title: Geographic Variations of Colorectal and Breast Cancer Late-Stage Diagnosis and the Effects of Neighborhood-Level Factors.
abstract: The purpose of this study was to examine the geographic variations of late-stage diagnosis in colorectal cancer (CRC) and breast cancer as well as to investigate the effects of 3 neighborhood-level factors-socioeconomic deprivation, urban/rural residence, and spatial accessibility to health care-on the late-stage risks.
  
  
  
  This study used population-based South Dakota cancer registry data from 2001 to 2012. A total of 4,878 CRC cases and 6,418 breast cancer cases were included in the analyses. Two-level logistic regression models were used to analyze the risk of late-stage CRC and breast cancer.
  
  
  
  For CRC, there was a small geographic variation across census tracts in late-stage diagnosis, and residing in isolated small rural areas was significantly associated with late-stage risk. However, this association became nonsignificant after adjusting for census-tract level socioeconomic deprivation. Socioeconomic deprivation was an independent predictor of CRC late-stage risk, and it explained the elevated risk among American Indians. No relationship was found between spatial accessibility and CRC late-stage risk. For breast cancer, no geographic variation in the late-stage diagnosis was observed across census tracts, and none of the 3 neighborhood-level factors was significantly associated with late-stage risk.
  
  
  
  Results suggested that socioeconomic deprivation, rather than spatial accessibility, contributed to CRC late-stage risks in South Dakota as a rural state. CRC intervention programs could be developed to target isolated small rural areas, socioeconomically disadvantaged areas, as well as American Indians residing in these areas.
authors.affiliation: Department of Geography, South Dakota State University, Brookings, South Dakota.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Geospatial Sciences Center of Excellence, South Dakota State University, Brookings, South Dakota.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Wimberly
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D057210:Delayed Diagnosis / Q000706:statistics & numerical data*; D005260:Female; D006297:Health Services Accessibility / Q000592:standards*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012042:Registries / Q000706:statistics & numerical data; D012959:Socioeconomic Factors; D013023:South Dakota / Q000453:epidemiology
keywords: breast cancer; colorectal cancer; geographic access to care; health disparities; rural