title: Use of the Gleason system in international comparisons of prostatic adenocarcinomas in blacks.
abstract: BACKGROUND
  Comparisons of prostate cancer in blacks living in different countries can shed light on factors responsible for high rates of the disease among blacks in America. Since the prognostic value of the Gleason grading system is well established, we assessed agreement between pathologists in countries where black populations of the African Diaspora reside.
  
  
  METHODS
  Three genitourinary pathologists at hospitals in Nigeria, Jamaica, and the US independently assessed sextant biopsies from 12 patients. Gleason sum and percentage involvement were recorded, and a percent-weighted average calculated. Agreement under different groupings was evaluated using the kappa statistic generalized to three raters.
  
  
  RESULTS
  Agreement was significant for individual sums (kappa = 0.3317, P = 0.0173), sums grouped as well (2-4), moderately (5-6), and poorly differentiated (7-10) (kappa = 0.2437, P < 0.0001) and other groupings. Agreement between at least two raters was 91.7-100%; complete agreement was 41.7-66.7%.
  
  
  CONCLUSIONS
  The Gleason system is feasible and practical for international studies of prostate cancer among blacks from contrasting environments.
authors.affiliation: Department of Medicine, Stritch School of Medicine, Loyola University Medical Center, Maywood, Illinois, USA. Freeman@research.hines.med.va.gov
authors.forename: Vincent L
authors.initials: VL
authors.lastname: Freeman
authors.forename: Kathleen C M
authors.initials: KC
authors.lastname: Coard
authors.forename: Eva
authors.initials: E
authors.lastname: Wojcik
authors.forename: Ramon
authors.initials: R
authors.lastname: Durazo-Arvizu
mesh_terms: D000230:Adenocarcinoma / Q000145:classification / Q000208:ethnology* / Q000473:pathology*; D001706:Biopsy; D044383:Black People; D002454:Cell Differentiation; D006801:Humans; D007391:International Cooperation; D008297:Male; D009367:Neoplasm Staging / Q000379:methods*; D015588:Observer Variation; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000145:classification / Q000208:ethnology* / Q000473:pathology*; D015203:Reproducibility of Results