Perioperative outcomes of robotic partial nephrectomy for intrarenal tumors

Intrarenal tumors pose a unique challenge to surgeons due to the lack of visual cues on the kidney surface. Intraoperative ultrasonography has facilitated the management of these tumors during minimally invasive partial nephrectomy. We sought to evaluate the safety, feasibility, and comparative effectiveness of robot-assisted partial nephrectomy (RPN) in the management of completely intrarenal tumors.

Our institutional database was queried for patients undergoing RPN between 2007 and 2013. Patient demographics, tumor characteristics, and perioperative outcomes were compared for patients with intrarenal tumors and tumors with any exophytic component. Patients without available preoperative imaging were excluded from the study.

A total of 297 patients were identified with 30 having completely intrarenal tumors and 267 having some exophytic component. Patient demographics were similar between the two groups. Median tumor size was smaller for the intrarenal group than the exophytic group (2.3 vs 2.7 cm, p=0.015) and nephrometry score was higher for the intrarenal group (9 vs 6, p<0.0001). Tumor characteristics were otherwise similar. Perioperative outcomes were similar between the intrarenal and exophytic groups: estimated blood loss (100 vs 100 mL, p=0.56), operative time (165 vs 162 minutes, p=0.86), warm ischemia time (17 vs 17 minutes, p=0.54), renal cell carcinoma positive surgical margin (0% vs 2.4%, p=0.74), intraoperative complications (0% vs 0.76%, p=0.81), and postoperative complications (6.7% vs 17.6% p=0.76).

RPN is feasible, safe, and effective in the treatment of select intrarenal kidney tumors with outcomes similar to those of partially exophytic tumors. This is likely facilitated by intraoperative ultrasonography. Completely intrarenal kidney tumors should not be automatically relegated to radical nephrectomy or open surgery.