Clinical and pathologic tumor size in renal cell carcinoma; difference, correlation, and analysis of the influencing factors.

OBJECTIVES: To investigate the relation between the clinical and pathologic size and to identify the factors that affect this relationship. The clinical size of the tumor is essential for choosing the appropriate treatment in renal cell carcinoma. The pathologic size, on the other hand, is an important prognostic indicator.
METHODS: We reviewed the charts of 291 open nephrectomy patients treated for nonmetastatic renal cell carcinoma. Clinical size was defined as the largest diameter on contrast-enhanced computed tomography. Pathologic size was defined as the largest diameter on pathologic examination. The clinical and pathologic sizes were compared, and their correlation was analyzed. The effect of various clinical and pathologic factors on the percentage of the size difference (%Delta(size)) was analyzed.
RESULTS: The mean clinical and pathologic size was 5.4 +/- 3.2 and 5.3 +/- 3.3 cm, respectively. The difference was not significant (P = 0.1679). The clinical and pathologic size also correlated highly (r = 0.9540; P <0.0001). The estimated blood loss, local tumor extension, and cell type had significant influence on the %Delta(size) (P = 0.0018, 0.0415, and 0.0079, respectively). Additionally, in approximately one half of the patients with the greatest size difference, features such as cystic masses, hemorrhage, pyelonephritis, localization near or invasion of the collecting system, cysts or dilated calices adjacent to the tumor, and multiple cysts within the kidney were present, which were identified as factors that might have influenced the accuracy of the clinical size.
CONCLUSIONS: The overall accuracy of the clinical size and its correlation with the pathologic size was acceptable. However, the presence of the above-mentioned factors should be taken into consideration during the interpretation of clinical tumor size.