E1747. Role of Minimally Invasive Image-Guided Therapies in Stage I Non-Small Cell Lung Cancer: Current Evidence in Literature
Mount Auburn Hospital
University of Toronto
Emory University Hospital
Emory University Hospital
About 15–30% of non-small cell lung cancer (NSCLC) patients are not surgical candidates due to limited cardiopulmonary reserve, advanced age, and other disqualifying comorbidities. This has led to an increased use of minimally invasive therapeutic options for high-risk patients with stage I NSCLC, including image-guided percutaneous ablation and intraarterial therapeutics (IATs).
Educational Goals / Teaching Points
This exhibit aims to discuss minimally invasive image-guided therapies involved in NSCLC as well as current evidence described in literature.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Using CT guidance, probes can be percutaneously inserted through the chest wall, and once an adequate ablative radius is imaged, the ablative therapy of choice (i.e., radiofrequency, microwave, cryoablation) can be administered. Radiofrequency ablation (RFA) involves the delivery of high-frequency electrical alternating current, producing heat and protein denaturation. Microwave ablation stimulates water molecules in tissue, creating heat as well as protein denaturation. Theoretically, microwave ablation can generate higher temperatures in a larger volume in a shorter time than RFA, although results between these ablative therapies are comparable. Cryoablation, unlike the previously discussed modalities, uses argon and helium to freeze tissue in contact with the ablation probes. There are limited studies comparing ablative techniques to more mainstream treatments such as surgical resection and stereotactic beam radiotherapy (SBRT). One study showed significantly higher overall survival in stage I NSCLC patients undergoing surgical resection compared to RFA, whereas another study showed no significant difference across patients receiving resection, cryoablation, and RFA. In select patients, SBRT has been effective as well, with lower local progression rates and increased 5-year survival as compared to RFA; however, there have been similar rates of 3-year local control and survival between SBRT and RFA. In metastatic disease, RFA was shown to have favorable 5-year survival compared to surgical resection. IATs utilizing arterial anatomy to treat blood vessels that supply tumors are commonly used to treat lesions in the liver; however, their application is scarcely described in lung tumors. Typical targets would be the bronchial artery and pulmonary artery, which are catheterized by accessing the femoral artery or vein respectively using fluoroscopic guidance. Once the interventionalist confirms that the correct vessel is selected, embolic beads (bland or drug-eluting) or chemotherapeutics can be infused, providing localized therapy. Unfortunately, these techniques are not very popular, so outcome data are limited.
As patients present with more aggressive disease with more co-morbidities, it becomes paramount that we understand the data between outcomes of surgical and image-guided therapies. More definitive comparison across ablative modalities with surgical and radiotherapeutic options along with further investigation of intra-arterial therapies would help guide more personalized treatment especially for early-stage patients.