Tumor volume improves the long-term prediction of biochemical recurrence-free survival after radical prostatectomy for localized prostate cancer with positive surgical margins.

PURPOSE

To develop a novel application evaluating the effect of tumor volume (TV) and percentage of high-grade tumor volume (%HGTV) on long-term biochemical recurrence-free survival rate (BCRFS) after radical prostatectomy (RP) in patients with pT2 PCa.

METHODS

Retrospective analysis of 903 men with pT2 PCa between 1992 and 2004 at a single European tertiary care center was performed. Cox regression models identified risk factors for BCR. A nomogram was developed to predict the BCRFS at 5, 10 and 15 years after RP. Decision curve analyses were performed to identify the net increase in cases identified by the full model.

RESULTS

BCR-free survival rates at 5, 10 and 15 years were 94, 90 and 86 %. In Cox regression analyses, TV, %HGTV and positive surgical margin status (SM) were independent predictors of BCR. Predictive accuracies (PA) at 5, 10 and 15 years of the base model (PSA, Gleason score, SM) were 76.8 % (95 % CI 67.9-78.2 %), 70.5 % (95 % CI 64.9-75.0 %) and 68.1 % (95 % CI 60.6-73.5 %). The full model, including TV and %HGTV, achieved 76.9, 72.4 and 70.7 %. These PA differences were statistically significant at 10 and 15 years (p < 0.001).

CONCLUSIONS

TV and %HGTV could potentially serve as valuable measures to stratify patients at high risk of BCR. The use of our nomogram should be considered to counsel patients with pT2 disease and SM and to design appropriate follow-up or treatment regimens.