Outcomes of cryoablation across PADUA complexity strata for renal tumors: a tertiary-center experience

Surgery is the standard treatment for small renal masses, and cryoablation is an ablative alternative that has been shown to benefit T1a and select T1b patients. However, few studies have analyzed outcomes in renal tumors of varying anatomical complexity. This study aimed to compare cryoablation outcomes across levels of complexity and to determine risk factors for residual tumor. This retrospective cohort study reviewed patients who received cryoablation for localized renal tumor at a single tertiary center between July 2008 and December 2021. The PADUA nephrometry score divided patients into Group A (PADUA 6–9) and Group B (PADUA ≥ 10). Residual tumor was defined as enhancing tissue in the ablation zone on the first contrast-enhanced computed tomography, three months after cryoablation. Treatment parameters and outcomes were compared, and logistic regression was used to determine risk factors for residual tumor. Sixty-nine consecutive patients with localized malignant renal tumors were evaluated; 26 had PADUA 6–9 and 43 had PADUA ≥ 10. Median tumor size was 4.1 cm, 36 patients (52.2%) had tumors > 4 cm, and 43.5% had ASA scores ≥ 3. Nine patients (13.0%) needed cryoablation-related blood transfusion and five (7.2%) had Clavien–Dindo ≥ Gr. 3 complications; renal function did not change significantly. Residual tumor was found in 20 patients (29.0%), giving a primary technique efficacy of 71.0%, and Group A had less residual tumor than Group B (11.5% vs. 39.5%, p = 0.015). Efficacy was 90.9% for tumors 4 cm or smaller versus 52.8% for larger tumors ( p < 0.001). Tumor size was the only independent risk factor (odds ratio 1.70, p = 0.041). Median follow-up was 34.5 months, 5-year overall survival was 90.6%, and no disease-related mortality occurred. The risk of residual tumor increases with anatomical complexity, with tumor size the dominant determinant. Cryoablation was safe and effective in tumors of low complexity; however, a residual tumor rate of 39.5% with PADUA ≥ 10 indicates limited oncological efficacy in complex tumors. Cryoablation therefore remains a valuable option for patients with comorbidity and a small renal mass, whereas larger or more complex tumors require careful counseling and close imaging follow-up. Not Applicable.