METHODS: From March 2000 to December 2013, 1777 patients underwent laparoscopic radical prostatectomy for localized prostate cancer. None received neoadjuvant or adjuvant therapy. One hundred and forty-six patients experienced BCR (range 3 months-10 years). Using D'Amico classification, 146 matched controls without BCR were compared. Liu cut-point analysis was used to identify TVP with optimal sensitivity and specificity. Single and composite BCR risk predictors were analyzed using Cox hazards regression in cases and controls.
RESULTS: Median TVP was 10% (range 1-90%). Most of BCR peaked after 3 years of follow-up. TVP ≥8% was an independent predictor of BCR with HR 1.6 (p= 0.001, 95% CI= 1.11-2.48). TVP of 8% was associated with the highest accuracy: sensitivity 74% and specificity 53% (ROC curve= 0.7). At TVP ≥8%, pathological stage pT3 was associated with 1.7-fold higher risk of BCR compared to T2. Lymph node invasion was associated with 1.4-fold higher risk of BCR compared to no invasion. Combining TVP ≥8%, pT3 and lymph node invasion, HR jumped to 3.73 (p< 0.001, 95% CI= 2.27-6.14), whereas combining TVP ≥8%, positive surgical margin and lymph node invasion, HR was 2.68 (p= 001, 95% CI= 1.50-4.77).
CONCLUSION: TVP can be used as an independent predictor of BCR after radical prostatectomy for prostate cancer. TVP cut-point of ≥8% allows the best discrimination. TVP should be considered in combination with other clinico-pathological factors to improve prediction of long-term oncological outcomes and to stratify BCR risk.