Robot-assisted partial nephrectomy: Can retroperitoneal approach suit for renal tumors of all locations?—A large retrospective cohort study

BACKGROUND: This study aimed to explore the appropriate location of renal tumors for retroperitoneal approach. MATERIALS AND METHODS: We retrospectively analyzed 1040 patients with renal tumor who were treated at our institution from Janurary 2015 to June 2020 and had underwent retroperitoneal robotic assisted-laparoscopic partial nephrectomy (rRAPN). Clinical features and postoperative outcomes were evaluated. RESULTS: Patients with incomplete data were excluded, and we included 896 patients in total. The median tumor size was 3.0 (range: 0.8–10.0) cm. The median RENAL Nephrometry Score was 7 (range: 4–11), and the median PADUA Nephrometry Score was 8 (range: 6–14). The median surgical time was 120 min, and the median warm ischemia time was 18 min. The median estimated blood loss was 50 ml. The follow-up time was 20.2 (range: 12–69) months. The mean change of eGFR 1 year after operation was 14.6% ± 19.0% compared with preoperative estimated glomerular filtration rate (eGFR). When compared the tumor at different locations, as superior or inferior pole, anterior of posterior face of kidney, there were no significant differences of intra- and post-operative outcomes such as surgical time, warm ischemia time, estimated blood loss, removal time of drainage tube and catheter, postoperative feeding time and hospital stay, and changes of eGFR one year after surgery. We also compared tumors at special locations as endophytic or exophytic, anterior of posterior hilus of kidney, there were no significant differences in surgical time, warm ischemia time, estimated blood loss and changes of eGFR. There was no significant difference in intraoperative features and postoperative outcomes when tumor larger than 4 cm was located at different positions of kidney. Though the surgical time was longer when BMI ≥ 28 (132.6 min vs. 122.5 min, p = 0.004), no significant differences were observed in warm ischemia time, estimated blood loss, changes in eGFR. Twenty-seven patients (3.0%) had tumor progression, including 8 (0.9%) recurrence, 19 (2.1%) metastasis, and 9 (1.0%) death. CONCLUSION: Retroperitoneal approach for RAPN has confirmed acceptable intra- and postoperative outcomes and suits for renal tumors of all different locations. Large tumor size and obesity are not contraindications for rRAPN.