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, according to a study by researchers from Pennington Biomedical Research Center.
"The conventional wisdom has been that colorectal cancer patients should avoid losing or gaining weight during treatment," said Dr Justin C Brown, Assistant Professor and Director of the Cancer Metabolism Program at Pennington Biomedical Research Center. "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."
The researchers added that 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," explained Dr John Kirwan, Executive Director.
The study, ‘Weight stability masks changes in body composition in colorectal cancer: a retrospective cohort 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.
At follow-up, 1026 (53.3%) patients were weight stable. Among patients with weight stability, incident sarcopenia and myosteatosis occurred in 8.5% (95% CI: 6.3%, 10.6%) and 13.5% (95% CI: 11.1%, 15.9%), respectively. Men were more likely to be weight stable than were women (56.7% compared with 49.9%; p=0.04). Weight-stable men were less likely to develop incident sarcopenia (5.4% compared with 15.4%; p=0.003) and myosteatosis (9.3% compared with 20.8%; p=0.001) than weight-stable women.
Among all patients, the development of incident sarcopenia (HR: 1.40; 95% CI: 1.02, 1.91) and of myosteatosis (HR: 1.41; 95% CI: 1.05, 1.90) were associated with a higher risk of death, independently of change in body weight. Patient sex did not modify the relation between skeletal muscle depletion and death.
"More research is needed to determine whether physical activity offers the best solution to prevent muscle loss or fatty deposits in muscle," added Brown. "But the findings provide colorectal cancer patients with more incentive to engage in physical activity programmes that maintain and build muscle.