Preoperative chemoradiation with cetuximab, irinotecan, and capecitabine in patients with locally advanced resectable rectal cancer: a multicenter Phase II study.

To evaluate the efficacy and safety of preoperative chemoradiation with cetuximab, irinotecan, and capecitabine in patients with rectal cancer. Forty patients with locally advanced, nonmetastatic, and mid- to lower rectal cancer were enrolled. Radiotherapy was delivered at a dose of 50.4 Gy/28 fractions. Concurrent chemotherapy consisted of an initial dose of cetuximab of 400 mg/m(2) 1 week before radiotherapy, and then cetuximab 250 mg/m(2)/week, irinotecan 40 mg/m(2)/week for 5 consecutive weeks and capecitabine 1,650 mg/m(2)/day for 5 days a week (weekdays only) from the first day during radiotherapy. Total mesorectal excision was performed within 6 ± 2 weeks. The pathologic responses and survival outcomes were evaluated as study endpoints, and an additional KRAS mutation analysis was performed. In total, 39 patients completed their planned preoperative chemoradiation and underwent R0 resection. The pathologic complete response rate was 23.1% (9/39), and 3 patients (7.7%) showed near total regression of tumor. The 3-year disease-free and overall survival rates were 80.0% and 94.7%, respectively. Grade 3/4 toxicities included leukopenia (4, 10.3%), neutropenia (2, 5.1%), anemia (1, 2.6%), diarrhea (2, 5.1%), fatigue (1, 2.6%), skin rash (1, 2.6%), and ileus (1, 2.6%). KRAS mutations were found in 5 (13.2%) of 38 patients who had available tissue for testing. Clinical outcomes were not significantly correlated with KRAS mutation status. Preoperative chemoradiation with cetuximab, irinotecan, and capecitabine was active and well tolerated. KRAS mutation status was not a predictive factor for pathologic response in this study.