In women with colon cancer that has advanced beyond the early stage, obesity is associated with a poorer long-term outcome, researchers report in the August 1st issue of the journal Cancer.

"In addition to an increased risk of developing colon cancer, obese patients may have an increased risk of cancer recurrence, at least women," Dr. Jeffrey A. Meyerhardt from Dana-Farber Cancer Institute in Boston told Reuters Health.

However, the influence of body weight on long-term outcomes and treatment-related side effects in colon cancer patients has not been well documented. Dr. Meyerhardt's group conducted a study of 3,759 patients with high-risk, stage II and III colon cancer who where participating in a chemotherapy trial.

They followed 3,438 subjects for about of 9.4 years and determined outcomes for all weight ranges.

The researchers found that women, but not men, who were overweight at the start of the trial had a significant increase in overall risk of death compared with women of normal weight. Obese women were also more likely to experience cancer recurrence.

Body weight had no significant influence on overall risk of death or cancer recurrence in men.

Dr. Meyerhardt said his group, led by Dr. Charles S. Fuchs of Dana-Farber Cancer Institute, is currently involved in a study to look at whether weight loss can improve outcomes patients who undergo surgery for colon cancer.

It is noteworthy, the investigators say, that obese patients did not experience a higher rate of chemotherapy-related toxic side effects. On the contrary, they had lower rates of decreases in white blood cells and lower rates of any very serious toxicities compared with their normal-weight counterparts.

"Obese patients tolerate chemotherapy as well as non-obese patients and should be treated aggressively based on their actual body weight," Dr. Meyerhardt told Reuters Health.