Weight loss may help lower postmenopausal women’s risk of developing high grade breast cancer
In a study of postmenopausal women, participants who lost weight had a lower risk of developing high grade breast cancer than those who maintained or gained weight.
Findings of the study were published in CANCER, a peer-reviewed journal of the American Cancer Society.
Although obesity has been strongly related to breast cancer risk, studies examining whether weight loss might reduce postmenopausal women’s risk have provided mixed results.
Researchers analyzed information on 61,335 women participating in the World Health Initiative Observational Study who had no prior breast cancer and had normal mammogram results. The women’s body weight, height, and body mass index were assessed at the start of the study and again 3 years later.
Women with weight loss of about 5 percent had a 12 percent lower breast cancer risk compared with women whose weight remained stable
Breast cancer incidence by anatomical site
There were 3,061 new cases of invasive breast cancer diagnosed over a follow-up period of 11.4 years. Women with weight loss of about 5 percent had a 12 percent lower breast cancer risk compared with women whose weight remained stable. Weight gain of  about 5 percent, on the other hand, was not only associated with risk of breast cancer overall but was associated with a 54 percent higher incidence of triple negative breast cancer.
“Our study indicates that moderate, relatively short-term weight reduction was associated with a statistically significant reduction in breast cancer risk for postmenopausal women,” said lead author, Dr. Chlebowski MD, PhD, at Hope National Medical Center in Duarte, California.
“These are observational results, but they are also supported by randomized clinical trial evidence from the Women’s Health Initiative Dietary Modification trial where, in a randomized clinical trial setting, adopting a low-fat dietary pattern that was associated with a similar magnitude of weight loss resulted in a significant improvement in breast cancer overall survival. These findings, taken together, provide strong correlative evidence that a modest weight loss program can impact breast cancer,” Dr. Chlebowski added.
