Prognostic impact of extraprostatic extension on prostate cancer with seminal vesicle invasion.

Objectives: Extraprostatic extension (EPE) and seminal vesicle invasion (SVI) are unfavorable factors for biochemical recurrence (BCR) following radical prostatectomy; however, some patients with SVI survive for a long duration without experiencing BCR after prostatectomy in absence of adjuvant therapy. This study aimed to clarify the heterogeneity of locally advanced prostate cancers to better understand prognosis in patients with SVI.

Methods: We retrospectively reviewed the medical records of 120 patients with SVI who underwent radical prostatectomy at two institutions. Multivariate logistic regression was used to evaluate the preoperative clinical and postoperative pathological variables as predictors of BCR. We also used Kaplan-Meier and competing risk regression analysis to assess the cumulative incidence and risk of BCR. After excluding patients who received neoadjuvant or adjuvant therapy, 55 patients with SVI were enrolled in this study.

Results: BCR occurred in 31 of these patients (56.3%). We found that Grade group and positive EPE were predictors of BCR in patients with SVI (P < 0.001 and P = 0.002, respectively). Using the multivariate model, EPE was significantly associated with BCR in patients with SVI (hazard ratio: 5.402; 95% confidence interval, 1.247-23.405; P = 0.012). Patients who were negative for EPE had significantly lower BCR rates (P = 0.002).

Conclusions: Among the patients with SVI tumors, prognosis might be different depending on presence or absence of EPE.