Although postmenopausal hormones have beneficial effects on mood, libido, and bone health, the increased risk of breast cancer likely outweigh these benefits.

During the past 20 years, estrogen plus testosterone has become an increasingly popular form of postmenopausal hormone therapy. However, little is known about its effects on breast cancer risk. In the Nurses’ Health Study, we found that women who used estrogen plus testosterone were about twice as likely to develop breast cancer as women who had never used postmenopausal hormones. This increase in risk was comparable to — or even slightly greater than — that seen with estrogen plus progesterone. Although postmenopausal hormones have beneficial effects on mood, libido, and bone health, the increased risk of breast cancer likely outweigh these benefits. (Tamimi R et al. Arch Intern Med2006; 166:1483)