High R.E.N.A.L. nephrometry score is associated with partial to total nephrectomy conversion, in treatment of renal cancer

Abstract

Aim: To test the hypothesis that R.E.N.A.L. nephrometry score is able to predict surgical conversion, from laparoscopic to open nephrectomy, or totalization, from partial to total nephrectomy. Methods: Between January 2010 and June 2012, 320 patients underwent radical or partial nephrectomy at a Tertiary Institution, of which 173 (54.1%) had a tumor <7cm. Of these, 71 (41%) patients were selected for the prospective study according to inclusion and exclusion criteria. Score's accuracy in predicting surgical conversion rate was analyzed by using ROC curve and it's best cutoff point was identified. Results:The accuracy of R.E.N.A.L. nephrometry score in predicting conversion rate demonstrated an AUC of 0.715 (95% CI: 0.595-0.836; p=0.002). By evaluating a cutoff point, it was found 46% sensitivity and 78% specificity for R.E.N.A.L. >9. From patients who underwent totalization, 4/46 (8.9%) had a R.E.N.A.L. score <9 and 7/25 (28%) had a R.E.N.A.L. score ≥9, OR 4.08, p=0.03. Conclusion:R.E.N.A.L. nephrometry score can help predicting the need of total nephrectomy or conversion to open surgery. Renal unit loss was associated with high complexity tumors (score ≥9), with this cutoff point representing a fourfold higher chance of conversion from partial nephrectomy to radical in treatment of renal cancer.