The Efficacy of Adjuvant Chemotherapy in Patients with Stage II/III Resected Rectal Cancer Treated with Neoadjuvant Chemoradiation Therapy

Introduction: Patients with stage II/III rectal cancers are treated with neoadjuvant chemoradiation and surgical resection followed by adjuvant chemotherapy (CT) per practice guidelines. It is unclear whether adjuvant CT provides survival benefit, and the purpose of this study was to measure outcomes in patients who did and did not receive adjuvant CT. Materials and Methods: We used a prospectively collected database for patients treated at The Ohio State University, and analyzed overall survival (OS), time to recurrence, patient characteristics, tumor features, and treatments. Survival curves were estimated using Kaplan-Meier method and compared by the log-rank test. Age was compared using the Wilcoxon test, and other categorical variables were compared using the χ 2 or Fisher exact test. Results: Between August 2005 and July 2011, 110 patients were identified and 71 patients had received adjuvant CT. There was no significant difference in sex, race, pathologic tumor stage, and pathologic complete response between the 2 patient groups. Although patient characteristics showed a difference in age (median age 54.3 vs. 62 y, P=0.01) and advanced pathologic nodal status (43% vs. 19%, P=0.02), there was a significant difference in OS. Median OS was 72.6 months with CT versus 36.4 months without CT (P=0.0003). Median time to recurrence has not yet been reached. Conclusions: In this retrospective analysis, adjuvant CT was associated with a longer OS despite more advanced pathologic nodal staging. Prospective randomized studies are warranted to determine whether adjuvant CT provides a survival benefit for patients across the spectrum of stage II and III rectal cancer.