Women who lose weight after age 50 and keep it off have a lower risk of breast cancer than women whose weight remains stable, report researchers from the American Cancer Society and Harvard University.

In fact, the more weight study participants lost, the more their breast cancer risk fell. On the high end, those who lost 20 or more pounds were 26% less likely to develop the disease, said lead author Lauren Teras, Ph.D., from the ACS.

Meanwhile, women who lost 20 pounds or more and regained some (but not all) of the weight had a lower risk when compared with women whose weight remained stable.

Results were limited to women not using postmenopausal hormones, the researchers added.

The new study is the first with a large enough sample size to examine the link between weight loss and breast cancer risk with statistical precision, Teras said. She and her colleagues analyzed health data from more than 180,000 older women.

“Our results suggest that even a modest amount of sustained weight loss is associated with lower breast cancer risk for women over 50,” concluded Teras. “Even if you gain weight after age 50, it is not too late to lower your risk of breast cancer,” she said.

The study was published Tuesday in the Journal of the National Cancer Institute.