Among women with nonmetastatic breast cancer, low muscle mass and excess body fat are significantly associated with worse survival, investigators report.
An observational study of 3,241 women diagnosed with stage II or III breast cancer showed that low muscle mass (sarcopenia) was independently associated with a 41% increase in risk for overall mortality, and that total adipose tissue (TAT) measures were associated with a 35% increase in overall mortality.
Women with sarcopenia and high total TAT scores had a nearly twofold higher risk for death, reported Bette J. Caan, DrPH, of Kaiser Permanente in Oakland, Calif., and her colleagues.
Although low muscle mass was found to be a significant risk factor for death, neither poor muscle quality, measured by radiodensity, nor body mass index (BMI) were significantly associated with overall mortality, the investigators reported in a study published online in JAMA Oncology.
“Both muscle and adiposity represent modifiable risk factors in patients with breast cancer. In addition to weight loss, we should also consider interventions to improve muscle mass, such as resistance training or protein supplementation. In the era of precision medicine, the direct measurement of muscle and adiposity will help to guide treatment plans and interventions to optimize survival outcomes,” they wrote.
Although moderate to severe obesity measured by high BMI has been associated with worse outcomes for patients with breast cancer and other malignancies, the evidence is mixed for those who are merely overweight or have borderline obesity, the authors noted.