Biopsy and implantation of the seminal vesicles

To describe the technique and outcomes of seminal vesicle biopsy (SVB) and permanent implantation in patients with T3b prostate cancer.

Intermediate- and high-risk prostate cancer patients who elected brachytherapy as their treatment of choice were offered SVB for either Gleason score ≥7, prostate-specific antigen levels >10ng/mL, or clinical stage ≥T2b. Three cores were taken from both seminal vesicles at the base of the prostate using transrectal ultrasound. Patients with a positive SVB and either a negative pelvic lymph node dissection or pelvic computerized tomogram were treated with a combination of a partial implant followed by 45Gy of external beam irradiation therapy. During the seed implant, sources were positioned in the anterior wall of the seminal vesicles using intraoperative dosimetry to guide placement. Biochemical freedom from failure was determined using a definition of >0.2ng/mL. Survival was measured using the Kaplan-Meier and Cox proportions projections.

Of 526 patients who underwent SVB, 52 (9.9%) were positive for prostate cancer invasion. Clinical stage, prostate-specific antigen levels, and Gleason score were all predictive of a positive SVB (p<0.001). The 10-year biochemical freedom from failure was 64%. Cox regression demonstrated Gleason score (p=0.044) and biologic effective dose (p=0.013) as significant.

Patients with pathologically confirmed seminal vesicle involvement of prostate cancer can be successfully identified and managed by a combined approach of permanent seed implantation to the prostate and seminal vesicles followed by external beam irradiation therapy. SVB should be encouraged in men with high-risk prostate cancer and aggressively treated when encountered.