title: Prognostic impact of chemotherapy-induced amenorrhea on premenopausal breast cancer: a meta-analysis of the literature.
abstract: OBJECTIVE
  We conducted this meta-analysis of published data to assess the exact prognostic value of adjuvant chemotherapy-induced amenorrhea (CIA) as a prognostic factor for premenopausal breast cancer.
  
  
  METHODS
  We searched for all relevant studies published before May 2014 in the PubMed, OVID, and EMBASE databases. Relative risks (RRs) were used to estimate the association between CIA and various survival outcomes, including disease-free survival (DFS) and overall survival (OS).
  
  
  RESULTS
  This meta-analysis identified 13 eligible studies including 5,513 cases and 2,008 controls for DFS and 5 eligible studies including 2,331 cases and 776 controls for OS. Results demonstrated that CIA is associated with improved DFS (RR, 0.67; 95% CI, 0.61-0.74; P < 0.001) and OS (RR, 0.60; 95% CI, 0.50-0.72; P < 0.001). In subgroup analyses, CIA was found to affect DFS (RR, 0.73; 95% CI, 0.61-0.88; P = 0.001) in estrogen receptor (ER)-positive patients; however, similar results were not observed in ER-negative patients (for DFS: RR, 0.97; 95% CI, 0.66-1.41; P = 0.858). Participants with CIA achieved a significantly better prognosis than participants without CIA, irrespective of nodal status, chemotherapy regimen, endocrine therapy, or publication year.
  
  
  CONCLUSIONS
  This meta-analysis clarifies that CIA contributes to improved prognosis in premenopausal women with ER-positive breast cancer and is at least partially responsible for the benefits of adjuvant chemotherapy in these women, which induce chemical castration.
authors.affiliation: 1Department of Gynecology, Zhejiang Cancer Hospital, Hangzhou, China 2Department of Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, China 3Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China 4Breast Cancer Center, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zhou
authors.forename: Wenjin
authors.initials: W
authors.lastname: Yin
authors.forename: Yueyao
authors.initials: Y
authors.lastname: Du
authors.forename: Zhenzhou
authors.initials: Z
authors.lastname: Shen
authors.forename: Jingsong
authors.initials: J
authors.lastname: Lu
mesh_terms: D000367:Age Factors; D000568:Amenorrhea / Q000139:chemically induced* / Q000453:epidemiology; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy*; D017024:Chemotherapy, Adjuvant / Q000009:adverse effects; D005260:Female; D006801:Humans; D009367:Neoplasm Staging; D017697:Premenopause; D011379:Prognosis; D012307:Risk Factors