The presence of positive surgical margins in a radical prostatectomy (RP) specimen is an important negative prognostic factor, although the length of the positive margins was not an independent predictive factor for biochemical recurrence (BCR) in most studies. The aim of this study is to correlate the length and the Gleason grade of the positive resection margin with BCR after RP.

The Dutch researchers analyzed the data of 218 consecutive RP specimens with positive surgical margins. All RP specimens were sectioned at 4-mm intervals and completely embedded. Evaluation was done by one uropathologist with regard to the length of the positive margins (mm) and the highest Gleason grade in the positive margins. BCR was defined as two consecutive PSA levels above 0.10ng/ml. Data were analyzed in proportional hazards models.

In 25 patients the post-operative PSA did not drop to zero and another 56 patients received adjuvant hormonal treatment or radiotherapy, leaving a group of 137 patients to be analyzed for BCR. The median follow-up was 38.9 months. In the group of 218 patients, the length of positive margins ranged from 0.4 to 174.5 mm (median 10.0mm; mean 19.1) and was associated with pre-operative PSA 0.001), pathologic stage (p = 0.001), tumor volume (p = 0.032), number of positive sites (p <0.0001) and Gleason grade at the positive margin (p = 0.001), but not with Gleason score (p = 0.06). The distribution of the locations of positive margins was dorsal (43,6%), anterior (33,5%), apical (32,1%), posterolateral (18,8%), basal (18,3%) and at the seminal vesicles (3,7%). The mean length of positive margins of the 25 patients with persistent increased post-operative PSA levels was significantly higher (32.4mm; p=0.005). In the group of 137 patients, the 5-year biochemical recurrence free survival (RFS) rate was 74%. The RFS for patients with positive margins <10mm and >10mm was 80% and 65% respectively. In multivariate analyses BCR was associated with increasing length, but not with preoperative PSA, pathological stage, Gleason score, tumor volume or Gleason grade at the resection margin.

The presenters conclude that the length of positive margins is an independent predictive factor for PSA recurrence.