Changes in ovarian function in premenopausal women with breast cancer undergoing adjuvant TC (docetaxel and cyclophosphamide) chemotherapy during a brief period of amenorrhea around the last chemotherapy cycle

PURPOSE Docetaxel, a chemotherapeutic agent, induces high rates of transient chemotherapy-induced amenorrhea (CIA) when used as adjuvant chemotherapy for premenopausal women with breast cancer. Clinical laboratory data to assess the hormonal environment implicated in inducing transient CIA was assessed. METHODS An observational study was conducted in 35 premenopausal women with hormone-responsive breast cancer who were receiving adjuvant docetaxel/cyclophosphamide (TC) chemotherapy. Serum estradiol and follicular stimulating hormone (FSH) levels were measured at one (n = 6) or two (n = 29) time point(s) around the completion of chemotherapy. RESULTS As early as week 6 after the start of chemotherapy, just before the third TC cycle, serum estradiol levels were invariably suppressed (median of 5.5 pg/ml, n = 15, range <5-18.7 pg/ml) and FSH levels increased (median of 63.9 mIU/ml, range 24.5-127.4 mIU/ml), indicative of ovarian suppression to the menopausal levels. Subsequently, at 9 and 12 weeks, serum estradiol levels were suppressed to a median of 6.6 pg/ml (n = 49, range <5-17.3 pg/ml), while FSH levels were high (median of 66.8 mIU/ml, range 29.2-134.5 mIU/ml). There was a significant Spearman's correlation (ρ = 0.95, n = 29, p < 0.01) of high serum FSH levels (24.5-134.5 mIU/ml) between two time points of repeated measurements in 29 patients. TC chemotherapy induced rapid ovarian suppression with the formation of a high and stable plateau in serum FSH levels from week 6 to week 12. CONCLUSIONS Recovery from transient CIA post-therapy may be partially attributed to high, stable FSH levels that occurred as early as after completion of the second TC chemotherapy cycle.