Sphincter-preserving surgery for low-middle rectal cancer: Can we predict feasibility with high-resolution magnetic resonance imaging?

Predicting the Feasibility of Curative Resection in Low Rectal Cancer: Insights from a Prospective Observational Study on Preoperative Magnetic Resonance Imaging Accuracy

Background and Objectives: A positive pathological circumferential resection margin is a key prognostic factor in rectal cancer surgery. The point of this prospective study was to see how well different MRI parameters could predict a positive pathological circumferential resection margin (pCRM) in people who had been diagnosed with rectal adenocarcinoma, either on their own or when used together. Materials and Methods: Between November 2019 and February 2023, a total of 112 patients were enrolled in this prospective study and followed up for a 36-month period. MRI predictors such as circumferential resection margin (mCRM), presence of extramural venous invasion (mrEMVI), tumor location, and the distance between the tumor and anal verge, taken individually or combined, were evaluated with univariate and sensitivity analyses. Survival estimates in relation to a pCRM status were also determined using Kaplan-Meier analysis. Results: When individually evaluated, the best MRI predictor for the detection of a pCRM in the postsurgical histopathological examination is mrEMVI, which achieved a sensitivity (Se) of 77.78%, a specificity (Sp) of 87.38%, a negative predictive value (NPV) of 97.83%, and an accuracy of 86.61%. Also, the best predictive performance was achieved by a model that comprised all MRI predictors (mCRM+ mrEMVI+ anterior location+ < 4 cm from the anal verge), with an Se of 66.67%, an Sp of 88.46%, an NPV of 96.84%, and an accuracy of 86.73%. The survival rates were significantly higher in the pCRM-negative group (p < 0.001). Conclusions: The use of selective individual imaging predictors or combined models could be useful for the prediction of positive pCRM and risk stratification for local recurrence or distant metastasis.

Postchemoradiation magnetic resonance imaging circumferential resection margin predicts treatment failure after multidisciplinary directed sphincter preservation in low rectal cancer

BACKGROUND

This study aimed to review the magnetic resonance imaging (MRI) features of patients with low rectal cancer (LRC) undergoing preoperative chemoradiotherapy (CRT) and investigate the risk factors for treatment failure after sphincter preserving surgery following preoperative CRT based on multidisciplinary approach.

OBJECTIVES

Patients who underwent standard CRT and sphincter preserving radical surgery for LRC between January 2000 and December 2011 were retrospectively reviewed. Sphincter preservation failure (SPF) was defined as any one of the following: positive pathologic circumferential resection margin, local recurrence, failure to repair ileostomy, or permanent stoma formation due to anastomotic complications.

RESULTS

Among the 191 patients, there were no overall significant differences between sphincter preservation success (n = 161) and SPF (n = 30) groups. SPF group showed a higher MRI circumferential resection margins (mrCRM) positive rate before and after CRT (before CRT: 33.3% vs. 16.1%, p = 0.027; after CRT: 23.3% vs. 6.2%, p = 0.002). Multivariate analysis showed that only mrCRM after CRT was associated with SPF (hazard ratio = 4.596, p = 0.005). SPF group showed worse 5-year cancer-specific survival (51% vs. 92.7%, p < 0.001).

CONCLUSIONS

MRI-based assessment of the tumor after CRT plays a crucial role in predicting the success and feasibility of sphincter preservation as well as oncological outcomes in patients with LRC.

Clinical application of laparoscopic total mesorectal excision using the intersphincteric approach through the sacrococcygeal incision for treating patients with rectal cancer

Introduction

Colorectal cancer is the third most common cancer causing death in Western countries; laparoscopic surgery for colorectal cancer has many advantages and thus has been used widely. Laparoscopic total mesorectal excision through the sacrococcygeal incision under direct visualization to excise distal rectal cancer is an important procedure for super-low rectal carcinomas.

Aim

To investigate the feasibility of mesorectal excision and super-low rectal carcinoma excision using the intersphincteric approach through the sacrococcygeal incision.

Material and methods

From December 2009 to June 2017, intersphincteric resection was performed through the sacrococcygeal incision; the mesentery was excised in 27 patients with rectal cancer and a contracted pelvis (the lower edge of the tumor was 4 to 7 cm to the anal verge) through laparoscopy in the Gastrointestinal Surgery Department of our hospital.

Results

No death was recorded during surgery. The surgical time ranged from 190 to 310 min, the bleeding volume was 50 to 150 ml, and the post-surgical length of stay was 6 to 19 days. There were three cases of anastomotic fistulas, one case of anastomotic stenosis, and one case of fecal incontinence. Follow-up visits were scheduled for 19 patients, with a mean time of 37 months, ranging from 3 to 92 months; one case of local recurrence, one case of peritoneal metastasis, and two cases of hepatic metastasis were observed.

Conclusions

Laparoscopic total mesorectal excision using the intersphincteric approach through the sacrococcygeal incision is feasible for treating patients with a contracted pelvis and super-low rectal carcinoma.