Commentary (Cohen): Radiation Therapy for Resectable Colon Cancer
February 02, 2006
Colon cancer is a major public health problem. The primary treatment is resection. For patients with early-stage disease, surgery results in excellent survival rates. In contrast, patients with locally advanced tumors arising in "anatomically immobile" segments of large bowel have a less satisfactory outcome, in part secondary to compromised surgical clearance. Patterns-of-failure analyses suggest that for tumors that invade adjacent organs, exhibit perforation or fistula, or are subtotally resected, local failure rates exceed 30%. Multiple single-institution retrospective studies have shown improved local control and possibly survival with the addition of external irradiation and/or intraoperative radiation. In contrast, a recent Intergroup trial failed to show any benefit by the addition of adjuvant radiation therapy combined with chemotherapy. Interpretation of this trial's results is handicapped by low patient accrual. With the advent of novel and more effective systemic therapies for metastatic colon cancer, current and future clinical research will address the efficacy of these agents in the adjuvant setting. Adjuvant radiation therapy should be considered in patients with colon cancer at high risk for local failure.