Outcomes of rectal cancer patients with a positive pathological circumferential resection margin

Evidence-based management of positive pathological circumferential resection margin (pCRM) following preoperative radiation and an adequate rectal resection for rectal cancers is lacking.

Retrospective analysis of prospectively maintained single-centre institutional database was done to study the patterns of failure and management strategies after a rectal cancer surgery with a positive pCRM.

A total of 86 patients with rectal adenocarcinoma with a positive pCRM were identified over 8 years (2011-2018). Majority had low-lying rectal cancers (90.7%) and were operated after preoperative radiotherapy (95.3%). Operative procedures included abdomino-perineal resections, inter-sphincteric resections, low anterior resections and pelvic exenteration in 61 (70.9%), 9 (10.5%), 11(12.8%) and 5 (5.8%) patients respectively. A total of 83 (96.5%) received chemotherapy as the sole adjuvant treatment modality while 2 patients (2.3%) were given post-operative radiotherapy and 1 patient underwent revision surgery. A total of 53 patients (61.6%) had recurrence, with 16 (18.6%), 20 (23.2%), 8(9.3%) and 9 (10.5%) patients having locoregional, systemic, peritoneal and simultaneous local-systemic relapse. Systemic recurrences were more often detected either by surveillance in an asymptomatic patient (20.1%) while local (13.1%) and peritoneal (13.2%) recurrences were more often symptomatic (p = 0.000). The 2-year overall survival (OS) and disease-free survival (DFS) of the cohort was 82.4% and 74.0%. Median local recurrence-free survival (LRFS) was 10.3 months.

Patients with a positive pCRM have high local and distal relapse rates. Systemic relapses are more often asymptomatic as compared to peritoneal or locoregional relapse and detected on follow-up surveillance. Hence, identification of such recurrences while still salvageable via an intensive surveillance protocol is desirable.