Nearly All Types of Menopausal Hormone Therapy Tied to Higher Breast Cancer Risk

By Amy Orciari Herman

Edited by William E. Chavey, MD, MS

All types of menopausal hormone therapy (HT), except vaginal estrogen, are associated with increased breast cancer risk, according to a large meta-analysis in the Lancet.

Researchers examined prospective data on over 100,000 postmenopausal women who developed breast cancer. Among the other findings:

• Excess risk for breast cancer was greater for estrogen-progestogen combinations than for estrogen-only formulations.

• Breast cancer risk increased with duration of HT use, but among current users, risk was elevated even during the first 4 years of use (for example, 1–4 years of estrogen-progestogen was associated with a 60% increased risk relative to nonuse).

• Increased breast cancer risk persisted more than 10 years after stopping HT.

Dr. Andrew Kaunitz will take a closer look at these findings in NEJM Journal Watch Women's Health. Be on the lookout for his coverage.