Transperitoneal Robot-assisted Partial Nephrectomy with Minimum Follow-up of 5 Years: Oncological and Functional Outcomes from a Single Institution

Background: Robot-assisted partial nephrectomy (RAPN) is an established, minimally invasive nephron-sparing technique with excellent perioperative and intermediate oncological outcomes. However, long-term oncological outcomes have not been reported to date. Objective: To report oncological and functional outcomes of RAPN among patients with minimum follow-up of 5 yr. Design, setting, and participants: Data for consecutive patients undergoing RAPN since October 2006 were extracted from a prospectively-maintained institutional PN database. Patients with benign tumors, genetic mutations, prior radical or ipsilateral PN, and those with follow-up of <5 yr were excluded. Intervention: Transperitoneal RAPN for renal cell carcinoma (RCC). Outcomes measurements and statistical analysis: Demographic, perioperative, postoperative, functional, and oncological data were evaluated. A linear random-effects model was used to estimate the effect of follow-up duration on the estimated glomerular filtration rate (eGFR) after adjustment for potential confounders. Univariable competing-risks regression analyses were performed to evaluate the hazard ratio (HR) for cancer-related events for the variables of interest. Results and limitations: A total of 278 RAPNs for RCC were included. eGFR was significantly lower at follow-up time points than at baseline. At last follow-up (median 46 mo, interquartile range 30-58) the mean eGFR difference was -10.6ml/min (95% confidence interval -12.56 to -8.66; p < 0.0001). There were 28 deaths (10.1%) in the cohort during the follow-up period, of which five (1.8%) were related to metastatic RCC. The 5-yr and 7-yr cumulative incidence of RCC deaths was 1.80% at both 5 and 7 yr, while the cumulative incidence of local recurrence was 3.61% and 4.16%, and that of metastasis was 3.24% and 4.57% at 5 and 7 yr, respectively. Univariable competing-risks regression revealed that higher Fuhrman grade (HR 8.76; p = 0.051), larger tumor size (HR 1.67; p < 0.0001), and tumor necrosis (HR 16.73; p = 0.0019) were independent predictors of RCC death. The retrospective design and potential selection bias due to patient selection in the early RAPN experience may limit the generalizability of the findings. Conclusions: This is the first study reporting minimum oncological follow-up of 5 yr after RAPN. The results demonstrate excellent long-term oncological outcomes after RAPN in a selected cohort of patients. Our data confirm that the renal functional deterioration after RAPN remains stable over time after the early postoperative decrease.