The SPARE score reliably predicts the conversion from open partial to radical nephrectomy.

To assess the power of nephrometry scores to predict the intraoperative conversion from partial nephrectomy (PN) to radical nephrectomy (RN). We identified all the patients at our institution who were scheduled for PN between April 2012 and December 2017. Patients who underwent robotic or laparoscopic surgery were excluded. A total of 149 patients (94 men) who underwent open surgery and had complete data were included. The power of the R.E.N.A.L., PADUA, SPARE, and DAP scores to predict the conversion to RN, and the threshold values were assessed. In the multivariate analysis, the predictive power of the nephrometry scores was tested by separately including them in different models. The median age was 57 (48-67) years, while the median follow-up was 15 (7-29.5) months. The overall conversion rate was 10.7%. The optimal cut-off values for the R.E.N.A.L., PADUA, SPARE, and DAP scores were 7.5, 9.5, 5.5 and 7.5, respectively. The SPARE score had the highest area under the curve (AUC=0.807, P<0.001). In the multivariate analysis, the SPARE score had the highest odds ratio (OR 12.561; confidence interval 3.456-45.534, P<0.001]. A high SPARE score was significantly associated with the conversion to RN in patients who underwent open PN.