A new study shows that post-diagnosis weight gain can increase the risk of death from breast cancer, although researchers did not narrow the effects based on receptor status. Women who gained more than 22 pounds after diagnosis were 83 percent more likely to die of breast cancer than those who stayed within five pounds of their original weight, according to Hazel B. Nichols, a doctoral student in epidemiology at Johns Hopkins Bloomberg School of Public Health in Baltimore. Women increased their death risk by 14 percent for every 11 pounds they gained after diagnosis. The study, party of the continuing Collaborative Women’s Longevity study, looked at the body mass index(BMI) of 4,020 breast cancer patients from 1988 to 2001. Those categorized as obese—having a BMI of 30 or above—were 2.5 times more likely to die of breast cancer.
Nichols says receptor status was not required information in the statewide cancer registries on which the study was based, so that data was not available to researchers. Exercise and diet, however, have both been previously connected to hormone-negative breast cancer. The Women’s Intervention Nutrition Study(WINS), which I have written about in previous posts, saw a 42 percent reduction in recurrence among postmenopausal hormone-negative patients who ate a low-fat diet. And the California Teachers Study found that long-term exercise—both strenuous (like running) and moderate (a brisk walk)—were associated with reduced risk of estrogen receptor-negative tumors. No amount of exercise affected the risk for estrogen receptor-positive tumors.