A multi-institutional study on histopathological characteristics of surgically treated renal tumors: the importance of tumor size.
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.
Kim
Sun Il
SI
Department of Urology, Ajou University School of Medicine, Suwon, Korea.
Choi
Yeung Deuk
YD
Kim
Se Joong
SJ
Chung
Byung Ha
BH
Seong
Do Hwan
do H
Kim
Chun Il
CI
Cheon
Sang Hyeon
SH
Cho
Jin Seon
JS
Song
Yun Seob
YS
Kim
Young Sig
YS
Cho
In Rae
IR
Lee
Dong Hyeon
DH
Song
Ki Hak
KH
Kim
Hong Sup
HS
Lee
Joong Shik
JS
Yang
Won Jae
WJ
Hong
Sung Joon
SJ
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