The prevalence of menopausal level of follicle-stimulating hormone (FSH) in peri-menopausal breast cancer patients aged between 45 and 60 years

Objectives Breast cancer is the global most common cancer among women. One of the major breakthrough in systemic therapy for breast cancer is the development of an aromatase inhibitor (AI). An AI is indicated as an adjuvant treatment and a palliative therapy, specifically for hormonal-receptor positive (HR+) breast cancer women with complete loss of ovarian function. Since there are many definitions of post-menopause, an AI is commonly falsely prescribed based on either a patient’s age or menstrual history alone and it may lead to unexpectedly poorer outcomes. The follicle-stimulating hormone (FSH) level of more than 40 IU/L is one of the acceptable definition of menopause. The investigators intended to determine the prevalence of menopausal level of FSH among women aged 45-60 years with breast cancer and its predictive factors. Material and Methods This was a cross-sectional study conducted among peri-menopausal HR+ breast cancer patients aged 45-60 years who were treated either in an adjuvant or metastatic setting in Vajira Hospital. Any patients still having regular periods, already receiving an AI, fulvestrant, or a gonadotropin hormone releasing hormone (GnRH) analogue, or not castrated either by oophorectomy or radiation were excluded. Results There were 90 patients in this study. FSH levels in 46 of them (51%) were menopausal. Only subgroups using tamoxifen and a history of rare or no menstruation for more than 2 years had a statistically significant trend toward having menopausal FSH levels. Conclusion Physicians should not rely on a patient’s age or menstrual history to determine post-menopausal status. These results emphasize strict validation of menopausal status prior to prescribing an AI or fulvestrant to peri-menopausal breast cancer patients.