Clinical trials of new treatments are also appropriate.
More than half the patients with colon cancer have tumors that penetrate the serosa (B2) or have positive lymph nodes (C). It is estimated that about 20 to 25 percent of those with Dukes' B2 and 40 to 90 percent of those with Dukes' C who are treated with surgery will have recurrences and so need adjuvant chemotherapy .
Dukes' C patients now commonly receive a combination of levamisole + 5-FU (which was recommended by the U.S. National Institutes of Health's Consensus Conference on Colon Cancer in May 1990). One study of treatment with levamisole + 5-FU for Dukes' C starting within five weeks of surgery did show decreased recurrences and prolonged survival. Another trial showed a 41 percent decrease in the rate of recurrence and a 33 percent decrease in the death rate.
