ADENOCARCINOMA OF THE PROSTATE INVADING THE SEMINAL-VESICLE - DEFINITION AND RELATION OF TUMOR VOLUME, GRADE AND MARGINS OF RESECTION TO PROGNOSIS

An issue relating to uniformity in pathological staging of prostate ca ncer that has received relatively minimal attention is that of seminal vesicle invasion. Several studies define tumor in the peri-seminal ve sicle soft tissue as seminal vesicle invasion, while others equate sem inal vesicle invasion with tumor invading the muscular wall of the sem inal vesicle. There are also controversies regarding the prognostic si gnificance of seminal vesicle invasion compared to capsular penetratio n, and whether seminal vesicle invasion is a predictor of poor prognos is independent of tumor volume and grade. We evaluated 115 cases of es tablished capsular penetration, 16 of peri-seminal vesicle invasion an d 45 of seminal vesicle invasion in patients without lymph node metast ases. Patients with seminal vesicle invasion had a significantly worse prognosis than those with capsular penetration; peri-seminal vesicle invasion was associated with an intermediate risk of progression. Glea son grade, surgical margins and seminal vesicle invasion were all inde pendent predictors of progression in a multivariate analysis, whereas tumor volume was not. In patients with seminal vesicle invasion there was a trend for surgical margins and Gleason grade to predict progress ion; with tumor volume there was none. Our study demonstrates that the definition of seminal vesicle invasion should be restricted to tumors showing infiltration into the muscular wall of the seminal vesicle. O ur study further demonstrates that when assessing the ability of new p rognostic variables to predict prognosis of patients with seminal vesi cle invasion, margins of resection and Gleason grade should be conside red.