Ablative treatments for lung tumors: radiofrequency ablation, stereotactic radiosurgery, and microwave ablation.

RFA and SRS have been demonstrated to be safe with reasonable efficacy in the treatment of small lung tumors. It is unclear which option is the most effective in the treatment of NSCLC, with both RFA and SRS demonstrating similar early response and progression rates. RFA can be performed in one treatment session, whereas it now seems that SRS is more effective if larger doses of radiation over two to three fractions are performed. RFA is not recommended for centrally based tumors. There are also some tumors (eg, small apical tumors, posteriorly positioned tumors close to the diaphragm, and tumors close to the scapula) where it may be difficult percutaneously to position an active electrode. Such patients are more optimally treated with SRS. In certain circumstances, a combined approach may be beneficial (RFA and SRS). At this point in time, MWA is the least well developed modality. Although treatment times and heat-sink effect may be less compared with RFA, larger trials are needed to understand better the impact of this factor on effectiveness and safety. The heat-sink effect may be protective, minimizing the necrosis of large blood vessels and the risk of subsequent fatal hemoptysis. Future studies need to address long-term outcomes using standardized assessments of treatment response between centers. Comparisons between different RFA systems and ablation modalities need to be undertaken to delineate the optimal use of these strategies in the treatment of early stage lung cancer. Until long-term data with these ablative techniques become available, surgical resection should be performed when clinically possible.