title: The Prognostic Factors for Patients with pT1a Renal Cell Carcinoma.
abstract: OBJECTIVE
  Although the prognosis of patients with pT1a stage renal cell carcinoma (RCC) is generally good, some of these patients show distant metastasis. In this study, we intended to identify the perioperative and pathologic prognostic factors for patients with pT1a stage RCC.
  
  
  METHODS
  A total of 93 patients who were diagnosed with pT1aN0M0 RCC between January 1995 and December 2004 were included. All the patients underwent radical (n=63, 67.7%) or partial (n=30, 32.3%) nephrectomy by a single surgeon. Preoperative data [age, sex, body mass index (BMI), and the presence of symptoms], follow-up duration, surgical methods, and pathological parameters (tumor size, tumor location, histologic type, Fuhrman's nuclear grade and the presence of microvascular invasion, hemorrhage, necrosis, calcification, and a cystic component in the tumor) were retrospectively analyzed to identify which of these were prognostic factors for pT1a RCC.
  
  
  RESULTS
  The patients' mean age was 55.0+/-11.4 years and the mean follow-up duration was 63.6+/-31.1 months. The 5-year cancer-specific survival rate and the 5-year recurrence- free survival rate were 100% and 88.1%, respectively. Nine patients (9.7%) showed distant metastasis, but local recurrence was not shown. Fuhrman's nuclear grade (p=0.040, OR=5.147), microvascular invasion (p=0.011, OR=13.500), and tumor necrosis (p<0.001, OR=26.000) had a significant impact on distant metastasis in the univariate analysis. The multivariate analysis subsequently showed that microvascular invasion (p=0.033, OR=17.947) and tumor necrosis (p=0.002, OR=15.922) were independent prognostic factors.
  
  
  CONCLUSIONS
  Microvascular invasion and tumor necrosis are the prognostic factors for patients with pT1a RCC.
authors.affiliation: Department of Urology, College of Medicine, Yeungnam University, Daegu, Korea.
authors.forename: Jong Min
authors.initials: JM
authors.lastname: Kim
authors.forename: Phil Hyun
authors.initials: PH
authors.lastname: Song
authors.forename: Hyun Tae
authors.initials: HT
authors.lastname: Kim
authors.forename: Tong Choon
authors.initials: TC
authors.lastname: Park