[Nephron-sparing surgery is superior to radical nephrectomy in preserving renal function outcome in tumors larger than 4 cm].

Objective: The objective of the present study was to analyse whether nephron-sparing surgery (NSS) was superior to radical nephrectomy (RN) in preserving renal function outcome in tumors larger than 4cm.

Methods: The data from 888 patients who had been operated upon at eight french university hospitals were retrospectively analyzed. Glomerular filtration rate (GFR) pre- and post-surgery was calculated with the abbreviated Modification of Diet in Renal Disease (MDRD) equation. For a fair comparison between the two techniques, all imperative indications for NSS and all GFR<30 mL/min/1.73 m(2) were excluded from analysis. A shift to a less favorable DFG group following surgery was considered clinically significant.

Results: Seven hundred and thirty patients were suitable for comparison. Median age at diagnosis was 60 years (19-88). Tumors measuring more than 4cm represented 359 (49.2%) cases. NSS and RN were performed in 384 (52.6%) and 346 (47.4%) patients, respectively. In univariate analysis, patients undergoing NSS had a smaller risk than RN of developing significant GFR change following surgery. This was true for tumors≤4cm (P=0.0001) and for tumors>4cm (P=0.018). In multivariate analysis, the following criteria were independent predictive factors for developing significant postoperative GFR loss: the use of RN (P=0.001), decreased preoperative DFG (P=0.006), increased age at diagnosis (P=0.001) and increased ASA score (P=0.004).

Conclusion: The renal function benefit offered by elective NSS over RN persists even when expanding NSS indications beyond the traditional 4 cm cut-off.