Impact of a multidisciplinary training programme on outcome of upper rectal cancer by critical appraisal of the extent of mesorectal excision with postoperative MRI

Tumour-specific mesorectal excision for rectal cancer: Systematic review and meta-analysis of oncological and functional outcomes

BACKGROUND

Tumour-specific mesorectal excision (TSME) practice for rectal cancer only relies on small retrospective studies. This study aimed to perform a systematic review and meta-analysis to assess the oncological and functional outcomes of TSME practice.

METHODS

A systematic review protocol was drawn to include all the studies that compared partial versus total mesorectal excision (PME vs TME) practised for rectal adenocarcinoma up to 16 cm from the anal verge. A systematic literature search was conducted on EMBASE-Medline, Pubmed and Cochrane Library. Reports were screened for the study's outcomes: oncological radicality, postoperative anastomotic leak risk and functional outcomes. Included studies were appraised for risk-of-bias and meta-analysed. Evidence was rated with the GRADE approach.

RESULTS

Twenty-seven studies were included, consisting of 12325 patients (PME n = 4460, 36.2%; TME n = 7865, 63.8%). PME was performed for tumours higher than 10 cm from the anal verge in 54.5% of patients. There was no difference between PME and TME in circumferential resection margin positivity (OR 1.31, 95%CI 0.43-3.95, p = 0.64; I2 = 38%), and local recurrence risk (HR 1.05, 95%CI 0.52-2.10, p = 0.90; I2 = 40%). The postoperative leak risk (OR 0.42, 95%CI 0.27-0.67, p < 0.001; I2 = 60%) and the major low anterior resection syndrome risk (OR 0.34, 95%CI 0.28-0.40, p < 0.001; I2 = 0%) were lower after PME surgery. No difference was found in urinary incontinence (OR 0.68, 95%CI 0.13-3.67, p = 0.66) and urinary retention after early catheter removal (OR 2.00, 95%CI 0.24-16.51, p = 0.52).

CONCLUSIONS

Evidence from this meta-analysis shows that TSME for rectal cancer has good oncological results and leads to the best-fitted functional results possible for the patient's condition.

Required distal mesorectal resection margin in partial mesorectal excision: a systematic review on distal mesorectal spread

BACKGROUND

The required distal margin in partial mesorectal excision (PME) is controversial. The aim of this systematic review was to determine incidence and distance of distal mesorectal spread (DMS).

METHODS

A systematic search was performed using PubMed, Embase and Google Scholar databases. Articles eligible for inclusion were studies reporting on the presence of distal mesorectal spread in patients with rectal cancer who underwent radical resection.

RESULTS

Out of 2493 articles, 22 studies with a total of 1921 patients were included, of whom 340 underwent long-course neoadjuvant chemoradiotherapy (CRT). DMS was reported in 207 of 1921 (10.8%) specimens (1.2% in CRT group and 12.8% in non-CRT group), with specified distance of DMS relative to the tumor in 84 (40.6%) of the cases. Mean and median DMS were 20.2 and 20.0 mm, respectively. Distal margins of 40 mm and 30 mm would result in 10% and 32% residual tumor, respectively, which translates into 1% and 4% overall residual cancer risk given 11% incidence of DMS. The maximum reported DMS was 50 mm in 1 of 84 cases. In subgroup analysis, for T3, the mean DMS was 18.8 mm (range 8-40 mm) and 27.2 mm (range 10-40 mm) for T4 rectal cancer.

CONCLUSIONS

DMS occurred in 11% of cases, with a maximum of 50 mm in less than 1% of the DMS cases. For PME, substantial overtreatment is present if a distal margin of 5 cm is routinely utilized. Prospective studies evaluating more limited margins based on high-quality preoperative magnetic resonance imaging and pathological assessment are required.

Postoperative MRI Findings Following Conventional and Extralevator Abdominoperineal Excision in Low Rectal Cancer

Aim: The disparity in outcomes for low rectal cancer may reflect differences in operative approach and quality. The extralevator abdominoperineal excision (ELAPE) was developed to reduce margin involvement in low rectal cancers by widening the excision of the conventional abdominoperineal excision (c-APE) to include the posterior pelvic diaphragm. This study aimed to determine the prevalence and localization of inadvertent residual pelvic diaphragm on postoperative MRI after intended ELAPE and c-APE. Methods: A total of 147 patients treated with c-APE or ELAPE for rectal cancer were included. Postoperative MRI was performed on 51% of the cohort (n = 75) and evaluated with regard to the residual pelvic diaphragm by a radiologist trained in pelvic MRI. Patient records, histopathological reports, and standardized photographs were assessed. Pathology and MRI findings were evaluated independently in a blinded fashion. Additionally, preoperative MRIs were evaluated for possible risk factors for margin involvement. Results: Magnetic resonance imaging-detected residual pelvic diaphragm was identified in 45 (75.4%) of 61 patients who underwent ELAPE and in 14 (100%) of 14 patients who underwent c-APE. An increased risk of margin involvement was observed in anteriorly oriented tumors with 16 (22%) of 73 anteriorly oriented tumors presenting with margin involvement vs. 7 (9%) of 74 non-anteriorly oriented tumors (p = 0.038). Conclusion: Residual pelvic diaphragm following abdominoperineal excision can be depicted by postoperative MRI. Inadvertent residual pelvic diaphragm (RPD) was commonly found in the series of patients treated with the ELAPE technique. Anterior tumor orientation was a risk factor for circumferential resection margin (CRM) involvement regardless of surgical approach.