The WISDOM trial and the WHI (Women's Health Initiative) studied HRT in postmenopausal women. Regarding the risk-benefit profile of combined estrogen-progestogen HRT versus estrogen-only HRT (in hysterectomised women), which specific malignancy risk reversal is central to current prescribing guidance?
- A Estrogen-only HRT has higher breast cancer risk than combined HRT
- B Both combined and estrogen-only HRT equally increase colorectal cancer risk
- C Combined (estrogen + progestogen) HRT significantly increases breast cancer risk; estrogen-only HRT in hysterectomised women does NOT significantly increase (and may reduce) breast cancer risk ✓
- D Combined HRT reduces cardiovascular risk more than estrogen-only HRT in all age groups
Explanation
WHI data revealed a nuanced risk profile: combined (conjugated equine estrogen + medroxyprogesterone acetate) HRT significantly increased breast cancer risk (HR 1.26 in the combined arm), while the estrogen-only arm (women with prior hysterectomy) showed a non-significant trend toward REDUCED breast cancer risk (HR 0.77 at 7 years, subsequently confirmed in extended follow-up). This finding — that the progestogen component drives the breast cancer risk rather than estrogen alone — profoundly changed menopause management: micronised progesterone and dydrogesterone are now preferred over synthetic progestogens (medroxyprogesterone acetate, norgestrel) due to potentially lower associated breast cancer risk in observational data (E3N cohort, CGHFBC analysis).
Reference: Shaw's Textbook of Gynaecology, 17th ed.
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Written and medically reviewed by the StethoPrep medical team.