Chemotherapy of large intestinal carcinoma. Current results and future prospects.

Chemotherapy of advanced stages of large bowel cancer has until recently made little progress since the introduction of 5-FU 16 years ago. While survival is improved for patients who respond, 5-FU alone has made little impact on life span of the overall population of patients. Mitomycin-C and the chloroethyl nitrosourea antitumor agents, and in particular methyl-CCNU, have also demonstrated marginal activity in large bowel cancer. Two recently reported controlled clinical trials of combination chemotherapy have demonstrated response rates that are substantially better than those obtained with 5-FU alone; a 43% response rate in colorectal carcinoma has been reported using a combination of 5-FU, BCNU, vincristine, and DTIC, compared to a 25% response with 5-FU as a single agent; a 44% objective response rate with a combination of 5-FU, methyl-CCNU, and vincristine has been reported to be significantly better than 5-FU alone. 5-FU as an adjuvant following surgical resection with curative intent has not prevented tumor relapse; however, it is hoped that future studies employing more effective drug combinations will result in increased number of patients achieving disease free survival.