Neo-adjuvant treatment of rectal cancer with capecitabine and oxaliplatin in combination with radiotherapy: a phase II study

Background: Preoperative chemoradiation is now standard treatment for stages 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/m(2) b.i.d. (days 1-14) and OX 50 mg/m(2) (days 1 and 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 two patients experienced G3 vomiting and diarrhoea and six patients had G1 peripheral neuropathy. Haematological toxicity was rare. G2 proctitis and anal pain occurred in two patients. Pathological complete response (TRG1) was observed in nine patients (20.9%; 95% CI 8.7%-33.1%); TRG2 in 19 patients (44.2%); TRG3 in 12 patients (27.9%); and TRG4 in three patients (7%). Overall, nine patients recurred: five with distant metastases, one with local recurrence, and three with both local recurrence and distant metastases. Conclusions: CAP-OX-RT as preoperative treatment for rectal cancer induces a remarkable rate of complete or near-complete pathologically documented response and is well tolerated.