title: The value of histologic subtyping on outcomes of clear cell and papillary renal cell carcinomas: a meta-analysis.
abstract: OBJECTIVE
  To investigate the survival differences among clear cell renal cell carcinoma (RCC) and type 1 and type 2 papillary RCCs by means of a meta-analysis.
  
  
  METHODS
  We combined data from studies published between 1997 and 2009. The effect sizes of overall survival were estimated by unadjusted or adjusted hazard ratio. Survival rates between clear cell RCC and nonclear cell RCC were compared by uni- and multivariate analyses of 3 studies including 2169 and 2455 patients, respectively. Survival outcomes between clear cell RCC and papillary RCC were compared by uni- and multivariate analyses of 17 studies involving 21,856 patients and 3 studies involving 3112 patients, respectively. Survival rates between type 1 and type 2 papillary RCCs were compared by uni- and multivariate analyses of 8 studies involving 634 patients and 5 studies involving 438 patients, respectively.
  
  
  RESULTS
  Patients with clear cell RCC had poorer survival than patients with nonclear cell type in univariate analysis (hazard ratio, 2.02; P < .001). The overall survival of patients with clear cell RCC was not different from that of patients with papillary RCC in uni- and multivariate analyses. Patients with type 2 papillary RCC had a poorer outcome than patients with type 1 papillary RCC in uni- and multivariate analyses (hazard ratios, 2.91 and 1.80; P < .001 and P = .044, respectively).
  
  
  CONCLUSIONS
  Meta-analysis confirms that clear cell RCC and papillary RCC are not different in survival outcomes. In addition, type 2 papillary RCC shows poorer survival than type 1 papillary RCC.
authors.affiliation: Department of Pathology, Korea University, Ansan Hospital, Ansan, Republic of Korea.
authors.forename: Ju-Han
authors.initials: JH
authors.lastname: Lee
authors.forename: Jung-Woo
authors.initials: JW
authors.lastname: Choi
authors.forename: Young-Sik
authors.initials: YS
authors.lastname: Kim
mesh_terms: D002292:Carcinoma, Renal Cell / Q000145:classification / Q000401:mortality / Q000473:pathology*; D003625:Data Collection; D006801:Humans; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000145:classification / Q000401:mortality / Q000473:pathology*; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D015996:Survival Rate; D016896:Treatment Outcome