What lies behind chemotherapy-induced amenorrhea for breast cancer patients: a meta-analysis.

To evaluate the incidence of chemotherapy-induced amenorrhea (CIA) and its therapeutic impact in premenopausal breast cancer patients. A systematic search was performed to identify clinical studies that compared the incidence of CIA with different chemotherapy regimens and oncological outcomes with and without CIA. The fixed-effects and random-effects models were used to assess the pooled estimates. Heterogeneity and sensitivity analyses were performed to explore heterogeneity among studies and to assess the effects of study quality. A total of 15,916 premenopausal breast cancer patients from 46 studies were included. The cyclophosphamide-based regimens, taxane-based regimens, and anthracycline/epirubicin-based regimens all increased the incidence of CIA with pooled odds ratios of 2.25 (95 % CI 1.26-4.03, P = 0.006), 1.26 (95 % CI 1.11-1.43, P = 0.0003) and 1.39 (95 % CI 1.15-1.70, P = 0.0008), respectively. The three-drug combination regimens of cyclophosphamide,anthracycline/epirubicin, and taxanes (CAT/CET) caused the highest rate of CIA compared with the other three drug combinations (OR 1.41, 95 % CI 1.16-1.73, P = 0.0008). Tamoxifen therapy was also correlated with a higher incidence of CIA, with an OR of 1.48. Patients with CIA were found to exhibit better disease-free survival (DFS) and overall survival (OS) compared with patients without CIA. With respect to molecular subtype, this DFS advantage remained significant in hormone-sensitive patients (HR 0.61, 95 % CI 0.52-0.72, P < 0.00001). The current meta-analysis has demonstrated that anthracycline/epirubicin, taxanes, cyclophosphamide, and tamoxifen all contributed to elevated rates of CIA, and CIA was not merely a side effect of chemotherapy but was a better prognostic marker, particularly for ER-positive premenopausal early-stage breast cancer patients. However, this topic merits further randomized control studies to detect the associations between CIA and patient prognosis after adjusting for age, ER status, and other influential factors.