Predictive factors of renal function after robot-assisted partial nephrectomy in clinical T1b tumors

Robot-assisted partial nephrectomy (RAPN) has been shown to be a safe and effective method for treatment of small renal tumors, including clinical T1b renal cell carcinoma (RCC); however, the impact of RAPN for cT1b renal tumors on renal function is not well understood. In this retrospective study, 50 patients who underwent RAPN for cT1b renal tumors were evaluated for pre- and post-operative renal function and perioperative clinical factors. Renal function was assessed using the estimated glomerular filtration rate (eGFR) at baseline and on postoperative days (POD) 1, 7, 30, and 180.A significant renal functional decline was defined as ≥ 15% reduction in eGFR at POD180 compared with eGFR at baseline. Logistic regression analyses were used to identify risk factors for renal function decline, including age, sex, RENAL nephrometry score, operative time, and estimated blood loss. The median patient age was 62 years, and the median tumor diameter and RENAL nephrometry score were 44 mm (IQR 43-50) and 8 (IQR 7-9), respectively. Of these patients, 16 (36%) showed a significant renal functional decline at POD 180. In the multivariate analysis, the L component of the RENAL nephrometry score and an estimated blood loss of 200 mL or more were identified as significant risk factors for renal functional decline. These findings suggest that the preoperatively definable L component of the RENAL nephrometry score and intraoperative blood loss, which may be modifiable factors, play significant roles in post-RAPN renal function decline.