Menopausal Symptom Burden in Premenopausal Breast Cancer Patients: Interaction of Chemotherapy and Ovarian Function Suppression on Tamoxifen Treatment.

Aim: To compare menopausal symptoms between tamoxifen alone and tamoxifen with ovarian function suppression (OFS) over 12 months, identifying related factors.

Methods: This prospective, observational study included 209 premenopausal patients with breast cancer on tamoxifen, recruited from Asan Medical Center, Republic of Korea. We collected demographic and clinical information from the participants' medical records and assessed menopausal symptoms using the Korean Menopause Rating Scale (MRS) at 3-, 6-, and 12-months postdiagnosis.

Results: Of the 209 participants, 27.8% were administered tamoxifen in conjunction with OFS. Compared with the tamoxifen alone group, the tamoxifen plus OFS group had lower baseline MRS scores but higher scores at 6 and 12 months, and the scores showed a plateau within a year for both groups. Factors contributing to higher MRS scores at 6 months included the baseline MRS score (estimate, -0.326; standard error, 0.077) and addition of OFS (estimate, 6.084; standard error, 1.306; P < .001 for both). A significant interaction between OFS and prior chemotherapy was identified, with the OFS impact being significantly notable only in patients without prior chemotherapy (estimate, -6.643; standard error, 2.946; P = .025).

Conclusions: Addition of OFS to tamoxifen in premenopausal patients with breast cancer can exacerbate menopausal symptoms relative to those when tamoxifen is used alone, especially in patients without prior chemotherapy. Thus, personalized treatment decisions about ovarian function suppression should consider potential symptom burdens, particularly for chemotherapy-naive patients, to balance treatment efficacy and quality of life.