[Value of nephron preservation in conservative surgery of renal tumors].
The increasing use of abdominal ultrasonography and computed tomography results in the increasingly early diagnosis of subclinical renal tumours. These asymptomatic tumours can sometimes be treated conservatively. This technique raises the problem of the multifocal nature of renal tumours In order to assess the real benefit of nephron-sparing surgery in relation to the risk of recurrence, this study evaluates the repercussions of exclusive tumour resection on the nephron number. From 1990 to 1995, 28 patients underwent partial nephrectomy for suspected renal cell carcinoma. Computed tomography was use to estimate the volume and therefore the weight of the kidney and the tumour: weight (g) = volume (mL) = length x width x height/2. The mean age of the patients was 59.1 years. The contralateral kidney was normal in 20 patients (group 1) and the tumour affected a solitary kidney in 8 patients (group 2). The initial serum creatinine level was normal (between 78 and 96) in all patients. The mean weight of the tumour was 16.1 g (13.6 g for group 1 and 22.3 g for group 2), and corresponded to 3.84% of the total kidney weight in group 1 and 9.73% in group 2. 1,400,000 nephrons were preserved in group 1 versus 900,000 nephrons in group 2, equivalent to a glomerular filtration rate of 89 mL/min and 58 mL/min, respectively. Partial nephrectomy therefore constitutes a real nephron-sparing technique. It allows sparing of a sufficient number of nephrons to ensure normal renal function and, most importantly, allows the possibility of subsequent partial surgery in view of the potential risk of multifocal tumours.