Complete response of lung metastases from rectal cancer to combination first-line therapy of S-1 and irinotecan plus bevacizumab: A case report and review of the literature

This report presents the case of a 72-year-old male who had undergone abdominoperineal resection following a diagnosis of lower rectal cancer with multiple lung metastases. Pathologically, the resected specimen exhibited advanced rectal cancer with regional lymphoid metastases and was classified as stage IV disease. S-1 and irinotecan (IRIS) plus bevacizumab combination therapy was used to treat the lung metastases following the surgery. S-1 (100 mg/body) was administered orally on days 1-14 of a 28-day cycle, and irinotecan (125 mg/m2) and bevacizumab (7.5 mg/kg) were administered by intravenous infusion on days 1 and 15. Computed tomography revealed a marked decrease in the size of the metastases following three therapeutic courses, and no lung metastases or new lesions were detected following nine therapeutic courses. The response was declared clinically complete. The patient refused additional treatment following nine therapeutic courses, and there was no recurrence 36 months after the final course of therapy. This case demonstrates the efficacy of IRIS plus bevacizumab as a first-line combination therapy against lung metastases of rectal cancer.