal cancer lexicon 2023 revised and updated consensus statement from the Society of Abdominal Radiology Colorectal and Anal Cancer Disease-Focused Panel

The Society of Abdominal Radiology's Colorectal and Anal Cancer Disease-Focused Panel (DFP) first published a rectal cancer lexicon paper in 2019. Since that time, the DFP has published revised initial staging and restaging reporting templates, and a new SAR user guide to accompany the rectal MRI synoptic report (primary staging). This lexicon update summarizes interval developments, while conforming to the original lexicon 2019 format. Emphasis is placed on primary staging, treatment response, anatomic terminology, nodal staging, and the utility of specific sequences in the MRI protocol. A discussion of primary tumor staging reviews updates on tumor morphology and its clinical significance, T1 and T3 subclassifications and their clinical implications, T4a and T4b imaging findings/definitions, terminology updates on the use of MRF over CRM, and the conundrum of the external sphincter. A parallel section on treatment response reviews the clinical significance of near-complete response and introduces the lexicon of "regrowth" versus "recurrence". A review of relevant anatomy incorporates updated definitions and expert consensus of anatomic landmarks, including the NCCN's new definition of rectal upper margin and sigmoid take-off. A detailed review of nodal staging is also included, with attention to tumor location relative to the dentate line and locoregional lymph node designation, a new suggested size threshold for lateral lymph nodes and their indications for use, and imaging criteria used to differentiate tumor deposits from lymph nodes. Finally, new treatment terminologies such as organ preservation, TNT, TAMIS and watch-and-wait management are introduced. This 2023 version aims to serve as a concise set of up-to-date recommendations for radiologists, and discusses terminology, classification systems, MRI and clinical staging, and the evolving concepts in diagnosis and treatment of rectal cancer.

Completion Total Mesorectal Excision: A Case-Matched Comparison With Primary Resection

Objectives

The aim of this study was to compare the perioperative and oncological results of completion total mesorectal excision (cTME) versus primary total mesorectal excision (pTME).

Background

Early-stage rectal cancer can be treated by local excision alone, which is associated with less surgical morbidity and improved functional outcomes compared with radical surgery. When high-risk histological features are present, cTME is indicated, with possible worse clinical and oncological outcomes compared to pTME.

Methods

This retrospective cohort study included all patients that underwent TME surgery for rectal cancer performed in 11 centers in the Netherlands between 2015 and 2017. After case-matching, we compared cTME with pTME. The primary outcome was major postoperative morbidity. Secondary outcomes included the rate of restorative procedures and 3-year oncological outcomes.

Results

In total 1069 patients were included, of which 35 underwent cTME. After matching (1:2 ratio), 29 cTME and 58 pTME were analyzed. No differences were found for major morbidity (27.6% vs 19.0%; P = 0.28) and abdominoperineal excision rate (31.0% vs 32.8%; P = 0.85) between cTME and pTME, respectively. Local recurrence (3.4% vs 8.6%; P = 0.43), systemic recurrence (3.4% vs 12.1%; P = 0.25), overall survival (93.1% vs 94.8%; P = 0.71), and disease-free survival (89.7% vs 81.0%; P = 0.43) were comparable between cTME and pTME.

Conclusions

cTME is not associated with higher major morbidity, whereas the abdominoperineal excision rate and 3-year oncological outcomes are similar compared to pTME. Local excision as a diagnostic tool followed by completion surgery for early rectal cancer does not compromise outcomes and should still be considered as the treatment of early-stage rectal cancer.

Excessive bowel volume loss during anus-preserving surgery for rectal cancer affects the bowel function after operation: A prospective observational cohort study (Bas-1611)

Background

Bowel volume loss during anus-preserving surgery (APS) may result in low anterior resection syndrome (LARS). We conducted this prospective observational cohort study to measure the incidence of LARS after surgery and evaluate the relationship between bowel volume loss and bowel function.

Methods

Patients with R0 resectable rectal cancer who consented to several bowel function surveys through telephone interviews after the operation were included. Enrolled patients underwent standard APS for rectal cancer, and three length indexes, viz. length of excised bowel, length of the distal margin and length of the proximal margin (LPM) of fresh bowel specimens, were measured in vitro.

Results

The three measured variables of the specimens showed a positively skewed distribution. Patient interviews revealed a trend of gradual improvement in bowel function. Univariate analyses revealed that longer LPM was associated with a significantly negative impact on bowel function at all time points. In multivariate analysis, LPM was found to be a significant risk factorstatistically significant, but its impact was not as strong as that of radiotherapy and low-middle tumour. Furthermore, there was no significant difference in the lymph node detection rate between <10-cm and ≥10-cm LPM groups.

Conclusion

In APS for rectal cancer, bowel volume loss is an important factor causing postoperative bowel dysfunction. Controlling LPM to <10 cm may help improve postoperative bowel function.

A Cost Overview of Minimally Invasive Total Mesorectal Excision in Rectal Cancer Patients: A Population-based Cohort in Experienced Centres

Background

Total mesorectal excision has been the gold standard for the operative management of rectal cancer. The most frequently used minimally invasive techniques for surgical resection of rectal cancer are laparoscopic, robot-assisted, and transanal total mesorectal excision. As studies comparing the costs of the techniques are lacking, this study aims to provide a cost overview.

Method

This retrospective cohort study included patients who underwent total mesorectal resection between 2015 and 2017 at 11 dedicated centers, which completed the learning curve of the specific technique. The primary outcome was total in-hospital costs of each technique up to 30 days after surgery including all major surgical cost drivers, while taking into account different team approaches in the transanal approach. Secondary outcomes were hospitalization and complication rates. Statistical analysis was performed using multivariable linear regression analysis.

Results

In total, 949 patients were included, consisting of 446 laparoscopic (47%), 306 (32%) robot-assisted, and 197 (21%) transanal total mesorectal excisions. Total costs were significantly higher for transanal and robot-assisted techniques compared to the laparoscopic technique, with median (interquartile range) for laparoscopic, robot-assisted, and transanal at €10,556 (8,642;13,829), €12,918 (11,196;16,223), and € 13,052 (11,330;16,358), respectively (P < 0.001). Also, the one-team transanal approach showed significant higher operation time and higher costs compared to the two-team approach. Length of stay and postoperative complications did not differ between groups.

Conclusion

Transanal and robot-assisted approaches show higher costs during 30-day follow-up compared to laparoscopy with comparable short-term clinical outcomes. Two-team transanal approach is associated with lower total costs compared to the transanal one-team approach.

The Mesentery-Past, Present, and Future

This article summarizes the events that shaped our current understanding of the mesentery and the abdomen. The story of how this evolved is intriguing at several levels. It speaks to considerable personal commitment on the part of the pioneers involved. It explains how scientific and clinical fields went different directions with respect to anatomy and clinical practice. It demonstrates that it is no longer acceptable to adhere unquestioningly to models of abdominal anatomy and surgery. The article concludes with a brief description of the Mesenteric Model of abdominal anatomy, and of how this now presents an opportunity to unify scientific and clinical approaches to the latter.

Interobserver Reliability and the Sigmoid Takeoff—An Interobserver Study

Simple Summary

Colorectal cancer is the second most common cancer. The sigmoid takeoff is the landmark where the colon sigmoid curves toward the sacrum viewed from sagittal magnetic resonance imaging. We assessed the interobserver variability in the assessment of the anal verge and anorectal junction in patients diagnosed with rectal cancer using magnetic resonance imaging. Our data indicate that radiologists are excellent at pointing out if a colorectal tumour is above or beneath the takeoff landmark.

Abstract

Background: Colorectal cancer is the second most common cancer worldwide. The sigmoid takeoff is the landmark where the colon sigmoid curves toward the sacrum viewed from sagittal magnetic resonance imaging (MRI). The purpose of this study was to assess interobserver variability in the assessment of the anal verge and anorectal junction in patients diagnosed with rectal cancer on magnetic resonance imaging (MRI). Materials and Methods: The rectal MRI examinations were performed using a 1.5- or 3.0-tesla unit using an anterior coil and a standard scan protocol. Two senior radiologists assessed MRI scans from patients under investigation for rectal cancer. The two observers assessed the anal verge and takeoff in cm independently. Difference in agreement between the observers were evaluated using intraclass correlation (ICC) and graphically by Bland–Altman plots. Results: The study population (n = 122) included 68 (55.7%) female and 54 (44.3%) male subjects. The overall median age was 69.5 years (range 39–95 years). There was perfect agreement between the two observers when defining rectal tumor above or below the takeoff landmark. The reliability of measuring the distance from the anal verge to the sigmoid takeoff was 0.712. Conclusion: Overall, the study found a moderate reliability in assessing the location of the sigmoid takeoff, with a low difference in the distance measuring, as well as a good consensus concerning the determination of tumors in relation to the sigmoid takeoff. Routine implementation of this information within the report seems reasonable.

MRI-detected extramural vascular invasion (mrEMVI) as the best predictive factor to identify candidates to total neoadjuvant therapy in locally advanced rectal cancer

BACKGROUND AND OBJECTIVES

Chemotherapy in locally advanced rectal cancer (LARC) is shifting from an adjuvant setting to a total neoadjuvant therapy (TNT) strategy, that relies on distant metastases (DM) risk prediction. This study aims to assess the accuracy of magnetic resonance imaging-detected extramural vascular invasion (mrEMVI) as predictive factor for DM in LARC, compared with other MRI-detected and pathologic factors.

METHODS

This retrospective single-center study analyzed data extracted from a series of consecutive patients curatively resected for rectal cancer at Mauriziano Hospital in Turin (Italy) from January 2013 to December 2018.

RESULTS

Data from 69 patients were analyzed. MrEMVI was detected in 31 (44.9%) cases. Median follow-up was 39.9 months. DM and local recurrence occurred in 19 (27.5%) and 4 (5.8%) patients. One- and 3-year cumulative incidence of DM were 32.3% (95% confidence interval [CI]: 0.17-0.49) and 56.8% (95% CI: 0.35-0.74) in the mrEMVI-positive group and 5.4% (95% CI: 0.01-0.16) and 14.0% (95% CI: 0.05-0.27) in the mrEMVI-negative group (log-rank test, p < 0.001). In the multivariate analysis of MRI factors, mrEMVI was the only independent predictor of DM (HR: 3.59, CI: 1.21-10.69, p = 0.02).

CONCLUSIONS

This study confirmed that mrEMVI is a powerful predictor of DM in LARC. It should be routinely reported and considered during multidisciplinary care strategy planning.

The importance of MRI for rectal cancer evaluation

Magnetic resonance imaging (MRI) has gained increasing importance in the management of rectal cancer over the last two decades. The role of MRI in patients with rectal cancer has expanded beyond the tumor-node-metastasis (TNM) system in both staging and restaging scenarios and has contributed to identifying "high" and "low" risk features that can be used to tailor and personalize patient treatment; for instance, selecting the patients for neoadjuvant chemoradiation (NCRT) before the total mesorectal excision (TME) surgery based on risk of recurrence. Among those features, the status of the circumferential resection margin (CRM), extramural vascular invasion (EMVI), and tumor deposits (TD) have stood out. Moreover, MRI also has played a role in surgical planning, especially when the tumor is located in the low rectum, when the relationship between tumor and the anal canal is important to choose the best surgical approach, and in cases of locally advanced or recurrent tumors invading adjacent pelvic organs that may require more complex surgeries such as pelvic exenteration. As approaches using organ preservation emerge, including transanal local excision and "watch-and-wait", MRI may help in the patient selection for those treatments, follow up, and detection of tumor regrowth. Additionally, potential MRI-based prognostic and predictive biomarkers, such as quantitative and semi-quantitative metrics derived from functional sequences like diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE), and radiomics, are under investigation. This review provides an overview of the current role of MRI in rectal cancer in staging and restaging and highlights the main areas under investigation and future perspectives.

Evaluation of the implementation of the sigmoid take-off landmark in the Netherlands

AIM

The sigmoid take-off (STO), the point on imaging where the sigmoid sweeps ventral from the sacrum, was chosen as the definition of the rectum during an international Delphi consensus meeting and has been incorporated into the Dutch guidelines since October 2019. The aim of this study was to evaluate the implementation of this landmark 1 year after the guideline implementation and to perform a quality assessment of the STO training.

METHOD

Dutch radiologists, surgeons, surgical residents, interns, PhD students and physician assistants were asked to complete a survey and classify 20 tumours on MRI as 'below', 'on' or 'above' the STO. Outcomes were agreement with the expert reference, inter-rater variability and accuracy before and after the training.

RESULTS

Eighty-six collaborators participated. Six radiologists (32%) and 11 surgeons (73%) used the STO as the standard landmark to distinguish between rectal and sigmoidal tumours during multidisciplinary meetings. Overall agreement with the expert reference improved from 53% to 70% (p < 0.001) after the training. The positive predictive value for diagnosing rectal tumours was high before and after the training (92% vs. 90%); the negative predictive value for diagnosing sigmoidal tumours improved from 39% to 63%.

CONCLUSION

Approximately half of the represented hospitals have implemented the new definition of rectal cancer 1 year after the implementation of the Dutch national guidelines. Overall baseline agreement with the expert reference and accuracy for the tumours around the STO was low, but improved significantly after training. These results highlight the added value of training in implementation of radiological landmarks to ensure unambiguous assessment.

Influence of Minimally Invasive Resection Technique on Sphincter Preservation and Short-term Outcome in Low Rectal Cancer in the Netherlands

BACKGROUND

Transanal and robotic-assisted total mesorectal excision are techniques that can potentially overcome challenges encountered with a pure laparoscopic approach in patients with rectal cancer.

OBJECTIVE

The aim of this study was to evaluate the proportion and predictive factors of restorative procedures and subsequent short-term outcomes of 3 minimally invasive techniques to treat low rectal cancer.

DESIGN

This is a nationwide observational comparative registry study.

SETTINGS

Patients with rectal cancer were selected from the mandatory Dutch ColoRectal Audit.

PATIENTS

Patients with low rectal cancer (≤5 cm) who underwent curative minimally invasive total mesorectal excision between 2015 and 2018 were included.

MAIN OUTCOME MEASURES

The primary outcomes measured were the proportion of restorative procedure, positive circumferential resection margin, and postoperative complications.

RESULTS

A total of 3466 patients were included for analysis, of which 33% underwent a restorative procedure. Resections were performed laparoscopically in 2845 patients, transanally in 448 patients, and were robot-assisted in 173 patients, with a proportion of restorative procedures of 28%, 66%, and 40%. The transanal approach was independently associated with a restorative procedure (OR, 4.11; 95% CI, 3.21-5.26; p < 0.001). Independent risk factors for a nonrestorative procedure, irrespective of the surgical technique, were age >75 years, ASA physical status ≥3, BMI >30, history of abdominal surgery, clinical T4-stage, mesorectal fascia ≤1 mm, neoadjuvant therapy, and having a procedure in 2015 to 2016 versus 2017 to 2018. The circumferential resection margin involvement was similar for all 3 groups (5.4%, 5.1%, and 5.1%). Short-term postoperative complications were less favorable for the newer techniques than for the laparoscopic approach.

LIMITATIONS

This study was limited because of the registry's variables and different group sizes.

CONCLUSION

Patients with low rectal cancer in the Netherlands are more likely to receive a restorative procedure with a transanal approach, compared with a laparoscopic or robotic procedure. Short-term oncological outcomes are comparable between the 3 minimally invasive techniques. See Video Abstract at http://links.lww.com/DCR/B608.

INFLUENCIA DE LA TCNICA DE RESECCIN MINIMAMENTE INVASIVA CON PRESERVACIN DE ESFNTERES EN LA RESOLUCIN A CORTO PLAZO EN CANCER DE TERCIO INFERIOR DE RECTO EN LOS PASES BAJOS

ANTECEDENTES:La excisión mesorrectal transanal y asistida por robot son técnicas que potencialmente pueden superar algunos obstáculos que podemos encontrar en un abordaje exclusivamente laparoscópico en pacientes con cáncer de recto.OBJECTIVOS:El objetivo de este estudio es evaluar la proporción y los factores de predicción positivos de los procedimientos restauradores y los resultados subsecuentes a corto plazo de tres técnicas mínimamente invasivas para tratar el cáncer de tercio inferior de recto.DISEÑO:Es un estudio comparativo observacional del registro nacional.ESCENARIO:Pacientes con cáncer de recto seleccionados del Registro Oficial de la Auditoría Holandesa Colo-rectal.PACIENTGES:Pacientes con cáncer de tercio inferior de recto (≤5 centimetros) sometidos a excision mesorrectal total mínimamente invasiva curativa.PRINCIPALES PARAMETROS DE EFECTIVIDAD:Proporción de procedimientos restauradores, margen de resección circunferencial positivo y complicaciones postoperatorias.RESULTADOS:Se incluyeron un total de 3,466 pacientes para análisis, de los cuales 33% fueron sometidos a procedimiento restaurador. Las resecciones fueron laparoscópica en 2,845 pacientes, transanal en 448 y asistidas por robot en 173, con una proporción de procedimientos restauradores en 28%, 66% y 40% respectivamente. El abordaje transanal se correlacionó en forma independiente con el procedimiento restaurador (OR 4.11; 95% CI 4.11; 95% CI 3.21-5.26; p<0.001). Los factores de riesgo independientes para un procedimiento no restaurador, sin tomar en cuenta la técnica quirúrgica fueron: edad >75, American Society of Anesthesiologist ≥3, índice de masa corporal >30, antecedente de cirugía abdominal, Estadio clínico T4, fascia mesorrectal ≤1 millimetro, terapia neoadyuvante y haber sido sometido al procedimiento en 2015-2016 y no en 2017-2018. El margen circunferencial de resección involucrado fue similar para los tres grupos (5.4%, 5.1% y 5.1%). Las complicaciones postquirúrgicas a corto plazo fueron menos favorables para las técnicas nuevas comparadas con el abordaje laparoscópico.LIMTANTES:El estudio tiene la limitación de las variables dependientes del registro y la diferencia entre el número de pacientes en cada grupo.CONCLUSION:Los pacientes con cáncer de tercio inferior de recto en Holanda se tratan con mayor frecuencia mediante un procedimiento restaurador transanal en comparación con los abordajes laparoscópico o robótico. Los resultados favorables desde el punto de vista oncológico a corto plazo son comparables entre las tres técnicas de invasión mínima. Consulte Video Resumenhttp://links.lww.com/DCR/B608.

Local recurrence in sigmoid cancer is a hidden problem, could CT prognostic factors be of value in their prevention? A multi-centre study of 414 patients

INTRODUCTION

The incidence and patterns of local recurrence of colon cancer are not well reported. The aim of this study was to investigate the contemporary rates and patterns of local recurrence after sigmoid cancer resection, comparing pre and post-operative biomarkers in predicting local disease recurrence.

MATERIALS AND METHODS

A multi-centre, retrospective analysis of 414 patients undergoing resectional surgery for sigmoid colon cancer was conducted. Multivariable Cox Proportional Hazard models were created to identify variables associated with local disease recurrence. Patterns of recurrence and prognostic significance of pre and post-operative variables were identified.

RESULTS

In 414 patients, the local recurrence rate was 12.6%. The R1/R2 rate was 2.4%. Local recurrence occurred most commonly within the peri-anastomotic region (50%), followed by the peritoneum (33%). On multivariate analysis, local recurrence was predicted by pathological T stage (HR 1.15) and R1 resection (HR 2.95), but also computerised tomography (CT) identified tumour deposits (HR 2.40) and local peritoneal infiltration (2.70).

CONCLUSIONS

Contemporary local recurrence rates for sigmoid cancer are high at 12.6%. Outcomes may be improved if local recurrence is reduced at the most common sites such as the peri-anastomotic area or peritoneum. Extra-nodal CT-imaging biomarkers of local peritoneal infiltration and tumour deposits were prognostically significant on multivariate analysis in addition to pathology staging variables.

MRI of rectal cancer-relevant anatomy and staging key points

Rectal cancer has the eighth highest cancer incidence worldwide, and it is increasing in young individuals. However, in countries with a high human development index, mortality is decreasing, which may reflect better patient management, imaging being key. We rely on imaging to establish the great majority of clinical tumour features for therapeutic decision-making, namely tumour location, depth of invasion, lymph node involvement, circumferential resection margin status and extramural venous invasion. Despite major improvements in technique resulting in better image quality, and notwithstanding the dissemination of guidelines and examples of standardised reports, rectal cancer staging is still challenging on the day-to-day practice, and we believe there are three reasons. First, the normal posterior pelvic compartment anatomy and variants are not common knowledge to radiologists; second, not all rectal cancers fit in review paper models, namely the very early, the very low and the mucinous; and third, the key clinical tumour features may be tricky to analyse. In this review, we discuss the normal anatomy of the rectum and posterior compartment of the pelvis, systematise all rectal cancer staging key points and elaborate on the particularities of early, low and mucinous tumours. We also include our suggested reporting templates and a discussion of its comparison to the reporting templates provided by ESGAR and SAR.

Comparison of the sigmoid take-off with other definitions of the rectosigmoid junction: A retrospective comparative cohort analysis

BACKGROUND

The diversity in definitions for the rectosigmoid junction is becoming a major obstacle in standardizing optimal treatment of rectal cancers. The study aimed to determine the average distance of the sigmoid take-off from the anal verge and its association with individual factors.

MATERIALS AND METHODS

Patients diagnosed with rectal and sigmoid colon cancer in our centre from January 2010 to December 2018 were retrospectively enrolled in the cancer group. The results of 200 controls without colorectal disease were also reviewed (normal group). The distance of different landmarks and margins of cancer from the anal verge were retrieved from computed tomography (CT), magnetic resonance imaging (MRI), and endoscopy findings.

RESULTS

The cancer group comprised 635 patients (381 men, median age: 64 years). The average distances of the sigmoid take-off from the anal verge measured in CT and MRI were comparable (P = 0.483). On MRI, the average distance of the sigmoid take-off from the anal verge in the cancer group was comparable with that of the normal group (P = 0.070). Multivariate regression revealed that the distance of the sigmoid take-off from the anal verge was associated with the distances of the sacral promontory (P < 0.001) and peritoneal reflection (P < 0.001) from the anal verge.

CONCLUSION

The cancer distributions of patients varied widely with the application of different definitions. The point of sigmoid take-off is an intuitive landmark influenced by individual factors. The measurement of the sigmoid take-off by different researchers in both CT and MRI revealed good consistency. Further studies regarding the clinical significance of this definition are still needed.