title: Assessment of stage T1 (TNM 1997) for renal cell carcinoma: is recommended the subdivision in T1a and T1b?
abstract: BACKGROUND
  Classification TNM 1997 defines renal cell carcinoma smaller than 7 cm and confined to the kidney as stage T1. Our goal is to discuss if tumors smaller than 4 cm have the same behavior characteristics then tumors between 4 and 7 cm, to compose the same stage of the disease.
  
  
  METHODS
  Retrospective assessment of 138 patients in stage T1 (TNM - 97), divided into 2 groups; group-1: composed of 65 patients (47%) with tumors < 4 cm, and group-2: composed of 73 patients (53%) with tumors between 4 and 7 cm. The following prognostic factors were assessed in the recurrence of the disease and survival of patients: nuclear degree, microvascular invasion, sarcomatous degeneration, and involved lymph nodes. Statistical evaluation has been accomplished through the log rank test, chi-square test, and Fisher's exact text.
  
  
  RESULTS
  Average tumor size was 2.5 cm for group-1, and 5.3 cm for group-2. In group-2, there was the predominance of worse prognostic factors, with high-grade tumors (p = 0.01) and presence of microvascular invasion (p = 0.001). Sarcomatous tumors and involvement of lymph nodes did only happen in group-2. Disease-free survival for group-1, analyzed in the median period of 36 months, was 100%, and for group 2, in the median period of 31 months, was 81% (p = 0.008).
  
  
  CONCLUSIONS
  The results obtained allow the conclusion that the present stage T1 for renal cell carcinoma gathers tumors of different evolution, being therefore recommendable the stratification in T1a for tumors smaller than 4 cm, and T1b for tumors between 4 and 7 cm.
authors.affiliation: Divisions of Urology and Statistics, Paulista School of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil.
authors.forename: Marcos
authors.initials: M
authors.lastname: Dall'Oglio
authors.forename: Miguel
authors.initials: M
authors.lastname: Srougi
authors.forename: Marcelo
authors.initials: M
authors.lastname: Mangini
authors.forename: Eduardo
authors.initials: E
authors.lastname: Ribeiro
authors.forename: Márcio
authors.initials: M
authors.lastname: Ferraz
authors.forename: Adriana
authors.initials: A
authors.lastname: Sañudo
authors.forename: Kátia
authors.initials: K
authors.lastname: Leite
authors.forename: Luciano
authors.initials: L
authors.lastname: Nesrallah