Local excision and adjuvant radiation versus radical surgery for early-stage low-risk rectal cancer

Total mesorectal excision for early-stage rectal adenocarcinoma provides maximal oncologic control but is associated with impaired quality of life. Local excision with adjuvant chemoradiotherapy may be an acceptable alternative approach while minimizing morbidity. This study compares overall survival of patients with low-risk pT2N0/x rectal adenocarcinoma treated with total mesorectal excision and those treated with local excision and adjuvant chemoradiotherapy. We hypothesized that there would be not be a statistically significant difference in overall survival between these two groups.

The National Cancer Database (2004-2020) was queried for patients with cT1N0 and cT2N0 rectal adenocarcinoma who underwent surgery and had pT2N0 or pT2Nx tumors. Patients with tumors that lacked high-risk features were included in a low-risk cohort. Patients were classified by treatment: total mesorectal excision, local excision with adjuvant chemoradiotherapy, or local excision only. The primary outcome of overall survival was compared using Kaplan-Meier survival analysis and Cox proportional hazard regression.

8484 patients were included. 6815 (80.3%) underwent total mesorectal excision, 685 (8.1%) local excision with adjuvant chemoradiotherapy, and 984 (11.6%) local excision alone. Median follow-up was 62.1 months. Among patients with low-risk cancer (47.4%), overall survival was similar between total mesorectal excision and local excision with adjuvant chemoradiotherapy (HR 1.25, 95% CI 0.91-1.72).

In patients with low-risk pT2N0/x rectal adenocarcinoma, a statistically significant difference in overall survival was not observed between treatment with total mesorectal excision and local excision with adjuvant chemoradiotherapy. This finding supports the conduction of prospective trials to futher evaluate this research question.