CLINICAL AND PATHOLOGICAL SIGNIFICANCE OF THE LEVEL AND EXTENT OF CAPSULAR INVASION IN CLINICAL STAGE T1-2 PROSTATE-CANCER

This study was performed to assess the relationship between the level and extent of prostatic capsular invasion (PCI) by cancer and the clin ical and pathological features and prognosis of early-stage prostate c ancer. We conducted a retrospective analysis of the clinical (age, sta ge, grade, prostate specific antigen [PSA] level) and pathological (tu mor volume, stage, grade, surgical margins) features of 688 patients t reated with radical prostatectomy to determine the pathological featur es and probability of recurrence associated with various levels of PCI . Radical prostatectomy specimens were serially sectioned and examined by whole-mount technique. Progression-free probabilities (PFP) after radical prostatectomy were determined by Kaplan-Meier and Cox proporti onal hazards regression analysis. Progression was defined as a rising serum PSA greater than or equal to 0.4 ng/mL or clinical evidence of r ecurrent cancer. Increasing clinical stage, Gleason grade in the biops y specimen, and pretreatment serum PSA levels were each associated wit h increasing levels of PCI (P < .001). In the radical prostatectomy sp ecimen, increasing levels of PCI were significantly associated with in creasing tumor volume (P < .001), Gleason grade (P < .0001), seminal v esicle involvement (SVI, P < .001) and lymph node metastases (+LN, P < .001). None of 138 patients without capsular invasion had SVI or lymp h node metastases (+LN), and all remained free of progression, even th ough some had large volume (up to 6.26 cm(3)) or poorly differentiated (Gleason sum up to 8) cancers. Invasion into the capsule (n = 271) wa s occasionally associated with SM (6%) or +LN (3%) and a significantly (log-rank test) lower PFP of 87% at 5 years. Focal and extensive extr aprostatic extension (EPE) were associated with progressively increase d risk of SVI and +LN and lower PFP (73% and 42%, respectively). In a multivariate analysis, the level of PCI was an independent prognostic factor (P < .001). There is a strong association between the level of invasion of cancer into or through the prostatic capsule and the volum e, grade, pathological stage, and rate of recurrence after radical pro statectomy. Prostate cancer does not appear to metastasize in the abse nce of invasion into the capsule regardless of the volume or grade of the intracapsular tumor. Subclassification of patients according to th e levels of PCI provides valuable prognostic information. Copyright (C ) 1998 by W.B. Saunders Company.