Nephron-sparing surgery is superior to radical nephrectomy in preserving renal function benefit even when expanding indications beyond the traditional 4-cm cutoff

Abstract

Objectives: To analyze to what extent partial nephrectomy (PN) is superior to radical nephrectomy (RN) in preserving renal function outcome in relation to tumor size indication.

Methods and materials: Clinical data from 973 patients operated at 9 academic institutions were retrospectively analyzed. Glomerular filtration rate (GFR) before and after surgery was calculated with the abbreviated Modification of the Diet in Renal Disease equation. For a fair comparison between the 2 techniques, all imperative indications for PN were excluded. A shift to a less favorable GFR group following surgery was considered clinically significant.

Results: Median age at diagnosis was 60 years (19-91). Tumor size was smaller than 4 cm in 665 (68.3%) cases and larger than 4 cm in 308 (31.7%) cases. PN and RN were performed in 663 (68.1%) and 310 (31.9%) patients, respectively. In univariate analysis, patients undergoing PN had a smaller risk for developing significant GFR change following surgery than those undergoing RN did. This was true for tumors≤4 cm (P = 0.0001) and for tumors>4 cm (P = 0.0001). In multivariate analysis, the following criteria were independent predictive factors for developing significant postoperative GFR loss: the use of RN (P = 0.0001), preoperative GFR<60 ml/min (P = 0.0001), tumor size≥4 cm (P = 0.0001), and older age at diagnosis (P = 0.0001).

Conclusions: The renal function benefit carried out by elective PN over RN persists even when expanding nephron-sparing surgery indications beyond the traditional 4-cm cutoff.

Keywords: Chronic renal disease; Glomerular filtration rate; Partial nephrectomy; Renal cell carcinoma; Renal function; Survival.