The risk of premature menopause induced by chemotherapy for early breast cancer

The objectives of this retrospective case series were to determine the prev alence and timing of menstrual abnormalities in early-stage breast cancer p atients undergoing adjuvant methotrexate or anthracycline-based chemotherap y and to more fully assess the possible mechanism of the amenorrhea reporte d after chemotherapy. One hundred forty-two premenopausal patients undergoi ng adjuvant chemotherapy were analyzed for patient age, breast cancer stage , type of chemotherapy and menstrual abnormalities before, during, and afte r chemotherapy completion. A 24-month minimum follow-up after chemotherapy completion was available for all patients. One hundred nine of 142 patients were evaluable. Sixty-nine patients (46 node negative, 23 node positive) r eceived methotrexate-based chemotherapy, 33 patients (3 node negative, 30 n ode positive) received anthracycline-based chemotherapy, and 7 patients rec eived both treatments tall node positive). Amenorrhea occurred in about a t hird of patients during chemotherapy (methotrexate groups 31% anthracycline group 33%), and a higher proportion were amenorrheic 1 year after chemothe rapy was completed (methotrexate group 45%, anthracycline group 46%). Abnor malities were more likely to occur in older premenopausal patients (Chi squ are = 6.18, p < 0.05), although 28% of patients under age 35 developed pers istent abnormal menses. In some amenorrheic patients, follicle-stimulating hormone (FSH) levels were decreased within 6 months of chemotherapy (24.4 I U). The levels tended to be higher after chemotherapy (59.1 IU), suggesting ovarian failure. Menstrual abnormalities and menopause will frequently occ ur in premenopausal early-stage breast cancer patients, with 30% of all pat ients amenorrheic 1 year after chemotherapy.