Microwave Ablation of Refractory Oligometastatic Non-Small Cell Lung Cancer in the Liver

PURPOSE:: To evaluate safety and effectiveness of microwave ablation (MWA) in the treatment of liver metastases (LM) secondary to non-small cell lung cancer (NSCLC). MATERIALS AND METHODS:: This retrospective study included patients with NSCLC who underwent MWA of LM from 3/2015 to 7/ 2022. Local tumor progression-free survival (LTPFS) and overall survival (OS) were estimated using competing risk analysis and the Kaplan-Meier method. Post-procedural adverse events were recorded according to the Common Terminology Criteria for Adverse Events (CTCAE) v5.0. RESULTS:: Twenty-three patients with 32 LM were treated in 27 MWA sessions. The dimension of the largest index tumor was 1.96 ± 0.75 cm (mean ± SD). Technical success was 100%. Technical efficacy was achieved in 26/32 tumors (81.3%). Median length of follow-up was 37.7 months (IQR: 20.5-54.5). Median LTPFS was 16.3 months (95% CI: 7.87-44.10). Median OS was 31.7 months (95% CI: 11.1 to 65.8 months). Ablation margin was a significant factor for LTPFS, with tumors ablated without a measurable margin being more likely to progress compared to those with measurable margins (Subdistribution hazard ratios [SHR] 0.008-0.024, p<0.001). Older age (HR:1.18, 95%CI:1.09-1.28, p< 0.001) and presence of synchronous lung metastases (HR:14.73, 95%CI: 1.86-116.95, p = 0.011) were significant predictors of OS. Serious adverse events (CTCAE grade ≥3) within 30 days occurred in 2/27 sessions (7.4%), including pulmonary embolus and severe abdominal pain. CONCLUSION:: Percutaneous MWA is a safe treatment for NSCLC LM, with longer survival seen in younger patients and those without synchronous lung tumors.