Margin Status After Laparoscopic Radical Prostatectomy and the Index Lesion: Implications for Preoperative Evaluation of Tumor Focality in Prostate Cancer

Abstract

The objective of this study was to evaluate the impact of tumor focality on positive surgical margins (PSM) after laparoscopic radical prostatectomy. Ninety-five consecutive whole-mount laparoscopic radical prostatectomy samples (January 2007 to November 2009) were evaluated for tumor focality, laterality, Gleason score, and volume of individual foci, total tumor volume, pathologic stage, and surgical margin status. Thirty-nine percent, 36%, and 25% were in low, intermediate, and high D'Amico risk categories. Thirty-three percent (31/95) had PSM. Overall, 269 tumor foci were identified. The incidence of PSM within lesions ≤ 0.5 cc and ≤ 0.2 cc was 1.2% (2/160) and 0% (0/132), respectively. Among the 71 multifocal cases, 19 (27%) exhibited PSM. In 13 of these, the index lesion appeared at the inked surface (mean volume 5.4 cc, range 0.63-26.9 cc) compared with 6 in which both index and satellite foci appeared at the inked margins. Mean volume of these satellite foci was 1.06 cc (range 0.22-2 cc); three had Gleason score 6 and three had Gleason score 7 (3+4). PSM is usually attributed to the index lesion and lesions larger than commonly used thresholds for clinically significant lesion volumes. Because such lesions might be detected by multiparametric magnetic resonance imaging (MRI) or template mapping biopsies, the information from these staging modalities could be used intraoperatively to reduce PSM.