Breast cancer and hormone replacement in postmenopausal females

January 01, 0001

Breast cancer and hormone replacement in postmenopausal females

The Women's Health Initiative (WHI) raised concerns about the safety of hormonal replacement in postmenopausal women. These US researchers examined the longer term effects of therapy with estrogen plus progestin on breast cancer incidence and mortality in the WHI participants. Of the original 16 608 postmenopausal women aged 50 to 79 years randomly assigned to receive combined conjugated equine estrogens, 0.625 mg/d, plus medroxyprogesterone acetate, 2.5 mg/d vs placebo pill, 12 788 (83%) of the surviving participants were followed for a mean of 11 years.

The researchers found: "In intention-to-treat analyses including all randomized participants and censoring those not consenting to additional follow-up on March 31, 2005, estrogen plus progestin was associated with more invasive breast cancers compared with placebo (385 cases {0.42% per year} vs 293 cases {0.34% per year}, hazard ratio {HR} 1.25). Breast cancers in the estrogen-plus-progestin group were similar in histology and grade to breast cancers in the placebo group but were more likely to be node-positive (81 {23.7%} vs 43 {16.2%}, respectively, HR 1.78). There were more deaths directly attributed to breast cancer (25 deaths {0.03% per year} vs 12 deaths {0.01% per year}, HR 1.96) as well as more deaths from all causes occurring after a breast cancer diagnosis (51 deaths {0.05% per year} vs 31 deaths {0.03% per year} ,HR 1.57) among women who received estrogen plus progestin compared with women in the placebo group."

The researchers concluded: "Estrogen plus progestin was associated with greater breast cancer incidence, and the cancers are more commonly node-positive. Breast cancer mortality also appears to be increased with combined use of estrogen plus progestin."

More cautionary data on the use of hormone replacement in postmenopausal females and the risk of breast cancer

For the full abstract, click here.

JAMA 304(15):1684-1692, 20 October 2010 © 2010 American Medical Association
Estrogen Plus Progestin and Breast Cancer Incidence and Mortality in Postmenopausal Women. Rowan T. Chlebowski, Garnet L. Anderson, Margery Gass, et al.

Category: X. Female Genital System, Breast. Keywords: breast cancer, hormone replacement, estrogen, progestin, Women’s Health Initiative, extended follow up of randomized controlled trial, journal watch.
Synopsis edited by Dr Paul Schaefer, Toledo, Ohio. Posted on Global Family Doctor 5 November 2010

Pearls are an independent product of the Cochrane primary care group and are meant for educational use and not to guide clinical care.

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