A person steps on a scale.
Approximately one-third of women in the United States are obese, which carries with it a known increased risk for high blood pressure, diabetes, orthopedic issues and breast cancer. (For Spectrum Health Beat)

Dropping weight might do more than make an older woman feel good. New research suggests it could lower her odds of 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 Dr. Rowan Chlebowski, from the City of Hope National Medical Center, in Duarte, California.

One oncologist said the findings are welcome news for millions of American women.

“Both obesity and breast cancer are medical issues that plague women in this country,” said Dr. Lauren Cassell, who directs breast surgery at Lenox Hill Hospital in New York City.

“Approximately one-third of women in the United States are obese, which carries with it a known increased risk for hypertension [high blood pressure], diabetes and orthopedic issues, to name just a few,” added Cassell, who wasn’t involved in the new research. “In addition, we know that one in eight women will develop breast cancer.”

So could dropping excess weight lead to lower breast cancer risk, too?

To find out, Chlebowski’s group tracked outcomes for over 61,000 postmenopausal women with no prior breast cancer and normal mammogram results. The women’s weight was checked at the start of the study and again three years later.

During an average follow-up of just over 11 years, about 3,000 new cases of invasive breast cancer were diagnosed in the group.

Women who lost 5 percent or more of their body weight had a 12 percent lower breast cancer risk than those whose weight remained the same, the findings showed.

In addition, weight gain of 5 percent or more was not associated with risk of breast cancer overall, but was associated with a 54 percent higher risk of triple negative breast cancer. However, the association doesn’t prove cause and effect.

The findings were published in the journal Cancer.

Chlebowski pointed out that “these are observational results, but they are also supported by randomized clinical trial evidence.”

Taken together, the studies “provide strong correlative evidence that a modest weight-loss program can impact breast cancer,” Chlebowski said in a journal news release.

Dr. Alice Police is regional director of breast surgery at Northwell Health Cancer Institute in Sleepy Hollow, N.Y. She stressed that for older women, menopause brings on many tough symptoms, including unwanted weight gain.

And the new study shows that, “as if that were not enough, we now seriously need to lose that weight so that we can minimize our chances of developing breast cancer,” Police said.