Nonsurgical management of recurrent colorectal cancer.

Most patients with colorectal carcinoma undergo attempts at curative surgery. However, some present with metastatic disease and many others ultimately relapse. Most recurrences of colorectal cancer are not resectable and require nonsurgical approaches such as chemotherapy and radiation therapy directed against local recurrences, hepatic metastases, and widely disseminated disease. Nonsurgical therapy for locoregional recurrence of rectal cancer can offer significant palliation. Intraarterial chemotherapy for liver metastases increases the likelihood of response compared to systemic treatments, but has little effect on survival. Extrahepatic progression and hepatic toxicity are important limitations to this regional therapy. 5-fluorouracil (5-FU) is the mainstay of systemic chemotherapy, and efforts to modulate biochemically the cytotoxic effects of 5-FU with folinic acid, phosphonacetyl-L-aspartate, interferon, and other agents have resulted in promising response rates. The different approaches to biochemical modulation are being studied in ongoing cooperative group trials. Novel approaches, including monoclonal antibody therapy, biologic modifier therapy, and gene therapy, are under investigation.