Neoadjuvant treatment with capecitabine and oxaliplatin in combination with radiotherapy for rectal cancer patients: a phase II study

Background. Pre-operative chemoradiation is now standard treatment for stage II-III rectal cancer. Capecitabine (CAP) and oxaliplatin (OX) are synergistic with radiotherapy (RT) and active in colorectal neoplasms. Patients and Methods. Two cycles of CAP 825 mg/m2 bid (days 1-14) and OX 50 mg/m2 (days 1 & 8) every 3 weeks were given concomitantly with pelvic conformal RT (45 Gy). Patients with a ≥ T3 and/or node-positive rectal tumour were eligible. The pathologic tumour response was defined according to the Tumour Regression Grade (TRG) scale. Results. Forty-six patients were enrolled. Gastrointestinal adverse events were mostly G1-G2; only 2 patients experienced G3 vomiting and diarrhoea; 6 patients had G1 peripheral neuropathy. Haematological toxicity was rare. G2 proctitis and anal pain occurred in 2 patients. Pathological complete response (TRG1) was observed in 9 patients (20.9%; 95% CI 8.7-33.1%); TRG2 in 19 patients (44.2%); TRG3 in 12 patients (27.9%); TRG4 in 3 patients (7%). Overall, 9 patients recurred: 5 with distant metastases, 1 with local recurrence, and 3 with both local recurrence and distant metastases. Conclusions. CAP-OX-RT as pre-operative treatment for rectal cancer induces a remarkable rate of complete or near-complete pathological responses, and is well tolerated.