Thermal Ablation for Small Renal Masses: Identifying Anthropometric Factors for Predicting Perioperative and Oncological Outcomes

Percutaneous thermal ablation has been proposed as an effective minimally invasive alternative to surgical treatment. However, proper patient selection is a key factor for optimizing perioperative outcomes. We analyzed a large cohort of patients with T1a-b kidney cancer treated with radiofrequency or microwave thermal ablation. Higher skin to tumor distance confers an increased risk of incomplete ablation. Higher perirenal fat thickness confers an increased risk of CLAVIEN-DINDO >= 3 complications. Objectives: To test for specific anthropometric parameters to predict perioperative outcomes after thermal ablation (TA) for renal cell carcinoma (RCC). Materials and methods: Retrospective single center (2008-2022) analysis of 538 T1a-b RCC patients treated with TA. We tested for specific anthropometric parameters, namely skin to tumor distance (STTD), perirenal fat thickness (PFT), median psoas muscle axial area (PMAA) and median paravertebral muscle axial area (PVMAA), to predict TRIFECTA achievement: (1) absence of CLAVIEN-DINDO >= 3 complications; (2) complete ablation; (3) absence of >= 30% decrease in eGFR. Univariable (ULRM) and multivariable logistic regression models (MLRM) were used for testing TRIFECTA achievement. Results: Overall, 103 patients (19%) did not achieve TRIFECTA. Of all anthropometric factors, only lower PMAA was associated with no TRIFECTA achievement (10 vs. 11 cm(2), P = .02). However, ULRMs and MLRMs did not confirmed the aforementioned association. We than tested for the 3 specific TRIFECTA items. In separate ULRM and MLRM predicting incomplete ablation, both continuously coded STTD (Odds Ratio [OR]: 1.02; CI: 1.01-1.03; P = .02) and STTD strata (STTD > 10 cm; OR: 2.1; CI: 1.1-4.1; P = .03) achieved independent predictor status. Conversely, in separate ULRM and MLRM predicting CLAVIEN-DINDO >= 3 complications, both continuously coded PFT (OR: 1.04; CI: 1.01-1.07; P = .01) and PFT strata (PFT >= 14 mm; OR: 3.3; CI: 1.6-10.2; P = .003) achieved independent predictor status. Last, none of the anthropometric parameters were associated with eGFR decrease >= 30%. Conclusion: None of the tested anthropometric parameters predicted TRIFECTA achievement. However, when the 3 specific TRIFECTA items were tested, STTD and PFT were associated with, respectively, incomplete ablation and CLAVIEN-DINDO >= 3 complications.