38 - Utilization and Safety of Thermal Ablation Compared to Surgical Resection in T1bN0M0 Renal Cell Carcinoma: A Population-based National Cancer Database Analysis

Purpose: To evaluate the utilization, patient selection, and outcomes of thermal ablation (TA) versus partial nephrectomy (PN) and radical nephrectomy (RN) in patients with T1bN0M0 renal cell carcinoma (RCC).

Materials and Methods: Patients with T1bN0M0 RCC (2004–2022) were identified from the National Cancer Database (NCDB). Baseline variables for TA, PN, and RN patients included age, sex, Charlson-Deyo comorbidity score, tumor size, treatment facility, and socioeconomic factors. Trends in TA utilization, survival, and comorbidity burden were analyzed across five-time intervals: 2004–2006, 2007–2010, 2011–2014, 2015–2018, 2019-2022. Perioperative 90-day mortality and long-term (5- and 15-year) overall survival (OS) of TA were compared to nephrectomy using Kaplan–Meier analysis after one-to-one propensity score matching.

Results: Between 2004 and 2022, TA for clinical T1bN0M0 RCC increased from < 1% in 2004 to 3.03% in 2022 (p< 0.001). The proportion of TA-treated patients with a Charlson-Deyo comorbidity score ≥2 rose from 4.4% in 2004-2006 to 32.9% in 2019-2022 (p< 0.0001), reflecting expanded use in medically complex populations. Despite use in higher-risk patients, perioperative safety of TA remained favorable, with 90- day mortality comparable with PN and RN at < 3% (PN vs TA: p=0.15; RN vs TA: p=0.35). Long-term survival remained highest with surgical resection, as both PN and RN demonstrated significantly higher 15-year OS compared to TA in propensity matched cohorts (PN vs TA: p=0.001; RN vs TA: p=0.03), with median OS of 106 months vs. 91 months (p=0.001) for PN vs TA, and 91 months vs. 81 months (p=0.001) for RN vs TA, respectively. However, survival among TA patients continued to improve over time despite increased baseline risk. Five-year OS for TA in T1b RCC increased from 53.8% in 2004-2006 to 63.5% in 2019-2022 (p = 0.013) suggesting both technical advancements and rising confidence in TA as a viable therapeutic option.

Conclusion: Thermal ablation is increasingly adopted for higher-risk T1b RCC patients, with improving 5-year OS rates since 2004. These findings underscore its evolving role as a safe, effective, and minimally invasive nephron-sparing treatment option. Prospective randomized controlled studies are warranted to confirm these findings.