title: Chemotherapy treatment and survival in older women with estrogen receptor-negative metastatic breast cancer: a population-based analysis.
abstract: To investigate the survival benefit associated with chemotherapy receipt in older women with estrogen receptor-negative (ER-) Stage IV breast cancer.
  
  
  METHODS
  Observational, retrospective cohort study using Cox proportional hazards regression to determine effect of chemotherapy on hazard of all-cause mortality. The two samples were an overall sample (n=1,519) and a propensity score-matched sample (n=580) to control for selection to treatment receipt. Hazard ratios (HRs) and 95% confidence intervals (CIs) were obtained for regression models.
  
  
  METHODS
  U.S. women within the National Cancer Institute Surveillance, Epidemiology and End Results cancer registries (SEER) linked to Medicare enrollment and claims database.
  
  
  METHODS
  Female Medicare beneficiaries aged 66 and older with Stage IV ER- breast cancer diagnosed between 1999 and 2005.
  
  
  METHODS
  Outcome measure was all-cause death during the follow-up period. Survival was measured as time from breast cancer diagnosis until death or last follow-up date. Information on receipt of chemotherapy, defined as chemotherapy received within 6 months after diagnosis, was obtained from linked Medicare claims.
  
  
  RESULTS
  One thousand five hundred nineteen ER- women diagnosed with metastatic breast cancer were identified; 494 (33%) received chemotherapy. Chemotherapy was associated with a statistically significant survival benefit (HR=0.61, 95% CI=0.54-0.70). Age did not modify the survival benefit of chemotherapy.
  
  
  CONCLUSIONS
  Chemotherapy received within 6 months after diagnosis was associated with a 39% lower hazard of death within the time period for the study. These findings reflect chemotherapy use outside of the clinical trial setting and have important clinical and policy implications for the study of treatments in older women with advanced ER- breast cancer.
authors: School of Pharmacy, University of Maryland Baltimore, Maryland, USA.
authors: Myra
authors: M
authors: Schneider
authors: Ilene H
authors: IH
authors: Zuckerman
authors: Eberechukwu
authors: E
authors: Onukwugha
authors: Naimish
authors: N
authors: Pandya
authors: Brian
authors: B
authors: Seal
authors: Jim
authors: J
authors: Gardner
authors: C Daniel
authors: CD
authors: Mullins
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000097:blood; D001943:Breast Neoplasms / Q000188:drug therapy / Q000453:epidemiology* / Q000556:secondary; D002423:Cause of Death / Q000639:trends; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016016:Proportional Hazards Models; D011960:Receptors, Estrogen / Q000097:blood*; D012189:Retrospective Studies; D018426:SEER Program; D015996:Survival Rate / Q000639:trends; D014481:United States / Q000453:epidemiology
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen