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

Abstract

IntroductionPatients 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. MethodsThe 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. ResultsAltogether, 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. ConclusionMost 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.