Survival outcomes following thermal ablation of lung oligometastases categorized by the ESTRO-EORTC classification system.

PURPOSE: To compare outcomes following image-guided percutaneous ablation of lung metastases in patients with oligometastatic disease (OMD) according to categories of the European Society for Radiotherapy and Oncology (ESTRO) European Organisation for Research and Treatment of Cancer (EORTC) classification system. METHODS: This retrospective, bi-institutional cohort study included patients with extrapulmonary primary cancers and up to five extracranial metastases who underwent percutaneous ablation of one or more lung metastases from 4/2015 to 10/2024. OMD categories were defined according to ESTRO-EORTC. Overall survival (OS), progression-free survival (PFS), systemic therapy-free survival (STFS), and therapy-free survival (TFS) were estimated using the Kaplan-Meier method. Tumor burden at last follow-up was classified using RECIST1.1. RESULTS: We included 71 patients (mean age 60.7 ± 17.2 years, 37% male) who underwent microwave or cryoablation of 98 lung metastases in 96 sessions. We classified 37 patients (52%) as de-novo OMD and 34 patients (48%) as repeat OMD. Median OS was 67.0 months (95% confidence interval [CI], 42.9-NR), PFS was 19.1 months (95%CI, 14.5-48.1), STFS was 33.1 months (95%CI, 25.2-NR), and TFS was 15.6 months (95%CI, 10.7-30.8). After a median follow-up of 32.6 months (IQR 23.6-41.4), 30% of patients died, 32% had progressive disease, 17% had stable disease, 21% had no evidence of disease, and none had partial response. No significant difference in outcomes between patients with de-novo and repeat OMD was identified. CONCLUSION: No significant differences in OS, PFS, STFS, and TFS were detected between patients with de-novo and repeat OMD. Percutaneous ablation appears to be a promising treatment strategy across OMD groups.