Phase II study of pre-operative radiotherapy with capecitabine and oxaliplatin for rectal cancer and carcinoembryonic antigen as a predictor of pathological tumour response.

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/m(2) twice daily on days 1 - 14 and 22 - 35) and oxaliplatin (130 mg/m(2) 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 < or = 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.