Impact of HT in women with an elevated risk of breast cancer
Abenhaim and colleagues could not evaluate the effect of HT in women with a baseline elevated risk of breast cancer.9 For these women, HT may be recommended after premature surgical menopause due to increased risks for coronary heart disease, osteoporosis, genitourinary syndrome of menopause, and cognitive changes when estrogen is not taken postsurgery through to at least the average age of menopause, considered age 51.18,19
Marchetti and colleagues reviewed 3 clinical trials that assessed breast cancer events in 1,100 BRCA gene mutation carriers with intact breasts who underwent risk-reducing salpingo-oophorectomy (RRSO) who used or did not use HT.20 For BRCA1 and BRCA2 mutation carriers who received HT after RRSO, no elevated risk of breast cancer risk was seen (HR, 0.98; 95% CI, 0.63–1.52). There was a nonsignificant reduction in breast cancer risk for the estrogen-alone users compared with EPT HT (OR, 0.53; 95% CI, 0.25–1.15). Thus, short-term use of HT, estrogen alone or EPT, does not appear to elevate the risk of breast cancer after RRSO in these high-risk women.
Individualizing HT for menopausal symptoms
The data presented provide reassuring evidence that longer-term use of ET does not appear to increase breast cancer risk, regardless of the type of estrogen (CEE or estradiol).4,5,9,11 For women with a uterus, micronized progesterone has less (if any) effect on breast cancer risk. By contrast, the use of synthetic progestins (such as MPA), when combined with estrogen, has been associated with a small but real increased breast cancer risk.
The most evident benefit of HT is in treating vasomotor symptoms and preventing bone loss for those at elevated risk in healthy women without contraindications who initiate systemic HT when younger than age 60 or within 10 years of menopause onset. Benefit and risk ratio depends on age and time from menopause onset when HT is initiated. Hormone therapy safety varies depending on type, dose, duration, route of administration, timing of initiation, and whether, and type, of progestogen is used. Transdermal estradiol, particularly when dosed at 0.05 mg or less, has been shown to have less thrombotic and stroke risk than oral estrogen.21
Individualizing treatment includes using the best available evidence to maximize benefits and minimize risks, with periodic reevaluation of benefits and risks of continuing or discontinuing HT or changing to lower doses. ObGyns who follow best practices in prescribing systemic HT can now help menopausal patients with bothersome symptoms take advantage of systemic HT’s benefits while providing reassurance regarding menopausal HT’s safety.18 Transdermal therapy is a safer option for women at elevated baseline risk of venous thrombosis (for example, obese women) and older patients. Likewise, given its safety with respect to risk of breast cancer, the use of micronized progesterone over synthetic progestins should be considered when prescribing EPT to women with an intact uterus.
WHAT THIS EVIDENCE MEANS FOR PRACTICE
We can replace fear of HT with evidence-based discussions.22 For women with prior hysterectomy who have menopausal symptoms that impact their quality of life, ET at menopause does not appear to increase the risk of breast cancer. For women with an intact uterus who are considering use of estrogen and progestogen, extended-duration use of combination HT with synthetic progestins slightly elevates the risk of breast cancer, while the use of micronized progesterone does not appear to elevate breast cancer risk. Likewise, transdermal estrogen does not appear to elevate thrombosis risk.
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