Renal Tumor Contact Surface Area: A Novel Parameter for Predicting Complexity and Outcomes of Partial Nephrectomy

Abstract Background The contact surface area (CSA) of a tumor with adjacent renal parenchyma may determine the complexity and thus the perioperative outcomes of partial nephrectomy (PN). Objective We devised a novel imaging parameter, renal tumor CSA, and correlate it with perioperative outcomes in patients undergoing PN. Design, setting, and participants Of 200 patients undergoing PN for a tumor (January 2010 to August 2011), 162 had renal protocol computed tomography scanning data available. CSA was calculated using image-rendering software (Synapse 3D, Fujifilm), and interobserver variability was determined between three independent observers. Outcome measurements and statistical analysis CSA was correlated to baseline demographics and perioperative outcomes as a continuous and categorical variable using multivariable logistic regression analysis. The ability of CSA to predict adverse perioperative events was compared with demographic factors and nephrometry scoring systems. Results and limitations The mean tumor size was 3.1 cm; CSA was 18.3 cm2 . CSA ≥20 cm2 correlated with adverse tumor characteristics (greater tumor size, volume, and complexity) and perioperative outcomes (more parenchymal volume loss, blood loss, and complications) compared with CSA