Complete resection of seminal vesicles at radical prostatectomy results in substantial long-term disease-free survival: multi-institutional study of 6740 patients.

OBJECTIVES: To estimate the disease-specific survival of patients with complete removal of the seminal vesicles (SVs) at radical prostatectomy and to develop a nomogram for the prediction of SV invasion (SVI).
METHODS: An analysis of 6740 patients from three institutions was performed. The primary outcome was biochemical failure analyzed according to the presence or absence of SVI using the Kaplan-Meier method and Cox proportional hazards model. The variables analyzed included age, biopsy Gleason score, clinical T stage, margin status, extracapsular extension, SVI, surgical Gleason score, initial prostate-specific antigen level, and institution. Logistic regression analysis was used to determine the preoperative factors predicting for SVI and create the model for the nomogram.
RESULTS: Of the 6740 patients, 566 (8.4%) had positive SVs. The median follow-up was 33.4 months (range 1 to 239). The 5 and 10-year biochemical relapse-free survival rate was 38.0% and 25.6%, respectively, for patients with positive SVs and 85.7% and 77.2%, respectively, for patients with negative SVs (P <0.0001). In the multivariate model, all variables, except for biopsy Gleason score and T stage, were significant predictors of biochemical failure (P <0.05), and all variables, except for age, were predictors of SVI. The nomogram achieved an area under the curve of 0.80.
CONCLUSIONS: These results have demonstrated that a substantial number of patients with SVI are disease free at 5 and 10 years after complete excision without adjuvant therapy. These findings suggest the therapeutic efficacy of complete SV excision and can identify those with a nomogram-predicted increased risk of SVI who might benefit from complete excision.