Findings of routine apical margin biopsy during robot-assisted radical prostatectomy

Intraoperative biopsy of the apical margin during radical prostatectomy has been recommended as a way to reduce the positive margin rate at this location. However, the enhanced visibility of the apex during robot-assisted radical prostatectomy (RARP) may obviate this need, allowing for the preservation of maximal urethral length. We assessed pathologic findings of routine apical margin biopsy intraoperative frozen section (IFS) during RARP.

The Columbia University Robotic Database was retrospectively reviewed to identify men who underwent RARP with biopsy of the apical soft tissue (urethroprostatic junction). Both IFS and permanent section samples were analyzed. The clinical characteristics associated with IFS and permanent section histological findings were assessed.

In total, 335 men underwent RARP with apical biopsy from December 2007 to August 2011. Of these, 329 had IFS available for analysis. Median age and prostate-specific antigen level were 60 years (range, 42-78 years) and 5.2 ng/mL (interquartile range, 4.1-6.9 ng/mL), respectively. Of the 329 apical IFS cases, cancer was detected in 9 patients (2.7%), benign prostatic glands in 135 (41%), and nonprostatic tissue in 185 (56.3%). On permanent section, cancer was seen in 9 patients (2.7%), benign prostatic glands in 125 (38%), and nonprostatic tissue in 195 (59.3%). False-positive and false-negative rates of detecting cancer on IFS were 33% (3/9) and 1% (3/320), respectively. The overall positive surgical margin rate was 11%.

Cancer is rarely detected by IFS analysis of routine biopsy of the apical margin during RARP. Although routine IFS may not be beneficial for all patients, selective utilization of IFS may be useful in directing apical dissection in men with apical tumors, allowing for the preservation of maximal urethral length.