Triweekly XELOX Versus Single Capecitabine Concomitant with Neoadjuvant Radiotherapy for Locally Advanced Rectal Cancer

Abstract

To compare the long-term survival outcomes, acute toxicities and surgical complications between locoregionally advanced rectal cancer (LARC) patients who received either triweekly XELOX or single Capecitabine during concurrent chemoradiotherapy. Between September 2007 and July 2017, patients with stage II-III rectal cancer treated with neoadjuvant chemotherapy using either triweekly XELOX (Oxaliplatin 130mg/m2 plus capecitabine 825mg/m2) or capecitabine followed by definitive surgery were included. In an intent to-treat analysis, patients were assigned to the triweekly XELOX or capecitabine group according to the concurrent chemotherapy regimens. Variables potentially influencing treatment outcomes including age, sex, stage, adjuvant chemotherapy, interval from radiotherapy to surgery and radiation technology were used to generate propensity scores (PS) for the use of triweekly XELOX. We compared overall survival (OS), distant metastasis-free survival (DMFS), locoregional relapse-free survival (LRFS), and disease-free survival (DFS) by treatment group using Kaplan–Meier analysis, adjusting for PS. We then determined the risk of toxicities and surgical complications using PS-adjusted logistic regression. Multivariate Cox proportional hazard regression was used to analyze the major factors affecting survival. A total of 801 LARC patients were included in the analysis; 274 (34.2%) patients received triweekly XELOX and 527 (65.8%) received capecitabine alone. The median follow-up was 53 months (range, 6-140 months). The 5-year OS, DMFS, LRFS and DFS were 81.5% vs. 84.4% (P = 0.360), 79.5% vs. 83.1% (P = 0.241, 96.9% vs. 96.7% (P = 0.872), and 71.7% vs. 77.4% (P = 0.183) for the groups treated with triweekly XELOX and capecitabine, respectively. After PS adjustment, also no statistically significant survival differences were found between the two treatment groups. Adjusting for PS, the similar incidences of acute toxicities and surgical complications were observed between the two groups. Pathological complete response was the only significant predictor for OS, DMFS, and DFS, but not for the LRFS, in both unadjusted cohort and PS-adjusted cohort. Triweekly XELOX or capecitabine concurrently with neoadjuvant radiotherapy leads to similar acute toxicities, surgical complications and long-term survival outcomes in LARC patients.