The Emerging Role of Percutaneous Thermal Ablation in the Treatment of Thoracic Malignancies: A Review.

Thoracic malignancies pose a significant public health burden in the United States, with primary lung cancer accounting for nearly 25% of cancer deaths each year. Percutaneous thermal ablation (PTA) for the treatment of lung cancer has evolved from a novel oncologic strategy in the 1970s, to a limited therapeutic option in select patients through the early 2000s, into its current rapidly expanding role as an adjunct therapy, or even standalone treatment, for a diverse group of thoracic malignancies in patients with both localized and disseminated disease. Radiofrequency ablation (RFA) benefits from the largest clinical dataset and greater user experience, but its utility has been limited by a suboptimal heating mechanism in the setting of poor thermal conductive properties within the lung. As the limitations of RFA have come into sharper focus, microwave ablation (MWA) has emerged as a potentially superior ablation technique due to its ease of use and improved heating profile, allowing for larger ablation zones with reduced treatment times. Cryoablation shares many of the technical features of MWA, while targeting cancer cells via pressurized argon gas to induce cryodestruction of target tissue. In clinical practice, the need for at least two cryoprobes and prolonged freeze-thaw protocols adds to procedural time and complexity. To date, there is considerable evidence supporting the safety, tolerability, and efficacy of these minimally invasive modalities, which have been shown to be cost effective and can often be performed on an outpatient basis. Clinical outcomes continue to improve as more data is acquired for each modality, enabling clinicians to refine patient selection and tailor follow-up protocols to better reflect expected post-procedural imaging findings and potential complications. At present, combined multi-modality therapy is an exciting area of active investigation, particularly in cryoablation due to an apparent synergism with established immunotherapies. Recent data suggests PTA may also be useful in more aggressive malignancies, such as advanced NSCLC and small cell lung cancer. Looking forward, PTA remains well positioned to be a valuable therapeutic option in the treatment of patients with lung cancer.