A pilot randomized study comparing extralevator versus conventional abdominoperineal excision for low rectal cancer after neoadjuvant chemoradiation

Aims: The aims of this study were to assess the feasibility of performing an extralevator abdominoperineal excision (ELAPE) after neoadjuvant chemoradiation, to compare the rates of circumferential resection margin (CRM) involvement and intra-operative perforation (IOP) of the specimen, and to assess the amount of tissue removed around the muscularis propria (MP)/internal sphincter (IS) of the lower rectum in patients with low rectal cancer undergoing ELAPE as compared to conventional abdominoperineal excision (CAPE) after NCRT. Methods: This was an open-label, parallel arm pilot randomized trial conducted in India. Twenty patients were randomised to one of the study arms. The surgical specimens were fixed, serially cross-sectioned and photographed. Using specialised morphometry software, the amount of tissue resected with each operation was measured. Results: There was a non-significant trend towards more intra-operative perforations (30% vs 0%, p=0.06) and a higher CRM involvement rate (40% vs 20%, p=0.32) in the CAPE arm. ELAPE removed a significantly greater amount of tissue around the IS/MP when compared to CAPE (1911.39 ± 382mm² vs 1132.03 ± 371mm²[SD], p<0.001). The mean distance from the IS/MP to the CRM was significantly greater in the ELAPE arm both in the posterior (28.28 ± 3mm vs 9.63 ± 3mm[SD], p<0.001) and lateral (13.69 ± 3mm vs 9.72 ± 3mm[SD], p=0.009) parts of the rectum but not in the anterior part (6.74 ± 2mm vs 6.10 ± 4mm [SD], p=0.64). The short-term morbidity was not significantly different between the two procedures. Conclusion: ELAPE removed more tissue in the lower rectum and resulted in a lower rate of IOP and CRM involvement when compared with CAPE even after NCRT.