title: A multi-institutional study on histopathological characteristics of surgically treated renal tumors: the importance of tumor size.
abstract: OBJECTIVE
  The incidence of accidentally detected small renal tumors is increasing throughout the world. In this multi-institutional study performed in Korea, histopathological characteristics of contemporarily surgically removed renal tumors were reviewed with emphasis on tumor size.
  
  
  METHODS
  Between January 1995 and May 2005, 1,702 patients with a mean age of 55 years underwent surgical treatment at 14 training hospitals in Korea for radiologically suspected malignant renal tumors. Clinicopathological factors and patient survival were analyzed.
  
  
  RESULTS
  Of the 1,702 tumors, 91.7% were malignant and 8.3% were benign. The percentage of benign tumors was significantly greater among those < or = 4 cm (13.2%) than those > 4 cm (4.5%) (p < 0.001). Among renal cell carcinoma patients, the percentage of tumors classed as stage > or = T3 was significantly less among tumors < or = 4 cm (5.2%) than those > 4 cm (26.8%) (p < 0.001). The percentage of tumors classed as Fuhrman's nuclear grades > or = 3 was also significantly less among tumors < or = 4 cm (27.3%) than tumors > 4 cm (50.9%) (p < 0.001). The 5-year cancer-specific survival rate was 82.7%, and T stage (p < 0.001), N stage (p < 0.001), M stage (p = 0.025), and Fuhrman's nuclear (p < 0.001) grade were the only independent predictors of cancer-specific survival.
  
  
  CONCLUSIONS
  In renal tumors, small tumor size is prognostic for favorable postsurgical histopathologies such as benign tumors, low T stages, and low Fuhrman's nuclear grades. Our observations are expected to facilitate urologists to adopt function-preserving approach in the planning of surgery for small renal tumors with favorable predicted outcomes.
authors: Department of Urology, Ajou University School of Medicine, Suwon, Korea.
authors: Sun Il
authors: SI
authors: Kim
authors: Yeung Deuk
authors: YD
authors: Choi
authors: Se Joong
authors: SJ
authors: Kim
authors: Byung Ha
authors: BH
authors: Chung
authors: Do Hwan
authors: do H
authors: Seong
authors: Chun Il
authors: CI
authors: Kim
authors: Sang Hyeon
authors: SH
authors: Cheon
authors: Jin Seon
authors: JS
authors: Cho
authors: Yun Seob
authors: YS
authors: Song
authors: Young Sig
authors: YS
authors: Kim
authors: In Rae
authors: IR
authors: Cho
authors: Dong Hyeon
authors: DH
authors: Lee
authors: Ki Hak
authors: KH
authors: Song
authors: Hong Sup
authors: HS
authors: Kim
authors: Joong Shik
authors: JS
authors: Lee
authors: Won Jae
authors: WJ
authors: Yang
authors: Sung Joon
authors: SJ
authors: Hong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000145:classification / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging