Microwave Ablation for Lung Neoplasms: A Retrospective Analysis of Long-Term Results

Purpose: To determine the long-term safety and efficacy of microwave (MW) ablation in the treatment of lung tumors at a single academic medical center. Materials and Methods: Retrospective review was performed of 108 patients (42 female; mean age, 72.5 y +/- 10.3 [standard deviation]) who underwent computed tomography (CT)-guided percutaneous MW ablation for a single lung malignancy. Eighty-two were primary non-small-cell lung cancers and 24 were metastatic tumors (9 colorectal carcinoma, 2 renal-cell carcinoma, 4 sarcoma, 2 lung, and 7 other). Mean maximum tumor diameter was 29.6 mm +/- 17.2. Patient clinical and imaging data were reviewed. Statistical analysis was performed by Kaplan-Meier modeling and logistic regression. Results: Odds of primary technical success were 11.1 times higher for tumors < 3 cm vs those > 3 cm (95% confidence interval [CI], 2.97-41.1; P = .0003). For every millimeter increase in original tumor maximal diameter (OMD), the odds of not attaining success increased by 7% (95% CI, 3%-10%; P = .0002). For every millimeter increase in OMD, the odds of complications increased by 3% (95% CI, 0.1%-5%; P = .04). Median time to tumor recurrence was 62 months (95% CI, 29, upper bound not reached; range, 0.2-96.6 mo). Recurrence rates were estimated at 22%, 36%, and 44% at 1, 2, and 3 years, respectively. Recurrence rates were estimated at 31% at 13 months for tumors > 3 cm and 17% for those < 3 cm. Complications included pneumothorax (32%), unplanned hospital admission (28%), pain (20%), infection (7%), and postablation syndrome (4%). Conclusions: This study further supports the safe and effective use of MW ablation for the treatment of lung tumors.