Clinical and Pathologic Parameters Predicting Seminal Vesicle Invasion (SVI) Based on 12 Core Prostate Needle Biopsy Protocol
Ji Yoon Yoon, Oleksandr Kryvenko, Daniel Schultz, Mireya Diaz Insua, Nilesh Gupta. Henry Ford Hospital, Detroit, MI
Background: Prostate cancer with SVI indicates poor prognosis. In low risk patients, seminal vesicle sparing surgery provides better operative outcome for erectile function or continence. However, prediction of SVI from nomogram or imaging study may not be sufficient. It is generally known that prostate cancer frequently invades seminal vesicles from the prostate base. The aim of this study is to accurately predict SVI from base involvement and other variables based on 12 core biopsy protocol and evaluate the significance of medial base involvement to SVI.
Design: Patients with SVI on radical prostatectomy were identified in a period from 2009 to 2011. Only patients with corresponding previous 12 core biopsies were selected in the study. A control group consisted of consecutive patients who underwent 12 core biopsy protocol and did not show SVI in subsequent RP. T, Χ2 and Fisher's Exact tests were used for univariate analysis and logistic regression for multivariate analysis.
Results: A total of 55 patients had SVI. Mean serum prostate-specific antigen (PSA) was 8.36 in SVI vs 5.16 in NSVI with high incidence of PSA >10 ng/ml in SVI (16/55) vs NSVI (4/110). Clinical T stage above cT2a was seen in 60% of SVI vs 18.6% of NSVI (p<0.001). SVI group showed higher number of positive biopsy cores (6.45 in SVI vs. 3.11 in NSVI, p<.0001). The frequency of SVI was high when highest Gleason score on 12 core biopsy was ≥437 (67.3% in SVI vs 18.2% in NSVI, p<.0001). Base biopsy was positive in 53/55 (94.5%) patients with SVI, compared with 67/110 (60.9%) patients without seminal vesicle invasion (NSVI) (p<0.0001). SVI was frequently seen with either medial or lateral base involvement, highest Gleason score of ≥437 at the base, high tumor volume in base biopsy and bilateral base involvement (p<.0001). However, on multivariate analysis, only serum PSA, medial base tumor volume and high Gleason score in base were independent predictors of SVI.
|B + ≥G437||MB + ≥G437||LB+ ≥G437||MB+ TV.%||LB+ TV.%||B+ Bilateral||B+ Unilateral|
|SVI +||30/52 (57.7%)||24/47 (51.1%)||24/47 (51.1%)||48.5%||52.1%||29/52 (55.8%)||23/52 (44.2%)|
|SVI -||7/67 (10.4%)||2/32 (6.2%)||6/60 (10%)||7.1%||16.9%||16/67 (23.9%)||51/67 (76.1%)|