A rational analysis of the commonly used renal tumor scoring systems in predicting surgical outcomes of cystic renal masses

Abstract

Objective: To explore the predictive effect of the renal tumor scoring system on the surgical outcomes of cystic renal masses (CRMs). Methods: A retrospective analysis was performed on the data of 234 patients who received robotic-assisted partial nephrectomy (RAPN) treatment in the First Affiliated Hospital of Xi'an Jiaotong University from January 2018 to June 2020. And 31 cases had cystic renal masses (CRM) and 203 cases had solid renal masses (SRM). The propensity score of patients was calculated by logistic regression model, and 1∶2 matching was performed by the nearest neighbor method. The changes in perioperative indexes and long-term estimated glomerular filtration rate (eGFR) in CRM group and SRM group were compared. The CRM group and SRM group were stratified according to the complexity grading of R.E.N.A.L. score and PADUA score, respectively, to compare the difference in the achievement rate of ideal surgical outcome between the two groups, and analyze the predictive factors affected. The CRM diameter was stratified with 4 cm as the cut-off value (CRM1 group with a diameter<4 cm, CRM2 group with a diameter≥4 cm), and the surgical results were compared with the matched SRM1 group and SRM2 group. Results: In the matching cohort, the CRM group comprised 29 patients with a mean age of (48.7±10.8) years, of which 22 (75.9%) were males. The SRM group included 58 patients with a mean age of (50.4±10.2) years, of which 41 (70.7%) were males, with no statistically significant difference (all P>0.05). The warm ischemia time (WIT) [M (Q1,Q3)] in the CRM group was longer than that in the SRM group [23(18, 25) vs. 19(17, 25) min, P=0.040]. The operation time (OT) [M (Q1,Q3)] in the CRM group was also longer than that of the SRM group [130(100, 150) vs. 107.5(86.25, 120) min, P=0.006]. The change in serum creatinine before and after the operation [M (Q1,Q3)] was higher in the CRM group than in the SRM group [15(9, 23) vs 11.5(6, 16.75) μmol/L, P=0.030]. The ideal surgical outcomes were achieved in 7 patients (24.1%) in the CRM group and 36 patients (62.1%) in the SRM group. The number of patients achieving ideal surgical outcomes in R.E.N.A.L. intermediate complex surgery and PADUA advanced complex surgery in the SRM group were 24 (58.5%) and 15 (51.7%), respectively, which were higher than those in the CRM group 6 (27.3%) and 1 (5.9%) respectively (P<0.05). Preoperative eGFR (OR=0.758, 95%CI: 0.719-0.799) and the nature of the tumor (CRM as reference, OR=4.883, 95%CI: 1.550-15.378) were influencing factors for achieving the ideal surgical outcome. Subgroup analysis showed that eGFR changes before and after surgery and the estimated blood loss (EBL) in the CRM2 group were higher than those in the SRM2 group, and WIT and OT were longer than those in the SRM2 group (all P<0.05). The EBL and WIT of the CRM1 group were shorter than those of the CRM2 group (P<0.05). Conclusion: The surgical risk of RAPN in complex CRMs with a maximum diameter of≥4 cm is higher than the risk of RAPN in SRM with equivalent R.E.N.A.L. and PADUA scores.