Breast cancer patients who have high muscle mass have a greater chance of surviving the disease than those who have lower muscle mass, according to a new study published in the journal JAMA Oncology.
Researchers from Kaiser Permanente, the University of Alberta and the Dana Farber Cancer Institute looked at CT scans of the abdominal area of 3,241 women with stage 2 or 3 invasive breast cancer to determine if they had sarcopenia (muscle loss), poor muscle quality or adiposity (excess fat). The researchers then compared the mortality rates among the group. One-third (34 percent) of the patients had muscle loss and a mortality rate of 41 percent. Patients with the highest levels of excess fat had a mortality rate of 35 percent. Those with both muscle loss and excess fat were most at risk of dying; they had a mortality rate of 89 percent.
Researchers noted that the connection between body size and cancer survival has been of “great clinical interest” and often studied. Body mass index has been the primary tool to evaluate body size and to measure a patient’s chances of survival. BMI, however, doesn’t take into account the body's composition of fat and muscle, which abdominal CT scans are able to determine. In what they are calling the largest study to date of patients with nonmetastatic (non-spreading) breast cancer, researchers assert that CT scans outperform BMI measurement in the ability to provide “significant prognostic information.”
The women ranged in age from 18 to 80 (the median age was 54). The researchers found that survival due to higher muscle mass was consistent across age, BMI and cancer stage. The study results add to other information about the role that muscle may play in health outcomes. Previous research has shown strength training can help with diabetes, heart disease, osteoporosis and other illnesses.