[Seminal vesicle invasion afer radical prostatectomy: study of risk factors for progression].

Objective: Seminal vesicle invasion (pT3b) is a known factor of poor prognosis after radical prostatectomy. The authors retrospectively studied the course of stage pT3b tumours, and the clinical, laboratory and histological factors that could influence this course.
Methods: From 1988 to 2001, out of a total of 538 radical prostatectomies, 62 (11.5%) cases with isolated seminal vesicle invasion were analysed according to the Stanford technique. Half-yearly postoperative surveillance was based on physical examination and PSA assay. Progression was defined as PSA greater than 0.2 ng/ml or when complementary treatment was performed. Actuarial progression-free survival was studied according to the Kaplan-Meier method. Actuarial survivals were compared by the Log-rank method, and a difference was considered to be significant for p < 0.05. Multivariate analysis using the Cox model was performed.
Results: The mean Gleason score of the radical prostatectomy specimen was 6.9, and the mean tumour volume was 2.7 cm3. Forty eight (77.4%) specimens showed capsular effraction and 33 (53.2%) had positive surgical margins. The 5-year laboratory progression-free survival was 16%. A low preoperative PSA, a radical prostatectomy specimen Gleason score less than 7 and capsular effraction were factors of good prognosis on multivariate analysis.
Conclusion: Prostatic tumours with seminal vesicle invasion have a high risk of progression after radical prostatectomy. A preoperative PSA level less than 10 ng/ml, a Gleason score of the operative specimen less than 7 and effraction of the prostatic capsule can be used to identify a subpopulation of patients with a better prognosis.