Comparison of Surgical Outcomes Between Enucleation and Standard Resection in Robot-Assisted Partial Nephrectomy for Completely Endophytic Renal Tumors Through a 1:1 Propensity Score-Matched Analysis.

Robot-assisted laparoscopic partial nephrectomy (RAPN) for completely endophytic renal tumors is challenging because of the tumor complexity. The enucleation technique is an ideal resection method to maximally preserve the renal parenchyma. In the present study, we investigated the surgical outcomes of RAPN for completely endophytic renal tumors and compared them between the enucleation and standard resection techniques. One hundred and forty-four patients who underwent RAPN for completely endophytic tumors were the subjects of this study. The subjects were divided into two groups according to the Surface-Intermediate-Base margin score (SIB score): the enucleation group (SIB score 0-2) and the standard resection group (SIB score 3-5). To minimize selection bias between the two surgical methods, patient variables such as age, sex, body mass index, American Society of Anesthesiologists score, tumor size, RENAL nephrometry score (RENAL NS), and preoperative renal function were adjusted using 1:1 propensity score matching. Of the 144 patients, 72 were assigned to the enucleation group and 72 to the standard resection group. After matching, 45 patients were included in each group. The mean tumor size was 26-27 mm and the mean RENAL NS was 9.0-9.1, after matching. The enucleation group showed significantly better preservation of the estimated glomerular filtration rate in the early postoperative period (-4.9% -16%,  = 0.0005) and at 6-12 months after surgery (-4.9% -9.2%,  = 0.0327) than the standard resection group. In addition, a shorter operation time (140 167 minutes,  = 0.0028) was observed in the enucleation group. Other outcomes, including estimated blood loss, positive surgical margin rate, incidence rate of complications, and length of hospital stay, were not significantly different between the two groups. The enucleation technique showed better surgical outcomes for completely endophytic renal tumors in terms of preservation of renal function and operation time than the standard resection technique.