Use of Chemotherapy After Surgery for Colon Cancer Has Risen

More patients with stage III colon cancer are receiving chemotherapy after surgery, with an associated significant increase in 5-year survival, according to a study in the December 7 issue of JAMA. The study also found that women, blacks and the elderly were less likely to receive this treatment.

According to background information in the article, based on the results of two trials, the National Institutes of Health Consensus Conference recommended in 1990 that adjuvant chemotherapy (chemotherapy after the primary tumor has been removed by some other method, as in surgery or radiation therapy) be given to all patients with stage III colon cancer who were not enrolled in a clinical trial. However, as with most recommendations, it is not clear to what extent they are followed or contribute to outcome in the general population.

J. Milburn Jessup, M.D., of the National Cancer Institute, Rockville, Md. and Georgetown University, Washington, D.C., and colleagues assessed to what extent the 1990 Consensus Conference recommendation has been followed in the community and whether adjuvant chemotherapy has improved the 5-year survival of patients with stage III colon cancer.

The study included data from 85,934 patients with stage III colon cancer from 560 hospital cancer registries who were entered into the National Cancer Data Base (NCDB) between 1990 and 2002. The data included standard clinical, pathological, and first course of treatment variables.

The researchers found an increase in the use of adjuvant chemotherapy for all patients with stage III colon cancers from 39 percent of patients in 1990 to 64 percent in 2002, but use was lower in black, female, and elderly patients. The difference in 5 year survival increased from an 8 percent improvement in the 1991 subgroup to 16 percent in the 1997 subgroup that received adjuvant chemotherapy compared with surgery alone. The researchers also found that adjuvant chemotherapy increases survival in elderly patients as much as it does in younger patients. However, the benefit of adjuvant chemotherapy in blacks and those with high-grade cancers is not as great.

"Future studies are needed to identify whether newer agents such as irinotecan and oxaliplatin may be more effective in patients with high-grade cancers or in blacks than the 5-fluorouracil and leucovorin regimens that were dominant during the time that the cohorts reported herein were followed up for survival," the authors conclude.

(JAMA.2005; 294:2703-2711. Available pre-embargo to the media at http://www.jamamedia.org)