Women who have gone through menopause who lose a relatively modest amount of weight significantly reduce their risk of developing breast cancer, according to results reported at the 2017 San Antonio Breast Cancer Symposium.

Women (after menopause) who lost just 5 percent of their body weight over 3 years experienced a 12 percent reduction in their relative risk of developing breast cancer. Researchers from City of Hope (Duarte, CA, USA) examined the connection between weight change and invasive breast cancer risk among 61,335 postmenopausal women in the Women’s Health Initiative Observational Study with no prior breast cancer and with normal mammograms. They then characterized weight change over three years as stable, loss, or gain.

Women with weigh loss of 5 percent or more dropped their risk of developing breast cancer by nearly one-eight (relative risk 0.88). For women who lost 15 percent or more, the risk dropped by a stunning one-third (risk 0.63x that of someone without weight loss). And those who had weight grain significantly increased the risk of triple-negative breast cancer, a particularly aggressive type that does not “feed” on estrogen or progesterone, and does not have too many HER-2 receptors. This risk increased by a factor of 1.54.

I’m Dr. Michael Hunter.