Presentation Authors: Ashley Shumate*, Isabella Galler, Colleen Ball, Kaitlynn Custer, David Thiel, Jacksonville, FL
Introduction: To evaluate renal tumor contact surface area (CSA) as a tool for predicting outcomes of robotic partial nephrectomy (RAPN).
Methods: 360 consecutive RAPNs were analyzed from a prospectively-maintained database. We calculated CSA for all renal tumors with the formula proposed by Hsieh et al. (2016): CSA= 2*Ï€*r*d, where Ï€ â‰ˆ 3.14, r = tumor radius (cm), and d = tumor depth (cm). We analyzed patient and tumor characteristics, pathology, and intraoperative/postoperative outcomes and their association with CSA. Patients were excluded if they had prior RAPN (n=7), had RAPN for calyceal diverticulum (n=4), if >1 tumor removed during RAPN (n=9), or if all variables were not available for calculating CSA (n=8) for a final cohort of 332. After adjusting for multiple tests, pâ‰¤0.017 was considered statistically significant.
Results: Median age was 63 years and 132 (39.8%) patients were female. Median CSA was 12.2 cm2. Median warm ischemia time was 18 minutes, median length of stay (LOS) was 2 days, 20 patients (6.0%) had a post-operative complication of Grade III or higher, and median percent change in estimated glomerular filtration rate (eGFR) from preoperative to 1 month after RAPN was -11.4%. Higher CSA was associated with higher warm ischemia time (WIT) (Spearman correlation [rs]=0.52, P < 0.001), higher estimated blood loss (EBL) (rs=0.27, P < 0.001), and longer LOS (rs=0.24, P < 0.001). Higher CSA was also associated with decreased eGFR at post-operative day 1 and 1 month after RAPN when evaluated based on both absolute change and percent change in eGFR from baseline (all Pâ‰¤0.001). The association between CSA and change in eGFR from baseline to 6 month postop was not statistically significant after adjustment for multiple testing, but eGFR was not available for 110 patients at 6 month postop.
Conclusions: Higher CSA is associated with longer WIT, higher EBL, LOS, and worse renal function after RAPN, but is not associated with post-operative complications after RAPN. CSA may have some benefit as a pre-operative tool for predicting intraoperative and post-operative outcomes of RAPN.