Adjuvant Management of Pathologic Node-Positive Disease After Definitive Surgery for Clinical T1-2 N0 Rectal Cancer.

INTRODUCTION: Patients with cT1-2N0M0 rectal cancer are often treated with up-front surgical resection, with adjuvant treatment reserved for patients upstaged with pathologic node-positive (pN+) disease at surgery. This study evaluates practice patterns and clinical outcomes when comparing different forms of adjuvant treatment for this patient population.

METHODS: The National Cancer Data Base was queried for cT1-2N0M0 rectal cancer patients between 2004 and 2015 with postoperative pN+ disease treated without neoadjuvant treatment. Patients were divided into groups receiving observation, chemotherapy, or chemoradiotherapy (CRT). Multivariable logistic regression determined factors associated with receipt of adjuvant treatment. Kaplan-Meier curves compared overall survival (OS), and Cox regression determined patient factors associated with OS.

RESULTS: Altogether, 1466 patients met the inclusion criteria; 536 patients (36.6%) received adjuvant chemotherapy, 413 (28.2%) received adjuvant CRT, and 517 (35.3%) were observed postoperatively. Use of adjuvant treatment was associated with superior median OS (124.1 vs. 51.1 months, P < .001), persisting after propensity score matching (124.0 vs. 61.9 months, P < .001), but not between adjuvant CRT versus chemotherapy on subset analysis. Patients with positive surgical margins receiving adjuvant CRT showed a trend toward OS improvement compared to patients managed with chemotherapy (54.9 vs. 47.4 months, P = .10). Increased age, pN2 status, positive margin status, and observation were associated with poorer OS.

CONCLUSION: Most patients found to have pN+ disease after up-front surgery for cT1-2N0 rectal cancer receive adjuvant treatment, which is associated with improved OS. Chemotherapy or CRT are appropriate options, although there was a trend toward higher OS for patients with positive surgical margins receiving CRT.