Physical weakness plays a major role in patients with advanced cancers. Nearly one-third of cancer deaths are believed to be attributed to a wasting syndrome called cachexia, characterized by a dramatic loss of skeletal muscle mass and weight. Doctors have also identified sarcopenia, or muscle mass loss usually associated with aging, as an important indicator of prognosis in advanced cancer patients. Typically, the less muscle mass an advanced cancer patient has, the lower his or her chance of surviving the disease. But new studies show early-stage cancer patients are also at risk, and doctors hope further research will show that building more muscle may help patients recover.
“ The goal is to alter the prognosis. Additional studies are needed to determine if increasing muscle mass in patients could improve outcomes.” - Cynthia Lynch, MD - Medical Director of the Breast Cancer Center and Medical Oncologist at our hospital in Phoenix
The most recent study, published in the April issue of JAMA Oncology, followed 3,241 stage II and stage III breast cancer patients, concluding that patients with low muscle mass at the time of diagnosis had a lower chance of survival than patients without sarcopenia. In the study, none of the patients’ cancers had yet spread beyond the breast at the time of diagnosis. The study’s authors concluded that even though sarcopenia occurs in more than one-third of newly diagnosed non-metastatic breast cancer patients, the condition has been under-recognized among that population.
The authors also said the findings may be applied to many other non-metastatic cancers, since the association between high muscle mass and improved survival for patients with metastatic disease has been observed in patients with a variety of solid tumors. A similar trial led by the study’s lead investigator, for example, linked low muscle mass in patients with non-metastatic colorectal cancer to a poor prognosis.
Sarcopenia combined with high body fat worsens patients’ outlooks even further. In the JAMA study, breast cancer patients who had both sarcopenia and high body fat were 89 percent more likely to die from the disease. The American Society of Clinical Oncology has also found that sarcopenia combined with inflammation nearly doubles patients’ risk of death from cancer.
Based on the findings, researchers are advising doctors to recommend strength training to patients with non-metastatic disease, in addition to weight loss and dietary changes. “I recommend exercise, as well as a healthy diet, as there are studies demonstrating the benefits of a healthy lifestyle in reducing the risk of breast cancer recurrence,” Dr. Lynch says. “I look forward to seeing studies performed that will evaluate the effects of improving muscle mass on breast cancer outcomes.”