Seminal vesicle biopsy and laparoscopic pelvic lymph node dissection: implications for patient selection in the radiotherapeutic management of prostate cancer

Purpose : Seminal vesicle biopsies (SVB) and laparoscopic pelvic lymph node dissection (LPLND) are safe surgical staging procedures for prostate cancer that can yield more accurate information than can be obtained by routine clinical means. This information is critical in patient and treatment selection when planning definitive prostate irradiation. An analysis of the procedural findings was undertaken to better define those patients who might benefit from these procedures. Methods and Materials : From June 1990 to February 1994, 120 patients with clinical Stage Tlb to T2c prostate cancer with negative bone scan and pelvic computerized tomography (CT) scans underwent transrectal ultrasound guided SVB (three from each side). Of these patients, 99 also underwent LPLND. Twelve patients were excluded from analysis of LPLND findings because they were treated with 3 months of hormonal therapy prior to LPLND. During LPLND, 0 to 18 nodes were removed (median-five nodes) from the right side and 0 to 20 nodes (median-five nodes) were removed from the left side. Prostate specific antigen (PSA) values ranged from 1.6 to 190 ng/ml, with a median value of 11.5. Combined Gleason grades ranged from 2 to 9, with a median of 6. Results : A positive SVB was found in 18 patients (15%). A logistic regression analysis was performed to test the effect of grade, PSA, and stage on SVB results. Combined grade and PSA were significant predictors of a positive SVB (p <0.001 and p = 0.024, respectively). Patients with combined grades of 7 or greater had a higher positive SVB rate of 37.5% (12 out of 32) compared to 7% (6 out of 88) for patients with a lower grade (p <0.0001). Patients with PSA values greater than 10 had a positive SVB rate of 21% (15 out of 70) compared to 6% (3 out of 50) for patients with values up to 10. There was no morbidity associated with SVB. Laparoscopic pelvic lymph node disection detected positive pelvic nodes in nine patients (10%). The effect of a positive SVB, combined Gleason grade, PSA, and stage on the detection of positive nodes were tested using a stepwise logistic regression analysis. Seminal vesicle biopsy was the most significant predictor of positive nodes (p <0.0001), while combined grade and PSA were also significant predictors (p = 0.0006 and p = 0.005, respectively). Positive nodes were found in 50% (9 out of 18) of patients with positive SVB compared to 0% (0 out of 69) of patients with a negative SVB (p <0.0001). Positive nodes were found in 35% (8 out of 23) of patients with a combined grade of 7 or greater compared to 2% (1 out of 64) of patients with a combined grade less than 7 (p <0.0001). Laparoscopic pelvic lymph node dissection revealed positive nodes in 3% (2 out of 58) of patients with PSA levels < = 20 compared to 24% (7 out of 29) of patients with PSA levels greater than 20 (p = 0.003). Laparoscopic pelvic lymph node dissection was associated with a hospital stay of one night and a minor complication rate of 4%. There were no major complications. Conclusions : Seminal vesicle biopsy should be performed before treatment in all patients, except those with low risk factors, undergoing radiation therapy for prostate cancer, due to its ability to upstage patients, select patients for LPLND, and alter radiotherapeutic management.