title: Improvements in US Breast Cancer Survival and Proportion Explained by Tumor Size and Estrogen-Receptor Status.
abstract: OBJECTIVE
  Breast cancer mortality began declining in many Western countries during the late 1980s. We estimated the proportion of improvements in stage- and age-specific breast cancer survival in the United States explained by tumor size or estrogen receptor (ER) status.
  
  
  METHODS
  We estimated hazard ratios for breast cancer-specific death from time of invasive breast cancer diagnosis in the National Cancer Institute's Surveillance, Epidemiology, and End Results 9 Registries Database from 1973 to 2010, with and without stratification by tumor size and ER status.
  
  
  RESULTS
  Hazards from breast cancer-specific death declined from 1973 to 2010, not only in the first 5 years after diagnosis, but also thereafter. Stratification by tumor size explained less than 17% of the improvements comparing 2005 to 2010 versus 1973 to 1979, except for women age ≥ 70 years with local (49%) or regional (38%) disease. Tumor size usually accounted for more of the improvement in the first 5 years after diagnosis than later. Additional adjustment for ER status (positive, negative, or unknown) from 1990 to 2010 did not explain much more of the improvement, except for women age ≥ 70 years within 5 years after diagnosis.
  
  
  CONCLUSIONS
  Most stage-specific survival improvement in women younger than age 70 years old is unexplained by tumor size and ER status, suggesting a key role for treatment. In the first 5 years after diagnosis, tumor size contributed importantly for women ≥ 70 years old with local and regional stage, and stratification by tumor size and ER status explained even more of the survival improvement among women age ≥ 70 years.
authors.affiliation: Ju-Hyun Park, Dongguk University, Seoul, South Korea; and William F. Anderson and Mitchell H. Gail, National Cancer Institute, Bethesda, MD.
authors.forename: Ju-Hyun
authors.initials: JH
authors.lastname: Park
authors.affiliation: Ju-Hyun Park, Dongguk University, Seoul, South Korea; and William F. Anderson and Mitchell H. Gail, National Cancer Institute, Bethesda, MD.
authors.forename: William F
authors.initials: WF
authors.lastname: Anderson
authors.affiliation: Ju-Hyun Park, Dongguk University, Seoul, South Korea; and William F. Anderson and Mitchell H. Gail, National Cancer Institute, Bethesda, MD. gailm@mail.nih.gov.
authors.forename: Mitchell H
authors.initials: MH
authors.lastname: Gail
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000737:chemistry / Q000401:mortality* / Q000473:pathology; D005260:Female; D006801:Humans; D008875:Middle Aged; D011960:Receptors, Estrogen / Q000032:analysis*; D018426:SEER Program
chemical_list: D011960:Receptors, Estrogen