Response to Media Reports on Hormone Replacement Therapy and Breast Cancer
A study published in a recent issue of the Journal of the American Medical Association (JAMA) on the increased risk of breast cancer and HRT is drawing a great deal of attention from the lay press. As is often the case, patients turn to their physicians for advice, answers, and information. Please read our short summary about the study and some key points about the study.
- The study was published in the 20 October 2010 issue of JAMA and it is entitled "Estrogen Plus Progestin and Breast Cancer Incidence and Mortality in Postmenopausal Women."
- The abstract for the article can be found here
- The study is part of continuing research from the Women's Health Initiative (WHI) research on estrogen plus progestin hormone replacement therapy.
- The original WHI was terminated in 2002 when initial results found an increased risk of breast cancer in women taking HRT vs. placebo.
- Data was collected over 8 years after the study ended to further determine long term effects of HRT therapy. Of the 12,788 women followed during that period, the study published today showed:
- An increased risk of breast cancer (385 taking HRT vs. 293 taking placebo).
- Breast cancers were more commonly diagnosed in an advanced stage with more lymph node involvement.
- Twice as many women who took HRT died within the follow-up period compared with those who took placebo (25 vs. 12 deaths – 2.6 deaths from breast cancer for every 10,000 women vs. 1.3 deaths from breast cancer for every 10,000 women, respectively).
Key Limitations to the Study
- The study only looked at long term use of HRT on breast cancer.
- The published study and an accompanying editorial specifically state that additional studies need to be done to see if lower doses or shorter durations of HRT can reduce menopausal symptoms without increasing cancer risk.
- The study tracked patients taking a very specific combination of conjugated equine estrogens and medroxyprogesterone. It did not track or review patients taking other types of estrogens, and progestins or progesterone.
- The estrogen used by the patients in the study was Premarin (conjugated equine estrogens 0.625mg). Not estriol, estradiol or other estrogens used by compounding pharmacies. Premarin is not considered to be a "bio-identical" hormone.
- Medroxyprogesterone acetate 0.25mg was used, not progesterone as some media outlets have reported.
- Neither the estrogen nor the progestin taken by the patients in this study are bioidentical hormones.
- Bioidentical hormones were not studied.
- Although "twice as many died" sounds alarming, the actual statistics are 2.6 deaths for every 10,000 women vs. 1.3 deaths for every 10,000 who weren't taking the drug combination.
- HRT has definitively been linked to an increased risk of breast cancer; however, women not taking HRT also get breast cancer. Other contributing factors include genetics and smoking.
- All women should conduct regular breast self-examinations, schedule and have mammograms done when recommended, and see a physician on a regular basis to assess and maintain breast health.
- Patients should always discuss their concerns about their medicines with their pharmacist and their physician before abruptly stopping or changing their medications, including HRT or BHRT.
