Obese men undergoing radical prostatectomy: Is robotic or retropubic better to limit positive surgical margins? Results from SEARCH.

To evaluate the association between obesity and positive surgical margins in patients undergoing retropubic radical prostatectomy versus robotic-assisted laparoscopic prostatectomy.

We retrospectively reviewed the data of 3141 men undergoing retropubic radical prostatectomy and 1625 undergoing robotic-assisted laparoscopic prostatectomy between 1988 and 2017 at eight Veterans Health Administration hospitals.

The positive surgical margin location (peripheral, apical, bladder neck, overall) was determined from pathology reports. We adjusted for age, race, prostate-specific antigen, surgery year, prostate weight, pathological grade group, extracapsular extension, seminal vesicle invasion, hospital surgical volume and surgical method (in analyses not stratified by surgical method). Interactions between body mass index and surgical approach were tested.

Among all patients, higher body mass index was associated with increased odds of overall, peripheral and apical positive surgical margins (OR 1.02-1.03, P ≤ 0.02). Although not statistically significant, there was a trend between higher body mass index and increased odds of bladder neck positive surgical margins (OR 1.03, P = 0.09). Interactions between body mass index and surgical method were significant for peripheral positive surgical margins only (P = 0.024). Specifically, there was an association between body mass index and peripheral positive surgical margins among men undergoing retropubic radical prostatectomy (OR 1.04, P < 0.001), but not robotic-assisted laparoscopic prostatectomy (OR 1.00, P = 0.98). Limitations include lacking individual surgeon data and lacking central pathology review.

In this multicenter cohort, higher body mass index was associated with increased odds of positive surgical margins at all locations except the bladder neck. Furthermore, there was a significant association between obesity and peripheral positive surgical margins in men undergoing retropubic radical prostatectomy, but not robotic-assisted laparoscopic prostatectomy. Long-term clinical significance requires further study.

International journal of urology : official journal of the Japanese Urological Association. 2020 Jul 17 [Epub ahead of print]

Farnoosh Nik-Ahd, Lauren E Howard, William J Aronson, Martha K Terris, Zachary Klaassen, Matthew R Cooperberg, Christopher L Amling, Christopher J Kane, Stephen J Freedland

David Geffen School of Medicine, University of California, Los Angeles, California, USA., Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina, USA., Department of Urology, UCLA School of Medicine, Los Angeles, California, USA., Division of Urology, Veterans Affairs Medical Center, Augusta, Georgia, USA., Section of Urology, Department of Surgery, Augusta University Medical College of Georgia, Augusta, Georgia, USA., Department of Urology, Oregon Health and Science University, Portland, Oregon, USA., Department of Urology, University of California San Diego Health System, San Diego, California, USA., Section of Urology, Veterans Affairs Medical Center, Durham, North Carolina, USA.