Purpose: The prognostic significance of capsular incision (CPI) at radical retropubic prostatectomy remains to be defined. To evaluate this we compared prostate specific antigen recurrence for with CPI to that with established pathological groups.
Materials and methods: From January 1998 to December 2000, 409 men underwent radical retropubic prostatectomy at our medical center. CPI was defined as a positive posterior, lateral or posterolateral surgical margin without documented extraprostatic extension (EPE). Excluding patients with preoperative androgen ablation, positive lymph nodes or seminal vesicle involvement there were 129 with organ confined disease and negative surgical margins (pT2/-M), 18 with CPI, 29 with EPE and negative surgical margins (pT3a/-M), and 24 with EPE and positive surgical margins (pT3a/+M). We compared time to biochemical recurrence among these 4 groups using Kaplan-Meier estimates. Cox proportional hazard regression was performed to determine the HR of CPI vs the other groups, while controlling for age, prostate specific antigen, tumor volume and Gleason score.
Results: The 3-year likelihood of freedom from biochemical recurrence in the CPI group was 65%, for pT2/-M it was 96%, for pT3a/-M it was 91% and for pT3a/+M it was 58%. The adjusted HR with the 95% CI showed that the risk of biochemical recurrence with CPI was 8.4 times higher than that with pT2/-M (p = 0.002), 5.9 times higher than that with pT3a/-M (p = 0.046) and the same as that with pT3a/+M (p = 0.840).
Conclusions: Isolated posterior, lateral and posterolateral CPI by our definition occurs not uncommonly and it may represent true incision of the capsule and/or difficulty in diagnosing EPE due to a lack of extraprostatic tissue in the surgical specimen. However, the prognostic significance of CPI as defined appears similar to that of pT3a with positive margins.