Breast Cancer Risk: One Size May Not Fit All

According to researchers from the University of Southern California, after prolonged hormone replacement therapy, or HRT, breast cancer risk significantly increases.  Weight also plays a role in the equation, but probably not in the way you’d expect.

Study Details

For the study researchers analyzed data comprised from a group of 3,000 women over the course of over ten years (1995-2006).  Women who underwent estrogen therapy for 15 years or longer increased breast cancer risk by 19%, while those who took estrogen in tandem with progestin increased their risk of the disease by 83%.

The study confirms current recommendations that women who choose HRT to treat menopausal symptoms take as little as possible and only for a limited duration. 

Prior studies, such as the Women’s Health Initiative, declared the same results:  traditional HRT increases breast cancer risk.   Since the Women’s Health Initiative was first published, a steady, tapering off of HRT has been matched with a decline in breast cancer. 

Adiposity and Breast Cancer

Interestingly, the USC study showed that thinner women are at a greater risk of breast cancer after HRT than are obese women.  The researchers did not determine or postulate why this is the case.  This finding seems counterintuitive in light of an ACS report published last year.

Specifically, the American Cancer Society presented a study conducted by the West Virginia Robert C. Byrd Health Sciences Center that revealed that a poor, long-term prognosis of breast cancer is associated with patients who have pre-existing obesity, and/or post-op weight gain.  Why?  Because adipose tissue provides a fertile environment for estrogen synthesis; although the studies are not necessarily contradictory, it is apparent that further research is needed.

Ahmed Jemal, the lead for the West Virginia study, discovered that women who gain 22 pounds after menopause face an increased risk of 18% of developing breast cancer.

Conversely, Jemal’s report states that a decline in the breast cancer mortality rate could be fueled by maintaining a healthy weight and minimizing alcohol, another known risk factor.

Clearly, weight management, HRT, and other variables such as physical activity and alcohol consumption, play an active role when it comes to breast cancer risk.  This is fortunate, because lifestyle issues such as these fall under the realm of risk factors we can control.