Previous research proved exercise reduces the risk of breast cancer, and now a new study adds to that finding. Researchers say exercise may lower a woman's risk of developing breast carcinoma in situ -- a cluster of abnormal cells that can develop into invasive breast cancer if left untreated.
Researchers from the American Cancer Society studied more than 1,500 women between 35 and 64 years old. More than 550 participants had been previously diagnosed with BCIS. Of the more than 1,000 women in the control group, around 600 had been screened within two years of starting the study. Researchers asked the participants questions about their involvement in activities such as walking, jogging, dancing and swimming to calculate a weekly activity log for each woman.
Results of the study show women who exercised had a 35-percent lower risk of developing BCIS than those who were inactive. Women who exercised more than four hours a week had a 47-percent lower risk of BCIS than women who did not exercise. However, researchers say exercise did not reduce the risk of BCIS in women who had a family history of breast cancer.
Some researchers believe exercise reduces the risk of BCIS by lowering levels of female hormones. Leslie Bernstein, Ph.D., co-author of the study, says, "Although we presume that physical activity works through a hormonal means to reduce BCIS risk, this may not be an important mechanism for women who may have a hereditary form of the disease."