Differential Use of Partial Nephrectomy for Intermediate and High Complexity Tumors May Explain Variability in Reported Utilization Rates

Abstract

Partial nephrectomy has become a reference standard for tumors amenable to a kidney sparing approach but reported utilization rates vary widely. The R.E.N.A.L. (radius, exophytic/endophytic, nearness of tumor to collecting system or sinus, anterior/posterior, location relative to polar lines and hilar tumor touching main renal artery or vein) nephrometry score was developed to standardize the reporting of tumor complexity with applicability in academic and community based settings. We hypothesized that tumor and surgeon factors account for variable use of partial nephrectomy. Clinical and R.E.N.A.L. nephrometry score data were analyzed on 1,433 cases performed between 2004 and 2011 by a total of 19 surgeons with varying partial nephrectomy utilization rates (0% to 100%) who practiced at a total of 2 academic centers and 1 community based health system. Partial nephrectomy use increased during the study period from 36% before 2007 to 73% for 2010 to 2012 (p <0.0001). Increasing proportions of intermediate and high R.E.N.A.L. nephrometry score tumors were treated with partial nephrectomy during this time (35% to 86% and 11% to 36%, respectively, p <0.0001). Partial nephrectomy use was stable for low complexity tumors at 91% overall. Individual surgeons performed partial nephrectomy for 0% to 100% of intermediate complexity and 0% to 45% of high complexity tumors. On multivariable analysis surgery year, tumor size, each R.E.N.A.L. nephrometry score component, surgeon and annual surgeon volume predicted partial vs radical nephrectomy (each p <0.05). On multivariable analysis several surgeon factors, including surgeon volume, setting, fellowship training, and proportional use of minimally invasive and robotic partial nephrectomy, were associated with higher partial nephrectomy use (each p <0.002). Surgeon and tumor factors contribute significantly to the choice of partial nephrectomy. The significant variation in partial nephrectomy use by individual surgeons appears to be caused by differential treatment for intermediate and high complexity tumors. This may be due to surgical volume, training, setting and the use of minimally invasive techniques.