Volumetric and functional outcomes at 1-year between percutaneous-ablation and partial-nephrectomy for T1b renal tumors

Introduction. - Indication for percutaneous-ablation (PA) is gradually expanding to renal tumors T1b (4-7 cm). Few data exist on the alteration of renal functional volume (RFV) post-PA. Yet, it is a surrogate marker of post partial-nephrectomy (PN) glomerular filtration rate (GFR) impairment. The objective was to compare RFV and GFR at 1-year post-PN or PA, in this T1b population.Methods. - Patients with unifocal renal tumor >= 4 cm treated between 2014 and 2019 were included. Tumor, homolateral (RFVh), contralateral RFV, and total volumes were assessed by manual segmentation (3D Slicer) before and at 1 year of treatment, as was GFR. The loss of RFV, contralateral hypertrophy, and preservation of GFR were compared between both groups (PN vs. PA).Results. - 144 patients were included (87PN, 57PA). Preoperatively, PA group was older (74 vs. 59 years; P < 0.0001), had more impaired GFR (73 vs. 85 mL/min; P = 0.0026) and smaller tumor volume(31.1 vs. 55.9 cm(3); P = 0.0007) compared to PN group. At 1 year, the PN group had significantly more homolateral RFV loss (-19 vs. -14%; P = 0.002), and contralateral compensatory hypertrophy (+4% vs. +1,8%; P = 0.02, respectively). Total-RFV loss was similar between both (-21.7 vs. -19 cm(3); P = 0.07). GFR preservation was better in the PN group (95.9 vs. 90.7%; P = 0.03). In multivariate analysis, age and tumor size were associated with loss of RFVh.Conclusion. - For renal tumors T1b, PN is associated with superior compensatory hypertro-phy compared with PA, compensating for the higher RFVh loss, resulting in similar Delta RFV-total between both groups. The superior post-PN GFR preservation suggests that the preserved quantitative RFV factor is insufficient. Therefore, the underlying quality of the parenchyma would play a major role in postoperative GFR.(c) 2023 Elsevier Masson SAS. All rights reserved.