Impact of chemotherapy-induced amenorrhea in breast cancer patients: the evaluation of ovarian function by menstrual history and hormonal levels

BACKGROUND Chemotherapy-induced amenorrhea (CIA) is one of the most frequent therapy-related adverse events observed in breast cancer patients who have undergone chemotherapy. Although the characteristics of CIA have been studied in Western countries, little is known about CIA in Asian. We conducted a retrospective analysis to assess the characteristics and influencing factors of CIA and its association with menopause in Chinese women who underwent adjuvant chemotherapy for early-stage breast cancer. METHODS Seventy-three premenopausal women who underwent adjuvant chemotherapy for early stage (stages I to III) breast cancer were analyzed. Patient clinical characteristics, treatment regimes, menstrual information, and serum hormone values were collected retrospectively. Characteristic factors relevant to the onset of CIA and menopause were also estimated. RESULTS Approximately 83.6% of patients developed CIA. Older patients (>40 years old) had higher CIA incidence compared with younger patients (P <0.0001). The onset of menopause was correlated with age (P <0.0001) and tamoxifen use (P = 0.0313). On the basis of the Kaplan-Meier analysis, a significant difference was observed in the time of onset of permanent amenorrhea as determined by menstrual history and hormone levels (P = 0.0028). In women aged 46 to 49 years, the beginning of permanent amenorrhea was detected earlier via the clinical method than via the hormonal method (2 months versus 23 months, P <0.0001). In the analysis of patients ≥50 years old, the median time to detection of permanent amenorrhea was 19 months in the hormonal test and 2 months in the clinical test (P = 0.0112). CONCLUSIONS Age at diagnosis is a predictor of the onset of amenorrhea and transformation into menopause among premenopausal breast cancer patients. Adjuvant tamoxifen therapy substantially affects the onset of menopause. A delay of the onset of serum hormone postmenopausal status was observed compared with clinical symptoms. This interval was approximately 21 months in patients aged 46 to 49 years and 17 months in patients aged over 50 years. This interval is significant in the clinical estimate of the menstrual status.