Incidence of positive surgical margins after biopsy-selected nerve-sparing radical prostatectomy.

OBJECTIVES: The selection criteria for a nerve-sparing radical prostatectomy (NSRP) are not thoroughly investigated and are based mainly on preoperative digital rectal examinations and intraoperative findings. At our institution NSRP is performed only on patients whose preoperative systematic sextant biopsy of the prostate showed only unilateral cancer. To prove the safety of these criteria, we analyzed the incidence of positive surgical margins and tumor progression rate in patients who were selected for an NSRP only by the result of the biopsy. METHODS: Preoperative systematic sextant biopsies revealed unilateral cancer in 69 preoperatively potent men of 289 consecutive prostatic cancer patients (23.9%); contralateral NSRP was performed on these 69 patients. The prostate specimens were investigated by using a 3-mm step-section technique to identify positive surgical margins. Tumor progression was defined as a prostate-specific antigen (PSA) level greater than 0.4 ng/mL in the native and greater than 0.025 ng/mL in the suprasensitive postoperative blood test. Mean follow-up was 15 months (range 6 to 24). RESULTS: In 69 patients who underwent NSRP, 11 positive margins (15.9%) were found. Only 3 patients (4.3%) had a positive margin on the nerve-sparing side. In 220 patients who underwent non-NSRP 59 positive margins (26.8%) were detected. PSA recurrence rate after 12 months was similar in patients with NSRP and non-NSRP. Analysis of systematic sextant biopsies gives safe selection criteria because in approximately 95% the surgical margin on the nerve-sparing side will be negative. CONCLUSIONS: Basing the indication for an NSRP on the results of preoperative systematic biopsies was safe according to margin status and postoperative PSA, when all patients with tumor in one of the three biopsy cores of each side of the prostate were excluded from an NS technique on that side. Such a strict approach will exclude approximately 30% of patients from NSRP unnecessarily because of tumor findings on a prostate side where the cancer is still organ-confined. Less strict criteria, including patients with only well-differentiated cancer and a maximum of one positive biopsy on the evaluated side, seem to be as safe as the described selection. However, data on these patients need further evaluation.