Objectives: To examine the extent and location of positive surgical margins and their influence on progression.
Methods: Two hundred fifteen consecutive radical prostatectomy specimens, using 2 to 3-mm step-sections, were reviewed. Particular attention was paid to the location and extent of positive margins. Seventy-three patients (34%) with one or more positive margins were subjected to further detailed analysis. Progression was defined as a serum prostate-specific antigen level greater than 0.1 ng/mL and rising. The mean follow-up period was 23.2 months; median 24 months (range 3 to 40).
Results: Margin-positive patients had a significantly higher biopsy tumor grape (P = 0.05) than did margin-negative patients. Capsular preforation was present in 75%, seminal vesicle invasion in 33%, and nodal metastases in 10% of margin-positive patients; in contrast, these tumor characteristics were present in 47%, 8%, and 1% of margin-negative patients, respectively. The extent of involvement of linked margins was focal in 22% and extensive in 66%. An equivocal margin identified as surgical incision into the specimen (due to hemostatic staples, surgical dissection, or retraction) was present in 12%. Seventy-one percent of patients had a positive margin at only one location. Of all 99 positive-margin locations, 40% were apical, 10% anterior, 8% bladder neck, 16% posterolateral, and 25% posterior. Thirty-four percent of margin-positive and 7% of the margin-negative patients demonstrated biochemical progression. Of the 36 patients with a positive margin as their only major risk factor for progression (seminal vesicle and lymph node negative, Gleason score less than 8), 25% have progressed. Progression occurred in 2 of 9 patients with an equivocal positive margin, and 5 of 16 with a single focal-positive margin. A multivariate analysis of margin-positive patients identified tumor volume and grade as the most significant predictors, with the location and extent of the positive margin not significant.
Conclusions: Although more frequent at the prostatic apex, tumor at the inked margin at any location is a risk factor for postoperative biochemical progression.