The clinical significance of a pathologically positive lymph node at the circumferential resection margin in rectal cancer

The mode of circumferential margin involvement in rectal cancer determines its impact on outcomes: A population-based study

BACKGROUND

The clinical value of different modes of CRM involvement in rectal cancer patients is unclear. This study aims to determine the clinical impact of different modes of circumferential resection margin (CRM) involvement in patients with a locally advanced rectal carcinoma.

PATIENTS AND METHODS

A cohort of patients who were diagnosed with stage III rectal cancer between June 2014 and June 2020 was selected from the prospective Dutch nationwide pathology databank (PALGA). Histopathological and clinical data were analyzed according to the nature of CRM involvement (via primary tumor invasion, lymph node metastasis, tumor deposit, multiple factors) and analyses on recurrence and overall survival (OS) were performed.

RESULTS

3020 patients were included, of whom 12.4 % had a positive CRM. The majority of these patients (63.2 %) had CRM involvement by primary tumor invasion and in 9 % of patients multiple factors caused the positive CRM. The rates of local recurrence and distant metastasis were related to the nature of the CRM involvement, with lowest rate for lymph node metastasis and highest rate for multiple factors. On multivariate analysis, CRM involvement by primary tumor invasion, tumor deposits and multiple factors, but not by lymph node metastasis, were associated with poor OS.

CONCLUSION

This nationwide population based study highlights the clinical importance of reporting the nature of CRM involvement in rectal cancer patients. Lymph node metastasis involving the CRM does not bear the same risks for local recurrence, distant metastases and OS as CRM involvement by primary tumor invasion or CRM involvement by multiple factors.

Circumferential resection margin positivity due to direct or indirect tumour involvement in rectal cancer - a call for better stratification

BACKGROUND

A positive circumferential resection margin (CRM) after rectal cancer surgery, which can be the result of direct or indirect tumour involvement, has consistently been associated with increased local recurrence and poorer survival. However, little is known of the differential impact of the mode of tumour involvement on outcomes.

METHODS

1460 consecutive patients undergoing rectal cancer resection between 2003 and 2018 were retrospectively assessed. Histopathology reports for patients with a positive CRM were reviewed to determine cases of direct (R1-tumour) or indirect tumour involvement (R1-other). Disease-free survival (DFS) and overall survival (OS) were assessed by Kaplan-Meier analysis. The role of the mode of CRM positivity was examined by univariate and multivariate Cox proportional hazards models.

RESULTS

Eighty-five patients had an R1 resection due to CRM involvement (5.8%). Of those, 69 were due to direct tumour involvement, while 16 were from indirect causes. Kaplan-Meier analysis revealed that R1-other was associated with increased OS (hazard ratio 0.40, log-rank P = 0.006) and DFS (P = 0.043). Multivariate regression confirmed that the mode of CRM positivity was an independent predictor of OS. More interestingly, the patterns of recurrence were different between the two groups, with R1-tumour leading to significantly more local recurrence (P = 0.04).

CONCLUSIONS

Our data strongly suggests that direct tumour involvement of the CRM confers worse prognosis after rectal cancer surgery. Importantly, differences in the site and frequency of recurrences make a case for better stratification of patients with a positive CRM to guide treatment decisions.

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.

The impact of subdivisions of microscopically positive (R1) margins on patterns of relapse in stage III colorectal cancer - A retrospective cohort study

AIM

Microscopically positive (R1) margins are associated with poorer outcomes in patients with colorectal cancer. However, the impact of subdivisions of R1 margins, be they to the primary tumour (R1 tumour) or to lymph node metastases (R1LNM), on patterns of relapse is unknown.

METHODS

Patients treated for stage III colorectal cancer from 01 January 2016 to 31 December 2019 in four specialist centres were identified from the Danish national cancer registry. Patients were stratified into three groups according to margin status (R0 vs. R1 tumour vs. R1LNM). The primary outcomes were local recurrence-free survival (LRFS), distant metastases-free survival (DMFS) and disease-specific survival (DSS).

RESULTS

A total of 1,164 patients were included, with R1 margins found in 237 (20.4%). Irrespective of tumour location, R1 tumour and R1LNM margins were independent prognostic factors for systemic relapse (R1 tumour HR 1.84, CI: 1.17-2.88, p = 0.008; R1LNM HR 1.59, CI: 1.12-2.27, p = 0.009) and disease-related death (R1 tumour HR 2.08, CI: 1.12-3.85, p = 0.020; R1LNM HR 1.84, CI: 1.12-3.02, p = 0.016). Whereas R1 tumour margins were associated with poorer 3-year LRFS in both colon and rectum cancer, R1LNM margins only reduced LRFS in patients with rectal cancer. Patterns of relapse differed between R1 subdivisions, with R1 tumour margins more likely to affect multiple anatomical sites, with a predilection for extra-hepatic/pulmonary metastases.

CONCLUSION

Subdivisions of R1 margins have a distinct impact on the oncological outcomes and patterns of disease relapse in patients with stage III colorectal cancer.

Feasibility of the semi-opened method of specimen resection for a circumferential resection margin in rectal cancer surgery: a multicenter study

PURPOSE

A circumferential resection margin (CRM) > 1 mm is a surrogate marker of oncologic outcomes in rectal cancer patients. In Japan, because the mesentery is removed from the rectum, the CRM cannot be measured. This multicenter prospective study evaluates the feasibility of a resected specimen processing method that allows CRM measurement.

METHODS

Fifty patients with rectal cancer were enrolled. Resected specimens were processed as previously reported. The primary outcomes were CRM measurement and the rate of CRM positivity. The secondary outcomes were the quality of total mesorectal excision, the possibility to visualize and sample the tumor, the number of harvested lymph nodes, and comparison between the pathological CRM and preoperative mesorectal fascia (MRF) involvement. This study was registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry under identification number UMIN000031735.

RESULTS

The CRM was measurable in all patients and found to be positive in three (6%). We confirmed tumor localization, sampled the tumor, and measured the distal margin in all patients. A median of 20 lymph nodes were harvested. The concordance rate between preoperative MRF involvement and pathological CRM status was 90%.

CONCLUSION

A semi-opened rectal specimen with transverse slicing is a feasible method for measuring the CRM.

Transanal total mesorectal excision for abdominoperineal resection is associated with poor oncological outcomes in rectal cancer patients: A word of caution from a multicentric Canadian cohort study

AIM

The main objective of this study was to compare the oncological outcomes of patients undergoing abdominoperineal resection (APR) versus low anterior resection (LAR) through a transanal total mesorectal excision (taTME) approach.

METHOD

A total of 360 adult patients with a diagnosis of rectal cancer were enrolled at participating centres from the Canadian taTME Expert Collaboration. Forty-three patients received taTME-APR and received 317 taTME-LAR. Demographic, operative, pathological and follow-up data were collected and merged into a single database. Results are presented as hazard ratio (HR) and 95% confidence interval. All analyses were performed in the R environment (v.3.6).

RESULTS

The proportion of patients with a positive circumferential radial margin status was higher in the taTME-APR group than the taTME-LAR group (21% vs. 9%, p = 0.001). Complete TME was achieved in 91% of those undergoing APR compared with 96% of those undergoing LAR (p = 0.25). APR was associated with a greater rate of local recurrence relative to LAR, although it was not significant [crude HR = 3.53 (95% CI 0.92-13.53)]. Circumferential margin positivity was significantly associated with a higher rate of systemic recurrence [crude HR = 3.59 (95% CI 1.38-9.3)].

CONCLUSION

Our results demonstrate inferior outcomes in those undergoing taTME-APR compared with taTME-LAR. The use of this technique for this particular indication needs to be carefully considered.

Structured and shared MRI staging lexicon and report of rectal cancer: A consensus proposal by the French Radiology Group (GRERCAR) and Surgical Group (GRECCAR) for rectal cancer

PURPOSE

To develop French guidelines by experts to standardize data acquisition, image interpretation, and reporting in rectal cancer staging with magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Evidence-based data and opinions of experts of GRERCAR (Groupe de REcherche en Radiologie sur le CAncer du Rectum [i.e., Rectal Cancer Imaging Research Group]) and GRECCAR (Groupe de REcherche en Chirurgie sur le CAncer du Rectum [i.e., Rectal Cancer Surgery Research Group]) were combined using the RAND-UCLA Appropriateness Method to attain consensus guidelines. Experts scoring of reporting template and protocol for data acquisition were collected; responses were analyzed and classified as "Recommended" versus "Not recommended" (when ≥ 80% consensus among experts) or uncertain (when < 80% consensus among experts).

RESULTS

Consensus regarding patient preparation, MRI sequences, staging and reporting was attained using the RAND-UCLA Appropriateness Method. A consensus was reached for each reporting template item among the experts. Tailored MRI protocol and standardized report were proposed.

CONCLUSION

These consensus recommendations should be used as a guide for rectal cancer staging with MRI.

The significance of subdivisions of microscopically positive (R1) margins in colorectal cancer: A retrospective study of a national cancer registry

AIM

Microscopically positive (R1) margins are associated with poorer outcomes in patients with colorectal cancer. However, little is known of the differential impact of subdivisions of R1 margins, be they to the primary tumour (R1tumour) or to lymph node metastases/tumour deposits (R1LNM).

METHODS

Patients treated for Stage III colorectal cancer from 1 January 2016 to 31 December 2019 were identified from the Danish national cancer registry. Patients were stratified into three groups according to margin status (R0 vs. R1tumour vs. R1LNM). The primary outcome was overall survival.

RESULTS

In all, 4186 patients were included, comprising 3012 patients with colon cancer and 1174 patients with rectal cancer. The R1 resection rates were 16.5% and 18.2% in patients with colon and rectum cancer, respectively. In colon cancers, 3-year overall survival was reduced in patients with R1LNM (65.7%, 95% CI 62.8-68.6) or R1tumour margins (51.8%, 95% CI 47.3-56.3) compared with R0 resections (80.8%, 95% CI 79.9-81.6, P < 0.001). A similar impact on survival was seen in rectal cancers (R0, 84.2%, 95% CI 82.9-85.5; R1LNM, 72.2%, 95% CI 67.8-76.6; R1tumour, 56.6%, 95% CI 50.0-63.2, P < 0.001). Margin status was independently prognostic of survival in both colon (R1tumour, hazard ratio 2.08, 95% CI 1.50-2.89, P < 0.001; R1LNM, hazard ratio 1.48, 95% CI 1.11-1.97, P = 0.008) and rectal cancers (R1tumour, hazard ratio 2.35, 95% CI 1.42-3.90, P < 0.001; R1LNM, hazard ratio 1.54, 95% CI 0.95-2.48, P = 0.077).

CONCLUSION

R1 subdivisions have distinct impacts on survival in Stage III colorectal cancer. Further focused research in these patient subgroups is warranted.

Robotic and robotic-assisted vs laparoscopic rectal cancer surgery: A meta-analysis of short-term and long-term results

The usage of robotic surgery in rectal cancer (RC) is increasing, but there is an ongoing debate as to whether it provides any benefit. This study conducted a meta-analysis of rectal cancer surgery for short-term and long-term outcome by Robotic and robotic-assisted surgery (RS) vs laparoscopic surgery (LS).Pubmed, Embase, Ovid, CNKI, Cochrane Library and Web of Science databases were searched. Studies clearly documenting a comparison of short-term and long-term effect between RS and LS for RC were selected. Lymph node harvested, operation time, hospital stay, circumferential resection margins（CRM), complications, 3-year disease-free survival (DFS) and 5-year DFS parameters were evaluated. All data were performed by Review Manager 5.3 software. Nine studies were collected that included 1436 cases in total, 716 (49.86%) in the RS group, 720(50.14%) in the LS group. Compared with LS, RS was associated with longer operation time (MD 35.19, 95%CI [7.57, 62.81]; P = 0.01), but similar hospital stay (MD -0.43, 95%CI [-0.87,0.01]; P = 0.05).Lymph node harvested, CRM, complications, 3-year DFS, 5-year DFS had no significance difference between RS and LS groups（MD -0.67，95%CI[-1.53，0.19]；P = 0.13；MD 0.86，95%CI[0.54,1.37]；P = 0.52；MD 0.97，95%CI [0.73,1.29]；P = 0.86；MD 0.94，95%CI[0.60,1.48]；P = 0.79；MD 0.88，95%CI[0.52,1.47]；P = 0.61 respectively）.RS is feasible and safe for RC. It has an advantage in short -term outcome and a similar effect in long-term outcome compared with LS.

What management for patients with R1 resection after total mesorectal excision for rectal cancer? A review of the literature

AIM OF THE STUDY

Treatment for rectal cancer is very standardized. However, for total mesorectal excision (TME) with positive margins at microscopic pathological examination (classified R1 ), there is no consensus regarding management. The objective of this update was, through a review of the literature, to identify the most suitable management to improve overall survival and/or recurrence-free survival after R1 TME for rectal cancer.

PATIENTS AND METHODS

Published national quality guidelines and original studies were searched on Pubmed. Only studies and recommendations concerning the specific management of patients who had undergone R1 TME resection were selected.

RESULTS

Five original non-randomized studies and seven published national quality guidelines were selected for review. For patients who have undergone R1 TME resection, the French and European published guidelines issued a Grade A recommendation in favor of post-operative radio-chemotherapy (RCT) for those in whom it had not already been performed pre-operatively. The French and European guidelines recommendation for adjuvant chemotherapy was based only on expert agreement. The original studies emphasized the survival benefit of adjuvant chemotherapy, as opposed to post-operative RCT, which did not seem to improve survival. Salvage surgery was not recommended in any of the studies.

CONCLUSION

After R1 TME resection for rectal cancer, adjuvant chemotherapy seems to be indicated when feasible, whereas post-operative RCT and salvage surgery do not appear to improve patient survival.

Dose-time fractionation schedules of preoperative radiotherapy and timing to surgery for rectal cancer

Chemoradiotherapy (CRT) is extensively used prior to surgery for rectal cancer to provide significantly better local control, but the radiotherapy (RT), as the other component of CRT, has been subject to less interest than the drug component in recent years. With considerable developments in RT, the use of advanced techniques, such as intensity-modulated radiotherapy (IMRT) in rectal cancer, is garnering more attention nowadays. The radiation dose can be better conformed to the target volumes with possibilities for synchronous integrated boost without increased complications in normal tissue. Hopefully, both local recurrence and toxicities can be further reduced. Although those seem to be of interest, many issues remain unresolved. There is no international consensus regarding the radiation schedule for preoperative RT for rectal cancer. Moreover, an enormous disparity exists regarding the RT delivery. With the advent of IMRT, variations will likely increase. Moreover, time to surgery is also quite variable, as it depends upon the indication for RT/CRT in the clinical practices. In this review, we discuss the options and problems related to both the dose-time fractionation schedule and time to surgery; furthermore, it addresses the research questions that need answering in the future.