Editorial comment on: preservation of renal function following partial or radical nephrectomy using 24-hour creatinine

In the past 10 years, partial nephrectomy (PN) has become the standard of care for patients with tumour ≤4 cm. It has been widely demonstrated that oncological control after PN is equivalent to that following radical nephrectomy (RN) and that renal function preserved for quality of life is better after nephron-sparing surgery [1], [2] and [3]. Renal function after RN decreases significantly over time related to the development of a focal glomeruloscerosis because of hyperfiltration by the remaining nephrons. The severity of the glomerulosclerosis correlates with the number of removed nephrons. To prevent or avoid hyperfiltration when treating a small renal mass, it is essential to preserve the highest number of nephrons. This goal can be achieved by performing PN in eligible patients and by resecting few millimetres of healthy parenchyma during PN. The assessment of renal function should be estimated with the glomerular filtration rate (GFR). The best methods for estimating GFR are the plasmatic clearance of inuline and the 51Cr-ethylenediaminetetraacetic acid (EDTA) scientigraphy [4]. Urinary creatinine clearance or GFR estimate equations (Cockcroft-Gauldt) can be considered as surrogates. Clark et al's well-designed, prospective study [5] compares the GFR obtained with the two above-mentioned surrogates to assess renal function after PN and RN. The authors demonstrate in a small series that patients undergoing RN had a 25.5% greater decline in their renal function compared to those who underwent PN. They state that the best method for evaluating global renal function is the 24-h creatinine clearance. These authors should be congratulated, first, for using a scientific method to evaluate overall renal function that can be considered in the design of other urological trials and, second, especially for stressing the functional benefits of an underutilized procedure such as PN.