Effect of adherent perinephric fat on outcomes of nephron-sparing treatment of renal cell cancer

Abstract

Introduction. Nephrometric scales have been developed to determine the appropriate surgical tactics and to predict intraoperative values more accurately, considering the characteristics of the renal tumour. However, there is a need to assess the perinephric fat. The Mayo Adhesive Probability (MAP) scale aims to identify adherent perinephric fat (APF) or 'complex' paranephric fat preoperatively.Objective. To evaluate the effect of APF on intraoperative and functional outcomes of patients with renal cell cancer (RCC) who underwent laparoscopic partial nephrectomy.Materials & methods. We analysed 118 patients with localised RCC who underwent laparoscopic partial nephrectomy. At the preoperative stage, according to the results of contract-enhanced msCT, the presence of APF was assessed using the MAP scale. At the same time, the thickness of the posterior perinephric fat was measured and the grade of its twisting was assessed. As a result, the patients were divided into two groups: group 1 MAP 0 – 2 pts (no APF) 34 patients and group 2 MAP 3 – 5 pts (presence of APF) 84 patients. In each group, the following indicators were assessed: stage according to the TNM classification, mean age and BMI, average nephrometry score according to the R.E.N.A.L. system, glomerular filtration rate (GFR).Results. The median surgery time for group 1 patients was 115.0 [92.5; 142.5] min, for group 2 — 130.0 [101.3; 180.0] min. The median warm ischemia time in patients in group 1 was 15 [0; 20] min, in group 2 — 12 [0; 18] min. The median blood loss in the groups 1 and 2 was 50 [15; 100] and 50 [0; 100] ml, respectively. The mean GFR on the first day after surgery was 63.34 ± 18.40 ml/min/1.73 m2 in group 1 and 55.09 ± 16.01 ml/min/1.73 m2 in group 2. Openings of the pyelocalyceal system were observed in 8 (23.53%) and 23 (27.38%) patients in groups 1 and 2, respectively. A positive surgical margin was detected one patient in group 1 and two in group 2. Early postoperative complications in group 1 were four patients and group 2 — 15 patients.Conclusion. The presence of APF and its severity can be effectively assessed using the MAP score, which is promising, but is limited only to the prognostic of APF without correlation with nephrometric scales that assess tumour anatomy parameters. However, the issue of developing a unified assessment system that includes APF and kidney morphometry is currently open, and the definition of APF is still subjective and requires an objective analysis to obtain more accurate outcomes.