Partial nephrectomy for T1b renal masses: comparison of laparoscopic and robot-assisted approach

Objective To compare the operative-postoperative outcomes of laparoscopic and robot-assisted partial nephrectomy (LPN and RAPN) for patients with T1b renal masses. Methods A total of 169 T1b renal mass patients receiving LPN(n=69) or RAPN(n=100) in our center between October 2009 and October 2017 were retrospectively collected. There were 46 males and 23 females in LPN group, with a mean age of (55.0±11.9) years. The mean tumor size was(5.09±0.76)cm, and mean R. E.N.A.L score was 6.36±1.53. 49 procedures (71%) were performed via a retroperitoneal approach in LPN group. There were 59 males and 41 females in RAPN group with a mean age of (52.9±11.7) years. The mean tumor size was(4.95±0.66)cm, and mean R. E.N.A.L score was 8.17±1.50. 31 procedures (31%) were performed via a retroperitoneal approach in RAPN group. There was statistical significance between two groups in R. E.N.A.L score and surgery approach(P< 0.001). The group covariates were balanced through propensity score matching (PSM) using 1∶1 nearest neighbor matching method. After PSM, operating time, estimated blood loss, warm ischemia time, incidence of complications, hospital stay and postoperative follow-up status were compared between LPN(n=36)and RAPN(n=36)group. Results After PSM, patient distributions were closely balanced. In the LPN vs the RAPN group, there were significant different in warm ischemia time[(23.9±7.3)min vs.(20.4±6.7)min, P 0.05], variation of estimated glomerular filtration rate from baseline [(9.97±8.98)% vs.(9.27±9.19)%, P>0.05], positive surgical margin rate (1.4%vs.0, P>0.05) and rate of recurrence or metastasis(1.4% vs. 1.4%, P>0.05) between groups. Conclusion Considering operative, functional and oncologic outcomes, both RAPN and LPN performed by an experienced surgeon were acceptable for patients with T1b renal masses. If available, robotic approach may reduce operative trauma and complications. Key words: Kidney neoplasms; Partial nephrectomy; Robot-assisted laparoscopy; Laparoscopy