Chemotherapy-induced amennorrhea: Predictive markers of response to neoadjuvant chemotherapy in breast cancer.

281 Background: There is controversy about the benefit of chemotherapy-induced amenorrhea (CIA) in breast cancer. We investigated significance of CIA after neoadjuvant chemotherapy for predicting response to neoadjuvant chemotherapy in breast cancer patients. Methods: We reviewed the records of 198 premenopausal patients with breast cancer treated with neoadjuvant chemotherapy between January 2005 and December 2010. Chemotherapy-induced amenorrhea (CIA) was defined as serum FSH level ≥40 IU/L after completion of all scheduled neoadjuvant chemotherapy and prior to definitive surgery. Results: Among 198 breast cancer patients, 132 pts (66.7%) developed CIA after neoadjuvant chemotherapy. 156 pts (78%) underwent DA chemotherapy. The age of CIA patients was older than non-CIA patients (41.55±5.55 vs. 38.27± 6.86 years, p=0.001). The incidence of CIA after neoadjuvant chemotherapy was significantly higher in responder group (responder vs. nonresponder: 87 pts (74.4%) vs. 45 pts (55.6%); p=0.006). Additionally, FSH level after all scheduled neoadjuvant chemotherapy was significantly higher in responder group (FSH 56.41±32.41 mIU/ml vs. 45.76±30.31 mIU/ml; p=0.021). In univariate analysis, CIA (p=0.006) and total number of chemotherapy cycle regardless of chemotherapy regimen (p=0.04) were significantly predictive of tumor response. CIA was only significant predictive factor for tumor response after neoadjuvant chemotherapy on multivariate analysis (p=0.012). Conclusions: CIA is independent predictive markers of response to neoadjuvant chemotherapy in locally advanced breast cancer.