Robot-assisted partial nephrectomy (RAPN) for completely endophytic renal masses: a single institution experience

Objective To analyse the outcomes of robot-assisted partial nephrectomy (RAPN) for completely endophytic renal tumours. Patients and Methods Medical records of patients who had undergone RAPN for a completely endophytic (i.e. 3 points for the 'E' domain of the R.E.N.A.L. nephrometry score) enhancing renal mass at our Centre from 2006 to 2012 were retrieved from our prospectively maintained RAPN database and used for this analysis. Demographics, surgical and early postoperative outcomes were compared with those of patients with exophytic masses (i.e. 1 point for the 'E' domain) and those of patients with mesophytic masses (i.e. 2 points for the 'E' domain). Results In all, 65 patients (mean age 56 years; mean body mass index 29.4 kg/m(2); mean Charlson comorbidity index 3.2) were included in the study group, accounting for 16.7% of RAPN cases over the study period. The main surgical outcomes were: mean operative time 175 min, mean estimated blood loss 225 mL, and mean warm ischaemia time 21.7 min. Pathology showed a malignant histology in 48 cases (74%), mostly clear cell renal cell carcinoma. Two positive margins (3%) were found. Patients with a completely endophytic mass had smaller tumours on preoperative imaging (mean 2.6 vs 3.3 for mesophytic vs 3.7 cm for exophytic; P < 0.001), and higher overall R.E.N.A.L. score (mean 8.7 vs 7.6 vs 6.4; P < 0.001). There was a lower rate of unclamped cases in the endophytic group (3.1% vs 4.8% vs 18%; P < 0.001). There were no differences in intraoperative complications, length of hospital stay, positive margin rate, postoperative change in estimated glomerular filtration rate, given a similar length of follow-up (mean 12.6 vs 15.7 vs 14.5 months; P = 0.3). Conclusion RAPN for completely intraparenchymal renal tumours can be safely and effectively performed in centres with significant robotic expertise, with surgical outcomes resembling those obtained in the general RAPN population.