Adjuvant treatment in colorectal cancer: An update

Abstract

Analysisof current and recently completed trials of adjuvant therapy for colorectal cancer permit a few very broad generalizations. Survival of patients initially treated by resection has improved during the past 2 decades, unrelated to adjuvant therapy. While pilot, uncontrolled, and historically controlled studies often suggest a treatment benefit, controlled trials have, to date, failed to show any advantage for adjuvant therapy in colon cancer. For rectal cancer, only those trials including radiation therapy alone or in combination with chemotherapy have provided enhanced patient survival. Superiority of preoperative versus postoperative radiotherapy has not been demonstrated. Of interest is the current United States intergroup trial in colon cancer which is evaluating ievamisole in combination with 5-fluorouracil, based on preliminary experience in a smaller study of the North Central Cancer Treatment Group which suggests that levamisole and 5-fluorouracil may be a potentially beneficial adjuvant combination. Recent reports of pharmacologic modulation of 5-fluorouracil resulting in significantly enhanced response rates in advanced metastatic colorectal cancer invite a trial of this pharmacologic concept for surgical adjuvant therapy.