title: Survival following the diagnosis of noninvasive bladder cancer: WHO/International Society of Urological Pathology versus WHO classification systems.
abstract: OBJECTIVE
  The WHO/International Society of Urological Pathology classification of bladder cancer, introduced in 1998, differs from the traditional 1973 WHO classification. Few studies have reported survival data based on the WHO/International Society of Urological Pathology classification and none has demonstrated clear superiority compared to the 1973 WHO system. In a large, nonselected population of patients with bladder cancer we rated all incident tumors using each system and compared long-term patient survival.
  
  
  METHODS
  New Hampshire residents with bladder cancer diagnosed between 1994 and 2000 were identified through the State Cancer Registry. Slides were retrieved from more than 90% of cases and reviewed by a single pathologist. Tumors were classified according to WHO and WHO/International Society of Urological Pathology criteria. Overall patient survival was determined for the cohort of 504 patients after an average of 7 years using a national mortality database.
  
  
  RESULTS
  For both grading systems there was a gradient of progressively lower survival times from the lowest grade to the highest grade tumors. Hazard ratios and 95% confidence intervals for the WHO/International Society of Urological Pathology system were 1.9 (1.0-3.4) for low grade papillary urothelial carcinoma and 3.0 (1.5-6.0) for high grade papillary urothelial carcinoma, compared to papillary urothelial neoplasms of low malignant potential. For the WHO (1973) system compared to grade 1 tumors the hazard ratio for grade 2 tumors was 1.8 (1.1-3.1) and for grade 3 was 2.4 (1.2-4.7).
  
  
  CONCLUSIONS
  Advantages of the WHO/International Society of Urological Pathology bladder tumor classification include more detailed diagnostic criteria, the ability to define a lesion with minimal malignant potential and the ability to identify a larger group of patients needing closer surveillance. However, we found that the WHO/International Society of Urological Pathology tumor categories did not detect a clear overall survival advantage compared to the WHO (1973) classification system.
authors: Department of Pathology, Dartmouth Medical School, Lebanon, New Hampshire 03756, USA. alan.schned@hitchcock.org
authors: Alan R
authors: AR
authors: Schned
authors: Angeline S
authors: AS
authors: Andrew
authors: Carmen J
authors: CJ
authors: Marsit
authors: M Scot
authors: MS
authors: Zens
authors: Karl T
authors: KT
authors: Kelsey
authors: Margaret R
authors: MR
authors: Karagas
mesh_terms: D000368:Aged; D002295:Carcinoma, Transitional Cell / Q000175:diagnosis / Q000401:mortality / Q000473:pathology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009513:New Hampshire; D011379:Prognosis; D016016:Proportional Hazards Models; D012042:Registries; D016019:Survival Analysis; D001743:Urinary Bladder / Q000473:pathology; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000473:pathology*