title: Effectiveness of adjuvant chemotherapy for node-positive operable breast cancer in older women.
abstract: BACKGROUND
  Randomized clinical trials have shown the efficacy of adjuvant chemotherapy in treating node-positive operable breast cancer in women aged < or = 69 years, but the benefit of chemotherapy in women aged > or = 70 is questionable. This study was to examine if adjuvant chemotherapy is effective for these women with breast cancer.
  
  
  METHODS
  We studied a cohort of 5464 women diagnosed with node-positive operable breast cancer at age > or = 65 in 1992 through 1996 with last follow-up of December 31, 1999 in five states and six metropolitan areas. Hazard ratio (HR) for all-cause mortality was used for survival analysis with adjustment for patient and tumor characteristics; propensity analysis was used to control for observed factors; and sensitivity analysis was used to estimate potential effects of unmeasured confounders.
  
  
  RESULTS
  After adjusting for propensity to receive chemotherapy, the chemotherapy-treated and untreated groups were not statistically significantly different for covariates except for age and hormone receptor status. Mortality was significantly reduced in women aged 65-69 who received adjuvant chemotherapy compared to those who did not, after adjusting for patient and tumor characteristics (HR = 0.70, 95% confidence interval [CI], 0.57-0.88) or after adjusting for propensity scores (HR = 0.76, 95% CI, 0.62-0.94). HR did not significantly differ between the treated and untreated women aged > or = 70 (HR = 0.96, 95% CI = 0.83-1.09, and HR = 0.99, 95% CI, 0.87-1.14). These results were relatively insensitive to changes in unmeasured confounders.
  
  
  CONCLUSIONS
  Adjuvant chemotherapy is associated with improved survival in women with node-positive operable breast cancer aged 65-69 living in the community, but not in women aged > or = 70. These findings are consistent with those found in randomized controlled trials.
authors.affiliation: School of Public Health, University of Texas Health Science Center at Houston, 1200 Herman Pressler Drive, RAS-E631, Houston, TX 77030, USA. xdu@sph.uth.tmc.edu
authors.forename: Xianglin L
authors.initials: XL
authors.lastname: Du
authors.forename: Dennie V
authors.initials: DV
authors.lastname: Jones
authors.forename: Dong
authors.initials: D
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000601:surgery*; D017024:Chemotherapy, Adjuvant; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008408:Mastectomy; D008875:Middle Aged; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology
chemical_list: D000970:Antineoplastic Agents