title: Persistent socioeconomic inequalities in cancer survival in the United States: 1973-2007 surveillance, epidemiology and end results (SEER) data for breast cancer and non-Hodgkin's lymphoma.
abstract: OBJECTIVE
  Census tract variables have not been widely available for SEER-wide data due to several technical reasons; thus, prior studies have been conducted on a specific-community basis only or used county-level data. This study is the first to evaluate long-term chronological trends in cancer survival by selected socioeconomic variables of census tract level based on multiple SEER registry data.
  
  
  METHODS
  177,128 breast cancer and 45,615 non-Hodgkin's lymphoma (NHL) cases diagnosed from 1973-2007 and followed through 2009 from 4 SEER registries (Detroit, Hawaii, Utah and Seattle-Puget Sound), were linked to decennial census tract data (1970-2000). Five-year relative survival was calculated using the lifetable method according to census tract poverty levels and by year of diagnosis. The Cox proportional hazard model was used to estimate hazard ratios (HR) for death in 5 years from diagnosis, adjusted for selected covariates and SEER historical stage in the limited models only.
  
  
  RESULTS
  Although the 5-year relative survival from both cancers improved similarly across poverty levels as percent per year, absolute increase per year was greater for lower poverty neighborhoods. This trend was most consistently observed for distant stage of cancer. The multivariable HR were significantly higher in the highest poverty group (greater than 20%), 1.41 and 1.33, for breast cancer and NHL respectively, than the lowest (greater than or equal to 5%). Additional adjustment for stage at diagnosis reduced the HR in the highest poverty level in breast cancer patients to 1.30, but had minimal effect on NHL. Socioeconomic disparities in overall survival were more evident in neighborhoods with higher proportions of racial minorities and in middle-aged patients than younger or older patients.
  
  
  CONCLUSIONS
  Relative survival for both types of cancer improved over last 35-year period across poverty levels, but absolute differences increased. More studies are needed to develop innovative community-level interventions.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Kato
authors.forename: Jason
authors.initials: J
authors.lastname: Booza
authors.forename: William O
authors.initials: WO
authors.lastname: Quarshie
authors.forename: Kendra
authors.initials: K
authors.lastname: Schwartz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000453:epidemiology / Q000401:mortality* / Q000628:therapy; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000453:epidemiology / Q000401:mortality* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology / Q000401:mortality*; D011159:Population Surveillance; D011203:Poverty / Q000706:statistics & numerical data*; D016016:Proportional Hazards Models; D018426:SEER Program / Q000706:statistics & numerical data; D012959:Socioeconomic Factors; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology