Breast Cancer Rates Decline After Stopping Hormone Replacement

by Mona Saint MD

Many women struggle with menopausal symptoms and opt to take hormone replacement during this time. Hormone replacement consists of estrogen and progesterone and it can be taken orally, via patches, and as creams and gels. There are always many questions regarding hormones, given how difficult the perimenopause and menopause can be, and with the various risks and benefits of hormone therapy. The Women’s Health Initiative was a large study that found that women using Premarin 0.625mg and Provera 2.5mg of hormone replacement treatment had higher rates of breast cancer (26% increased risk) than those who did not use any hormones. After this study was released many women stopped hormone therapy in the U.S., and breast cancer rates have decreased nationally since the study in 2002. In this follow-up study, the same patients who were in the Women’s Health Initiative were followed and found to have their breast cancer risk drop to the same level as women who did not take hormones 2 years after stopping treatment. One cannot prove a cause and effect relationship, but it is compelling. This study only looked at one type of hormone replacement therapy, and so it is unknown how the other types of estrogen and progesterone on the market affect the risk of breast cancer.

The Women’s Health Initiative was a study of older postmenopausal women, who have stopped having periods for 1 year or more and on average were 63 years old (ranging from 50-79 years). These same risks have not been found in younger and premenopausal women taking birth control pills and hormones, nor has it been found in the vaginal estrogens, or in women who have had hysterectomies who are taking estrogen only. (Progesterone is given to women with a uterus in combination with estrogen to protect the uterus from cancer while on estrogen). Currently we counsel patients about these risks and warn that any estrogen and progesterone combination including the “bio-identical” hormones postmenopausally (especially over age 60) could potentially pose these risks. However, many women cannot function during menopause without at least short term use of hormones and these are still the most effective treatment for menopausal symptoms. We try to use the lowest dose possible to control symptoms for the shortest amount of time needed, if possible. If you taking hormones, discuss with your doctor the various options and dosages, remember to perform monthly self breast exams, and see your physician for annual examinations and mammogram screening.

Chlebowski RT, et al “Breast cancer after use of estrogen plus progestin in postmenopausal women”. New England Journal of Medicine 2009.

Menopausal Reading Resources:
1. NIH Hormone Treatment Facts
2. Up To Date Patient Information on Menopause