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

PURPOSE: To evaluate the efficacy and safety of preoperative chemoradiation with cetuximab, irinotecan, and capecitabine in patients with rectal cancer.

METHODS AND MATERIALS: 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.

RESULTS: 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.

CONCLUSIONS: 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.