title: Reclassification of patients with pT3 and pT4 renal cell carcinoma improves prognostic accuracy.
abstract: BACKGROUND
  The significance of adrenal invasion and tumor thrombus in renal cell carcinoma (RCC) has been debated recently. The authors evaluated the associations of direct adrenal invasion, perinephric fat invasion, and tumor thrombus level with outcome to determine whether reclassification would improve the prognostic accuracy of the current primary tumor classification.
  
  
  METHODS
  The authors studied 697 patients treated with nephrectomy for pT3 and pT4 RCC between 1970 and 2000. Associations with outcome were evaluated using Cox proportional hazards regression and prognostic accuracy was measured using the c index.
  
  
  RESULTS
  Among patients with pT3 RCC, direct adrenal invasion was significantly associated with death from RCC (risk ratio, 2.11; P = 0.004). No significant difference in survival was found between patients with pT4 RCC and pT3 tumors with direct adrenal invasion (P = 0.490). Among patients with pT3b RCC, those with level I-III tumor thrombus were significantly more likely to die of RCC compared with patients harboring level 0 tumor thrombus (risk ratio, 1.62; P < 0.001). In addition, patients with fat invasion were more likely to die of RCC compared with pT3 patients without fat invasion (risk ratio, 1.87; P < 0.001). Therefore, patients with pT3 RCC were reclassified into 4 prognostic groups, and this reclassification significantly improved prediction of death from RCC compared with the current classification (c indices of 0.61 vs. 0.55, respectively).
  
  
  CONCLUSIONS
  Direct adrenal invasion from RCC should be reclassified as pT4. In addition, the proposed reclassification for patients with pT3 RCC improved prognostic accuracy.
authors.affiliation: Department of Urology, Mayo Medical School and Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: R Houston
authors.initials: RH
authors.lastname: Thompson
authors.forename: John C
authors.initials: JC
authors.lastname: Cheville
authors.forename: Christine M
authors.initials: CM
authors.lastname: Lohse
authors.forename: W Scott
authors.initials: WS
authors.lastname: Webster
authors.forename: Horst
authors.initials: H
authors.lastname: Zincke
authors.forename: Eugene D
authors.initials: ED
authors.lastname: Kwon
authors.forename: Igor
authors.initials: I
authors.lastname: Frank
authors.forename: Michael L
authors.initials: ML
authors.lastname: Blute
authors.forename: Bradley C
authors.initials: BC
authors.lastname: Leibovich
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000401:mortality / Q000556:secondary; D002292:Carcinoma, Renal Cell / Q000145:classification / Q000401:mortality / Q000473:pathology*; D006801:Humans; D007680:Kidney Neoplasms / Q000145:classification / Q000401:mortality / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging / Q000379:methods*; D016609:Neoplasms, Second Primary / Q000401:mortality; D011379:Prognosis; D016016:Proportional Hazards Models; D016019:Survival Analysis; D015996:Survival Rate