Colorectal cancer survivors who maintained a stable body weight but lost muscle and developed fatty deposits in their muscles faced a 40 percent higher risk of premature death than patients who avoided both health issues.

The conventional wisdom has been that colorectal cancer patients should avoid losing or gaining weight during treatment. But maintaining your weight does not mean your body composition remains the same. Muscle can change quite dramatically, and those changes are associated with a much higher risk of death."

Dr. Justin C. Brown, Assistant Professor and Director of Cancer Metabolism Program, Pennington Biomedical Research Center

The researchers say assessing body composition by computed tomography images may be a vital method of identifying patients at increased risk of death.

This study highlights how body composition can have a powerful impact on long-term health. We at Pennington Biomedical are committed to conducting innovative research to enable cancer survivors around the world to achieve their best possible health," said Dr. John Kirwan, Executive Director.

The study, published in The American Journal of Clinical Nutrition, looked at 1,921 patients with stage I-III colorectal cancer. Skeletal muscle and body weight were measured at diagnosis and an average of 15 months later. Stable body weight was defined as being within plus or minus 5 percent of weight at diagnosis.

Researchers found that stable body weight masks clinically meaningful skeletal muscle depletion. Women were particularly vulnerable to losing muscle. One in five women with stable body weight lost muscle, while less than one in 10 men did.

"More research is needed to determine whether physical activity offers the best solution to prevent muscle loss or fatty deposits in muscle," Dr. Brown said. "But the findings provide colorectal cancer patients with more incentive to engage in physical activity programs that maintain and build muscle."