Phase II study of preoperative radiotherapy and concomitant weekly intravenous oxaliplatin combined with oral capecitabine for stages II-III rectal cancer.

INTRODUCTION: A prospective phase II study was conducted to assess the clinical activity and tolerability of oxaliplatin, capecitabine, and radiotherapy (RT) for neoadjuvant therapy of stages II-III rectal cancer. MATERIALS AND METHODS: Patients with histologically confirmed stages II-III (T3-T4 and/or N+) resectable rectal adenocarcinoma were eligible. Capecitabine was administered at 825 mg/m(2) twice daily for 5 days/week and oxaliplatin at 50 mg/m(2) on day 1 weekly for 5 weeks starting the first day of RT (before RT). RT consisted of a total dose of 45 Gy delivered in 25 fractions of 1.8 Gy, 5 days per week, for 5 weeks. RESULTS: A total of 46 patients were included (35 male, 10 female, median age 62 years). TNM Stage was T3 in 43 patients and T4 in 2. Twenty-eight patients had suspected nodal involvement. The intended chemoradiation treatment was completed in 94 % patients. Grade 3/4 toxicity included lymphocytopenia (6 patients), diarrhea (4 patients), emesis (2 patients), asthenia (3 patients), anorexia (1 patient), and hepatic toxicity (1 patient). Grade 1 neurotoxicity occurred in 18 patients, Grade 2 neurotoxicity in 3, and Grade 1 palmoplantar erythrodysesthesia in 2. Forty-two patients underwent surgery (complete resection 95 %, sphincter-saving operation 55 %). The overall pathologic response rate was 83 %, with a pathologic complete response (pCR) rate of 11.9 % (95 % CI 4.0-25.6). CONCLUSIONS: The pCR rate observed with oxaliplatin plus capecitabine and RT did not reach the pre-specified criteria of efficacy in this trial, which is in line with recent results of randomized phase III trials.