title: Histological grading of papillary urothelial carcinoma of the bladder: prognostic value of the 1998 WHO/ISUP classification system and comparison with conventional grading systems.
abstract: OBJECTIVE
  To test the prognostic value of the 1998 WHO/ISUP (World Health Organisation/International Society of Urologic Pathology) consensus classification system in Ta papillary urothelial neoplasms of the bladder.
  
  
  METHODS
  The histological slides of 322 patients with a primary Ta tumour were classified according to the consensus classification system, and recurrence free survival (RFS) and progression free survival (PFS) were assessed for a mean follow up period of 79 months. In the same patient group, the RFS and PFS rates for the 1973 WHO grading system and a low grade/high grade system were analysed.
  
  
  RESULTS
  Recurrent tumours were seen in all categories of the 1998 WHO/ISUP classification system and five year RFS was not significantly different between the groups (p = 0.12). The five year PFS showed a small but significant difference (p = 0.04) between papillary neoplasms of low malignant potential (PNLMP) and high grade papillary urothelial carcinomas (HGPUCs). In the 1973 WHO classification, no significant difference was found in RFS and PFS between the different grades. In the low grade/high grade classification PFS was significantly better for low grade tumours (p = 0.01).
  
  
  CONCLUSIONS
  The prognostic value of the 1998 WHO/ISUP classification system is limited to predicting PFS, especially between PNLMP and HGPUC. The prognostic value of this system over other grading systems is questionable.
authors.affiliation: Department of Pathology, Stichting Ziekenhuizen Noord-Limburg, PO Box 1926, 5900 BX, Venlo, The Netherlands. j.w.a.oosterhuis@isala.nl
authors.forename: J W A
authors.initials: JW
authors.lastname: Oosterhuis
authors.forename: R F M
authors.initials: RF
authors.lastname: Schapers
authors.forename: M L G
authors.initials: ML
authors.lastname: Janssen-Heijnen
authors.forename: R P E
authors.initials: RP
authors.lastname: Pauwels
authors.forename: D W
authors.initials: DW
authors.lastname: Newling
authors.forename: F
authors.initials: F
authors.lastname: ten Kate
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002291:Carcinoma, Papillary / Q000473:pathology*; D002295:Carcinoma, Transitional Cell / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012008:Recurrence; D001749:Urinary Bladder Neoplasms / Q000473:pathology*