A comparison of DAP and RENAL scoring systems in the achievement of trifecta in laparoscopic partial nephrectomy

Abstract

Purpose:

The concept of ‘trifecta’ outcome postulated for radical prostatectomy has been adopted for partial nephrectomy, the gold standard for management of small renal masses. We sought to evaluate the role of nephrometry scores in predicting outcomes in terms of the trifecta. We compared two scoring systems for renal tumour complexity (RENAL and DAP) in the prediction of trifecta outcomes.

Materials and methods:

Sixty-nine patients who underwent laparoscopic PN (LPN) were evaluated in a single-centre retrospective study (2010–2017). RENAL and DAP scores were measured. Parameters relevant to the trifecta were tabulated.

Results:

When comparing the two scoring systems in terms of warm ischaemia time (WIT), the DAP score could predict with statistically significant accuracy the completion of resection within 25 mins of WIT. Tumours were more evenly distributed according to anatomical characteristics with the DAP scoring system than with the RENAL scoring system. When comparing these systems in terms of complications, neither predicted complications based on complexity with significant accuracy. A low RENAL score predicted trifecta achievement in three-fourth (71.4%) of patients, while a medium RENAL score predicted trifecta achievement in half (54%) of patients. DAP score predicted trifecta achievement in all tumours with a low score, two-third (66%) in medium and less than half (42%) with a high score. Predictions based on DAP were accurate and significantly so (p = 0.024).

Conclusions:

DAP score predicted the outcomes of LPN in terms of trifecta significantly better than the RENAL score. In our experience, the DAP score was able to distribute tumour complexity among its groups more effectively than the RENAL score. There is early evidence that the DAP score may be more useful than the RENAL score for decision-making in nephron sparing surgery. This is especially pertinent for small renal masses at the upper limits of tumour complexity for which minimally invasive techniques can be safely applied.