Three-year oncologic and renal functional outcomes after robot-assisted partial nephrectomy

Abstract

Background: With the wider adoption of minimally invasive partial nephrectomy (PN), intermediate- and long-term outcomes data are needed to make firm conclusions about oncologic and functional efficacy, especially for robot-assisted PN (RPN).

Objective: To report intermediate-term oncologic and renal functional outcomes of RPN.

Design, setting, and participants: We performed a chart review of patients who had undergone RPN since June 2006; patients with a minimum of 2 yr of follow-up were included in this study. Length of follow-up was calculated from the date of surgery to the date of last clinical follow-up. Patients who were either lost to follow-up or who had follow-up outside of our center were sent surveys.

Intervention: Transperitoneal RPN with or without hilar clamping.

Outcome measurements and statistical analysis: The demographic, preoperative, and postoperative data were statistically analyzed. The Kaplan-Meier method was used to calculate overall survival (OS), cancer-specific survival (CSS), and cancer-free survival (CFS). Upstaging of chronic kidney disease (CKD) was calculated, as well. Univariate and multivariate analyses were performed to show predicting factors for the latest estimated glomerular filtration rate (eGFR).

Results and limitations: Of 427 patients, 134 had a minimum follow-up of 2 yr, and 70 had a minimum of 3-6 yr of follow-up. The mean age was 59.1±12.5 yr, body mass index (BMI) was 29.8±6.2 kg/m(2), and Charlson comorbidity index (CCI) score was 4.2±1.6. The mean tumor size on computed tomography (CT) scan was 3.0±1.6 cm, RENAL score was 7.2±1.8, estimated blood loss (EBL) was 270.7±291.9 ml, operative time was 189.1±54.8 min, and warm ischemia time (WIT) was 17.9±10.3 min. A total of two intraoperative complications (1.5%) and five high-grade Clavien complications (3.7%) occurred. Patients stayed on average for 3.7±1.7 d in the hospital, and the average follow-up was 3.0±0.9 yr. OS was 97.01% at 3 yr and 90.20% at 5 yr; CFS was 98.92% at 3 yr and 98.92% at 5 yr; and CSS was 99.04%, as projected by the Kaplan-Meier method. The mean preoperative GFR was 88.2±0.8 ml/min per 1.73 m(2); the latest postoperative GFR was 80±24 ml/min per 1.73 m(2), with a 8±17.4% change. There was a 20.2% upstaging of CKD postoperatively, but no patients started dialysis.

Conclusions: This study reaffirms that RPN is effective in renal function preservation and oncologic control at an intermediate follow-up interval.

Keywords: Follow-up; Kidney; Nephron sparing; Outcomes; Renal cancer; Robotic partial nephrectomy.