Phase II Study of Pre-Operative Radiotherapy with Capecitabine and Oxaliplatin for Rectal Cancer and Carcinoembryonic Antigen as a Predictor of Pathological Tumour Response

Abstract

This study investigated the efficacy and tolerability of pre-operative radiotherapy with concurrent capecitabine and oxaliplatin in patients with rectal cancer. Forty-seven patients with rectal adenocarcinoma (stages T3 – T4; node-positive) were enrolled and received radiotherapy (46 Gy in 23 fractions) in combination with capecitabine (1000 mg/m² twice daily on days 1–14 and 22–35) and oxaliplatin (130 mg/m² on days 1 and 22) (XELOX regimen). The main endpoints were safety and efficacy, as assessed by pathological complete response (pCR). All patients received pre-operative chemoradiotherapy (CRT) as planned. The most common severe toxicity was diarrhoea (12.8%); post-operative complications were rare (9.8%). The pCR rate was 20.9% in all patients and 34.8% in patients with normal pre-CRT serum carcinoembryonic antigen (CEA < 5 ng/ml) level, compared with 5.0% in the patients with elevated CEA (> 5 ng/ml). In conclusion, pre-operative radiotherapy with concurrent XELOX regimen in rectal cancer patients is feasible and effective. Serum CEA may be a suitable predictor of pCR.