R.E.N.A.L. Score Outperforms PADUA Score, C-Index and DAP Score for Outcome Prediction of Nephron Sparing Surgery in a Selected Cohort

Abstract

Purpose: Several nephrometry scores have been proposed to predict perioperative outcomes in renal surgery. We evaluated which nephrometry score correlates best with the MIC (margin, ischemia and complications) score and quantitative perioperative outcomes in nephron sparing surgery.

Materials and methods: Data on 188 patients undergoing nephron sparing surgery were retrospectively investigated for patient, operative and tumor characteristics. Nephrometry scores, including R.E.N.A.L. (radius, exophytic/endophytic properties, nearness of tumor to collecting system or sinus, anterior/posterior, hilar tumor touching the main renal artery or vein and location relative to polar lines), PADUA (preoperative aspects and dimensions used for an anatomical), C-index (concordance index) and DAP (diameter-axial-polar), were measured on preoperative computerized tomography or magnetic resonance imaging and coded continuously and categorically. Parameters pertaining to tumor margin, ischemia and complications were recorded as binary scores and classified as MIC achievement. Operative time, estimated blood loss, warm ischemia time and hospital stay were recorded as quantitative perioperative outcomes.

Results: The R.E.N.A.L. score correlated best with MIC and quantitative perioperative outcomes. The continuously coded R.E.N.A.L. score was predictive of MIC on univariate analysis (OR 0.75, 95% CI 0.58-0.97, p = 0.03) and it had the best predictive value on multivariate logistic regression analysis (OR 0.31, 95% CI 0.18-0.82, p = 0.03). The C-index but not the PADUA or the DAP score was predictive of MIC on univariate and multivariate logistic regression analysis. MIC achievement rates were significantly higher for low than for high complexity tumors as assessed by categorically coded R.E.N.A.L. score, C-index and DAP scores. Continuously coded R.E.N.A.L. and PADUA scores positively correlated with operative time, warm ischemia time and hospital stay. The C-index and the DAP score correlated with warm ischemia time.

Conclusions: Of 4 nephrometry scores the R.E.N.A.L. score correlated best with MIC achievement and quantitative perioperative outcomes of nephron sparing surgery.

Keywords: complications; decision support techniques; ischemia; kidney neoplasms; prognosis.