Hormone Therapy's Impact on Incident and Fatal Breast Cancer at 20 Years' Follow-Up

Estrogen alone reduced incidence of (and mortality from) invasive breast cancer, while combination estrogen-progestin therapy elevated incidence of (but not mortality from) this malignancy.

Earlier reports from the Women's Health Initiative (WHI) randomized trials of estrogen-only (ET) and estrogen-progestin (EPT) hormone therapy (HT) found that, compared with placebo, ET reduced risk for invasive breast cancer but EPT increased risk among the 27,347 participants (mean age at baseline, 63; NEJM JW Women's Health Nov 2013 and JAMA 2013; 310:1353). Now, WHI investigators have analyzed longer-term data (median cumulative follow-up >20 years), allowing assessment of whether these trends persist — and whether they translate into an effect on risk for death from breast cancer.

In the ET trial (10,739 participants with prior hysterectomy), 238 vs. 296 cases were diagnosed in women in the ET versus placebo groups (annualized incidence,…

Reviewing Author

Andrew M. Kaunitz, MD

Disclosures

RoyaltiesUpToDate

Grant/Research SupportMerck, Mithra, Medicines360

Editorial BoardsContraception; Menopause; Contraceptive Technology Update; OBG Management; Medscape OB/GYN & Women’s Health

Andrew M. Kaunitz, MD

Disclosures

RoyaltiesUpToDate

Grant/Research SupportMerck, Mithra, Medicines360

Editorial BoardsContraception; Menopause; Contraceptive Technology Update; OBG Management; Medscape OB/GYN & Women’s Health

Hormone Therapy's Impact on Incident and Fatal Breast Cancer at 20 Years' Follow-Up

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Reviewing Author