Impact of Tumor Volume and Other Factors on Renal Function After Partial Nephrectomy

Background and Objectives: One of the main objectives of partial nephrectomy is to preserve as much renal function as possible. However, the removal of functioning nephrons and ischemic damage secondary to the clamping of the renal pedicle can be associated with a certain degree of renal function loss. We aim to evaluate the relationship between tumor volume and other factors on renal function in the short term (1-3 months) and long term (6-12 months) in our series of partial nephrectomies. Methods: A retrospective study was conducted on 147 patients who underwent open or laparoscopic partial nephrectomy between 2018 and 2022. Tumor volume was estimated through reconstructions from the computed tomography images. Univariate and multivariate analyses of the data were performed. Results: The mean age was 58.2 years, with an average glomerular filtration rate (GFR) of 79 mL/min/m². Of all partial nephrectomies, 76.2% were laparoscopic, 57.1% were T1a tumors, and the mean volume was 17 cc. The average ischemia time during surgery was 14.3 min, with a mean hemoglobin loss of 2.8 g/dL in the immediate postoperative period. No significant differences were found either in the short or long term regarding ischemia time (p = 0.57, p = 0.32) or tumor volume (p = 0.57, p = 0.33). However, in the multivariate analysis, it was observed that the variable with the greatest influence on short-term renal function was perioperative glomerular filtration, while in the long term, ischemia time, age, and tumor volume also had an influence. Conclusions: Tumor volume is not an independent factor for renal function deterioration in the short or long term. Short-term renal function is primarily determined by perioperative glomerular filtration. Perioperative glomerular filtration, ischemia time, age, and tumor volume can jointly predict long-term renal function.