Amenorrhea and Menopause in Patients with Breast Cancer after Chemotherapy

PURPOSE: The probability of ovarian failure after cytotoxic chemotherapy in patients with breast cancer has not been well established in Korea. This study aimed to assess the rate of ovarian failure in a large cohort of Korean premenopausal patients with breast cancer 12 months after chemotherapy. METHODS: This retrospective cohort study included premenopausal women (aged 20−44 years) with breast cancer who underwent chemotherapy after surgery. The rates of treatment-related amenorrhea (TRA) and chemotherapy-induced menopause (CIM) at 12 months after chemotherapy were analyzed. RESULTS: A total of 237 patients met the inclusion criteria. The rate of TRA was 61.6% and that of CIM was 13.1% at 12 months after chemotherapy. The rates of TRA and CIM were 28.0% and 4.0%, respectively, in women aged 25−34 years, and they gradually increased up to 75.9% (TRA) and 15.8% (CIM), respectively, in women aged 40−44 years. The frequency of CIM was significantly lower than that of TRA in both age groups. In multivariate analyses, only tamoxifen use was significantly associated with a decreased risk of CIM (p < 0.001). Age of 40 years or higher and the regimens of doxorubicin plus cyclophosphamide followed by docetaxel or paclitaxel were associated with increased risk of TRA (p = 0.001 and p = 0.002, respectively). CONCLUSION: Marked discrepancy in the rates of CIM and TRA was observed in this study. Further, the age-specific frequency of CIM and TRA observed in this study is a reliable and practical estimate of the risks of CIM and TRA in the absence of gonadal protection.