NSAS-BC02 substudy of chemotherapy-induced amenorrhea (CIA) in premenopausal patients who received either taxane alone or doxorubicin(A) cyclophosphamide(C) followed by taxane as postoperative chemotherapy.

BACKGROUND: Chemotherapy-induced amenorrhea (CIA) is one of the critical side effects from the chemotherapy in premenopausal patients with breast cancer. The goals of our study are the following: (1) to investigate the factors affecting the incidence of CIA; and (2) to evaluate the prognostic role of CIA in premenopausal patients with breast cancer. METHODS: We conducted a post hoc retrospective substudy to examine the incidence of the CIA and the relationship between CIA and prognosis in NSAS-BC02 that compared taxane alone to Doxorubicin(A) Cyclophosphamide(C) followed by taxane in postoperative patients with node-positive breast cancer RESULTS: Of 395 premenopausal women, 287 (72.7%) had CIA due to protocol treatment. Regarding type of protocol regimen, proportion of CIA was 76.9% in AC Paclitaxel(P), 75.2% in AC Docetaxel(D), 62.8% in PTX, and 75.2% in DTX. Predictive factors of CIA were age increase by 5 years (OR 1.50), ER positivity (OR 2.08), and HER2 3 + ( OR 0.40) according to logistic regression analysis. According to the log rank test and the Cox proportional hazards model, CIA group had significantly better disease-free survival than non-CIA group (P < .0001). However, according to time-dependent Cox model that was used to reduce guarantee-time bias, CIA was not a statistically significant prognostic factor in both ER-positive and ER-negative patients. CONCLUSION: Treatment with taxane alone caused high frequency of CIA in premenopausal women with breast cancer. CIA did not turn out to be an independent prognostic factor, taking guarantee-time bias into consideration. Further clinical studies are needed to validate these findings.