Local Recurrence After Microwave Ablation of Lung Malignancies: A Systematic Review

Background: Microwave ablation is a therapeutic option for patients with lung malignancies who are not surgical candidates. However, reports on local recurrence have been limited to small case series or retrospective reports. This review was conducted to synthesize the evidence regarding local recurrence and adverse events after microwave ablation for primary non–small cell lung cancer or pulmonary metastases. Methods: The PubMed, Embase, and Scopus databases were searched to identify peer-reviewed studies investigating microwave ablation of lung malignancies with local recurrence or adverse events as a primary outcome. Articles were appraised using the Critical Appraisal Skills Programme criteria. Results: Twelve studies met the eligibility criteria, representing 985 patients and 1,336 treated lung nodules. Studies were limited by infrequent reporting of censoring and by short follow-up. Estimates of local recurrence by the end of the study varied substantially, from 9% to 37%. Tumor size was consistently shown to increase the risk of local recurrence. Among four studies that stratified results by tumor size, local recurrence among tumors smaller than 3 to 4 cm was 5% to 19%. Studies with accrual after 2011 showed recurrence rates between 9% and 26%, whereas earlier studies showed recurrence rates between 22% and 37%. The most common complication was pneumothorax, with grade III or higher complications infrequently encountered. Conclusions: Microwave ablation of primary and secondary lung malignancies is a reasonable therapeutic approach for select patients. Estimates of local failure after treatment are highly variable, with newer reports and smaller tumors having more favorable treatment efficacy rates.