Prediction of capsular perforation and seminal vesicle invasion in prostate cancer

Capsular perforation and seminal vesicle invasion are unfavorable prognostic factors in prostate cancer. Accurate preoperative prediction of these factors would be clinically useful for planning treatment, especially in patients being considered for radiation therapy, nerve sparing radical prostatectomy and watchful waiting. However, current methods are imprecise at predicting the presence and extent of these factors. We determined which combination of commonly available preoperative variables provides the best prediction of capsular perforation and seminal vesicle invasion of patients with clinically localized prostate cancer.

We reviewed the preoperative medical records and biopsy findings from 314 patients with clinical stages T1cN0M0 to T2cN0M0 cancer who underwent radical retropubic prostatectomy and bilateral pelvic lymphadenectomy between September 1991 and June 1993. Radical prostatectomy specimens were embedded and evaluated by whole mount sections.

Capsular perforation was observed in 104 patients (33.1%) and seminal vesicle invasion was noted in 46(14.6%). Preoperative variables predictive of capsular perforation and seminal vesicle invasion on univariate analysis were serum prostate specific antigen (PSA) concentration, clinical, stage, Gleason primary and secondary patterns, Gleason score, nuclear grade, perineural invasion and percent cancer in the biopsy specimens. On multivariate analysis, independent prognostic factors for capsular perforation and seminal vesicle invasion were PSA, Gleason score and percent cancer in the biopsy specimens.

The combination of serum PSA concentration, Gleason score and percent cancer in the biopsy specimens provides the best prediction of capsular perforation and seminal vesicle invasion. Models based on this combination of factors may be clinically use to stratify patients for nonoperative treatment.