Retrospective Cohort Analysis from a High-Volume Center of Prognostic Factors Affecting Biochemical Relapse in Patients with Encapsulated, Margin-Negative, Isolated Seminal Vesicle Invasion After Robot-Assisted Laparoscopic Prostatectomy: A Novel Study.

Purpose: Specimen pathology findings collectively impact the long-term outcomes of robot-assisted laparoscopic prostatectomy. Since seminal vesicle invasion (SVI) is an important independent predictor of biochemical recurrence (BCR), this study was designed to evaluate the influence of isolated SVI in the absence of capsular/margin invasion on BCR. Material and Methods: Pathology reports of 2009 robot-assisted laparoscopic prostatectomy specimens were analyzed retrospectively excluding capsular breach and/or margin-positive cases to include 1409 patients in the study. Factors predicting SVI and BCR in this select group of patients were assessed and statistically analyzed. Survival analysis for PSA (prostate-specific antigen) failure probability and binomial regressions for variable predictability were performed. Results: The African American race was associated with SVI (p < 0.05). PSA had a directly proportional correlation with the occurrence of SVI and BCR. SVI was found to be an independent predictor of BCR, leading to higher odds of BCR at 5 years (odds ratio [OR] 8.2, 95% confidence interval [CI] 4.5-14.6, p < 0.0001). When the seminal vesicle was invaded, the specimen Gleason grade group (SGGG; OR 1.9, 95% CI 1.02-3.7, p = 0.04), PSA (OR 1.2, 95% CI 1.01-1.4, p = 0.03), and BMI (body mass index) (OR 1.2, 95% CI 1.04-1.5, p = 0.01) predicted BCR. Seminal vesicle involvement was not found in SGGG 1. Risk stratification of significant predictors of BCR with isolated SVI identified a subgroup with BMI ≤27.9 kg/m2, PSA ≤8.6 ng/mL, and SGGG 2, which had a significantly better prognosis (p = 0.029, log-rank test). Conclusions: Seminal vesicles are infrequently involved with SGGG 1. Select groups of patients with isolated SVI who have low-grade disease with relatively lower PSA and BMI do not have an aggressive biological behavior and are unlikely to have a BCR, thereby circumventing unnecessary adjuvant therapy with its attendant side effects. The BMI significantly predicted PSA failures and should be considered as an additional risk assessment tool.