Prognostic Significance of the Tumor Volume and Tumor Percentage for Localized Prostate Cancer

Chung, Jae Seung; Han, Byoung Kyu; Jeong, Seong Jin; Hong, Sung Kyu; Byun, Seok Soo; Choe, Gheeyoung; Lee, Sang Eun

Abstract

PURPOSE: Tumor volume has been thought to be an important predictive factor for significant prostate cancer. We assessed the impact of the tumor volume(TV) and the tumor percentage(TP) of radical prostatectomy specimens on the pathological variables and the oncological outcome. MARERIALS AND METHODS: The tumor percentage and tumor volume were calculated for 525 cases by a single pathologist who determined the volume based on the surface area of the slides involved by tumor of the prostate. Univariate and multivariate logistic regression analyses were used to characterize the association of TP categories(<5%, 5-10%, 11-20% and >20%) and TV(<1.8cc, 1.8-3.7cc, 3.8-7.5cc, >7.5cc) with the clinicopathological variables. Biochemical recurrence(BCR) was estimated using Kaplan-Meier analysis and Cox's hazard regression model.
RESULTS
The mean prostate cancer volume was 6.5+/-8.5cc(median: 3.8, range: 0.04-73.8) and the mean percent tumor composition was 0.17+/-0.19 (median: 0.1, range: 0.01-0.95). A higher tumor volume and a higher tumor percentage were associated with extra-capsular extension(ECE), a positive surgical margin(PSM), a higher pT stage and a higher prostate-specific antigen(PSA) Gleason score(all p<0.05). In addition, TP was the independent predictor of ECE(adjusted odds ratio(OR): 22.66, 95% confidence interval(CI): 1.801-285.079, p=0.016), but the tumor volume was not associated with ECE on the multivariate logistic analyses. On the Kaplan-Meier analysis, but not on the Cox-hazard analyses, the TP did demonstrate a significant association with biochemical recurrence(p=0.035), yet the TV did not reach statistical significance(p=0.190).
CONCLUSIONS
Our data indicates that the tumor percentage had a significant effect on the BCR on the Kaplan-Meier analysis. The tumor percentage rather than the tumor volume might be more useful to predict the prognosis of prostate cancer.