Oxaliplatin-containing adjuvant chemotherapy improves the survival of locally advanced rectal cancer patients with pathological complete response after pre-operative chemoradiotherapy

BACKGROUND: The necessity for adjuvant chemotherapy (ACT) in locally advanced rectal cancer (LARC) patients who achieve pathological complete response (pCR) after pre-operative chemoradiotherapy (CRT) is still not identified. We aimed to investigate the therapeutic value of ACT in these patients. METHODS: Clinical data were retrospectively collected from 105 consecutive LARC patients who achieved pCR after pre-operative CRT and underwent radical tumor resection between December 2008 and April 2014 in a comprehensive cancer center. Perioperative chemotherapy (CT) was administered by combining oxaliplatin with capecitabine (XELOX regimen). Disease-free survival (DFS) and overall survival (OS) rates of patients with or without ACT were compared. RESULTS: Eighty-three (79.0%) patients received ACT and 22 (21.0%) did not. With a median follow-up of 49 months, the ACT group had a significantly higher 3-year DFS rate (92.8 vs 86.4%, p = 0.029) and 3-year OS rate (95.1 vs 86.1%, p = 0.026) than the non-ACT group. In multivariable analyses, the presence of ACT was an independent prognostic factor for DFS (hazard ratio [HR]: 0.271; 95% confidence interval (CI): 0.080–0.916; p = 0.036) but not for OS. This benefit was more obvious in patients younger than 60 years via subgroup analysis (adjusted HR: 0.106; 95% CI: 0.019–0.606; p = 0.012). CONCLUSIONS: Oxaliplatin-containing ACT may confer survival benefits to patients with pCR, particularly younger patients. However, the routine use of ACT in patients with pCR needs further validation.