The impact of three-dimensional tumor volume on cancer-specific survival for patients with pT1 clear-cell renal cell carcinoma.
To evaluate the impact of three-dimensional tumor volume on cancer-specific survival for patients with pT1 clear-cell renal cell carcinoma (ccRCC). We reviewed a prospectively maintained database of 917 patients who underwent radical nephrectomy or nephron-sparing surgery for unilateral, pT1 ccRCC, including 654 pT1a and 263 pT1b patients, between April 1997 and December 2010. Three-dimensional tumor volume was measured using specialized volumetric software on cross-sectional computed tomography images of a preoperative venous phase. Kaplan-Meier and Cox regression analyses were carried out. The median age was 54 years with a follow-up of 60.8 months. Median tumor size and volume were 3.2 cm and 17.4 cm(3), respectively. Of 917 patients, 54 (5.9 %) had died, including 32 patients with ccRCC (9 patients in pT1a and 23 patients in pT1b). On multivariate analysis, tumor size >3.2 cm and tumor volume >17.4 cm(3) were associated with cancer-specific death in pT1 ccRCC patients. When stratified by pT1a/pT1b status and analyzed on median splits, tumor size >2.5 cm was associated with cancer-specific death but not tumor volume >9.5 cm(3) in pT1a patients. However, in pT1b patients, tumor volume >62.1 cm(3) (P = 0.036, HR 2.91, 95 % CI 1.02-7.77) was highly associated with cancer-specific death but not tumor size >5.0 cm (P = 0.159, HR 1.91, 95 % CI 0.78-4.70). In addition to tumor size, tumor volume is associated with cancer-specific death in pT1 ccRCC patients, particularly in pT1b ccRCC but not in pT1a ccRCC.