title: Racial disparity in colorectal cancer: the role of ABO blood group.
abstract: BACKGROUND
  We tested the hypothesis that racial differences that exist in the distribution of ABO blood type would partially explain the racial disparity in overall survival seen in colorectal cancer.
  
  
  METHODS
  retrospective analysis of the cancer registry of a university hospital for patients treated for colorectal cancer between 1996 and 2008. Demographic, tumor-specific, and treatment-specific variables were abstracted. We also obtained ABO blood group data. The primary end point was overall survival. We divided patients into two groups based on where they underwent surgery: the University of Arkansas for Medical Sciences (UAMS) or outside facilities.
  
  
  RESULTS
  Of 833 patients, 182 (21.8%) were black. There was no difference in overall survival between blacks and whites for the entire group (P = 0.61). There was a statistically significant difference in overall survival between patients at the UAMS and outside facilities (P < 0.0001). For the outside facilities group, there was a statistically significant difference in overall survival between blacks and whites (hazard ratio, CI: 1.48 [1.06-2.00]; P = 0.012); no race difference existed for the UAMS group. The ABO blood group had no effect on overall survival. On stage-stratified univariate and multivariate analyses, chemotherapy and surgery were the only statistically significant determinants of survival.
  
  
  CONCLUSIONS
  In this study, racial differences in ABO blood group distribution had no effect on overall survival.
authors.affiliation: Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA. jalaryea@uams.edu
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Laryea
authors.forename: Eric
authors.initials: E
authors.lastname: Siegel
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Burford
authors.forename: Suzanne V
authors.initials: SV
authors.lastname: Klimberg
mesh_terms: D000017:ABO Blood-Group System; D000046:Academic Medical Centers / Q000706:statistics & numerical data; D000368:Aged; D001131:Arkansas / Q000453:epidemiology; D015179:Colorectal Neoplasms / Q000208:ethnology* / Q000401:mortality / Q000628:therapy; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012042:Registries; D012189:Retrospective Studies
chemical_list: D000017:ABO Blood-Group System