Renal volume matters: Assessing the association between excisional volume loss and renal function after partial nephrectomy

To investigate the oncological and functional outcomes after partial nephrectomy for clinical stage T1 (cT1) renal cell carcinoma (RCC), and assess the association between excisional volume loss (EVL) and postoperative renal function.

We retrospectively reviewed 150 patients with cT1 RCC undergoing partial nephrectomy from 2002 to 2016. End-point evaluation was assessed by recurrence free survival (RFS), overall survival (OS), stage III and stage IV chronic kidney disease (CKD). Regression models were used to determine the risk factors of CKD after surgery. The relationship between EVL and renal function decline was evaluated using Spearman correlation method.

Ninety patients with clinical stage T1a (cT1a) tumors and 60 patients with clinical stage T1b (cT1b) tumors were included. There were no differences in RFS, OS, and risk of stage III and stage IV CKD between the two groups. In Cox regression models, multivariate analysis showed that preoperative estimated glomerular filtration rate (eGFR) was an independent risk factor for developing stage III (hazard ratio 0.937, P < 0.001) and stage IV CKD (hazard ratio 0.929, P = 0.027). EVL was significantly associated with postoperative eGFR decrease. (Correlation Coefficient = 0.325, P = 0.003).

Patients with cT1a and cT1b RCC have comparable oncological and functional outcome after partial nephrectomy, and preoperative eGFR is an independent factor to predict developing CKD. EVL has influence on the postoperative renal function decline.