A nearly 20-year observational study involving more than 44,700 black women nationwide found that regular vigorous exercise offers significant protection against development of an aggressive subtype of breast cancer. The findings from the Black Women's Health Study are being presented at the 2013 San Antonio Breast Cancer Symposium.
The research team, co-led by scientists at Georgetown Lombardi Comprehensive Cancer Center and Boston University, found that black women who engaged in brisk exercise for a lifetime average of three or more hours a week had a 47 percent reduced risk of developing estrogen receptor-negative (ER-) breast cancer compared with those exercising an average of one hour per week, according to a preliminary analysis. The results will be updated at the meeting.
This form of breast cancer, which includes HER2-positive and triple negative tumors, is linked to both higher incidence and mortality in black women, relative to white women. ER- tumors do not respond to hormone therapies used to treat tumors that have the estrogen receptor.
"These findings are very encouraging. Knowing that exercise may protect against breast cancers that disproportionately strike black women is of great public health importance," says Lucile Adams-Campbell, PhD, professor of oncology and associate director of Minority Health & Health Disparities Research at Georgetown Lombardi.
"We all want to do what we can to reduce our risk of disease and improve our health, and along with other well known benefits, we now show that exercise can possibly stave off development of potentially lethal breast cancer in black women," she says.
Exercise, at any level, appeared to have no effect on development of estrogen receptor-positive (ER+) in these women, the researchers say. They cannot offer a reason why because their study was not designed to answer this question. They also cannot speculate on whether vigorous exercise in white women would have any effect.
The 44,704 women who participated in the study were 30 years or age or older.