Adjuvant therapy for colon carcinoma: Current status and future directions

THE ADDITION of levamisole to 5-fluorouracil (5-FU) has been shown to improve overall survival in patients with resected lymph node-positive colon carcinoma, establishing this regimen as standard adjuvant therapy. Given that biochemical modulation of 5-FU by leucovorin has been shown to increase response rates in advanced disease, ongoing studies aim to evaluate this combination in the adjuvant setting. The possibility that levamisole and leucovorin may have additive effects is also under investigation. Further improvements in survival rates may be achieved through use of tumor vaccines, interferon-alpha, and new chemotherapeutic agents. Current efforts are also aimed at reducing the toxic effects of cancer chemotherapy. Advances in tumor biology may reveal new prognostic markers that may ultimately lead to more selective use of adjuvant cytotoxic therapy.