Eligibility criteria for using menopausal hormone therapy in breast cancer survivors: a safety report based on a systematic review and meta-analysis.

IMPORTANCE: Menopause hormone therapy (MHT) effectively alleviates menopausal symptoms. However, it is generally not recommended for breast cancer survivors, although the scientific evidence is scarce.

OBJECTIVE: This study aimed to establish eligibility criteria for use of the MHT in breast cancer survivors based on a systematic review and meta-analysis of the literature.

EVIDENCE REVIEW: We conducted exhaustive literature searches until June 2022 in MEDLINE, The Cochrane Library, and EMBASE, using a tailored strategy with a combination of controlled vocabulary and search terms related to breast cancer survivors and MHT. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and assessed the risk of bias using the Cochrane and Risk of Bias in Non-randomized Studies - of Interventions tools. The quality of the evidence was graded according to grading quality of evidence and strength of recommendations criteria (A, high; B, moderate; C, low; and D, very low). We categorized MHT use into four levels: category 1 (no restrictions on use), category 2 (the benefits outweigh the risks), category 3 (the risks generally outweigh the benefits), and category 4 (MHT should not be used).

FINDINGS: A total of 12 studies met the eligibility criteria. Analysis of the three randomized clinical trials using combined MHT or tibolone revealed no significant differences concerning tumor recurrence (relative risk [RR], 1.46; 95% CI, 0.99-2.24). A combined analysis of randomized clinical trials, prospective, and retrospective trials found no elevated risk of recurrence (RR, 0.85; 95% CI, 0.54-1.33) or death (RR, 0.91; 95% CI, 0.38-2.19). The eligibility criteria for patients with hormone receptor (HR)-positive tumors fell into categories 3B and 3C for combined MHT or estrogen alone and 4A for tibolone. For HR-negative tumors, the category was 2B and 2C.

CONCLUSIONS AND RELEVANCE: Our findings suggest that MHT could be a viable treatment alternative for breast cancer survivors experiencing menopausal symptoms, especially those with HR-negative tumors. Personalized management is recommended for each peri/postmenopausal woman facing a diminished quality of life because of menopause symptoms. Further randomized trials are needed before considering changes to current standards of care.