Fire or ice - emerging therapies for unresectable pulmonary nodules

Lung cancer and pulmonary metastases remain the leading cause of cancer-related mortality. While surgery is the gold standard, local tissue-ablative therapies are increasingly used in unresectable disease or inoperable patients. Minimally invasive local control presents a safe, repeatable approach to slow disease progression and prolong survival.

Ablative techniques (radiofrequency, microwave, cryoablation, pulsed electric field) utilize extreme heat, cold, or energy to induce cancer cell death. Traditionally, ablation occurred percutaneously with image guidance, but transbronchial approaches are gaining popularity due to a potentially improved complication profile with reduced tumoral seeding. Stereotactic body radiotherapy utilizes non-invasive, precise radiation with a steep dose fall-off to protect peritumoral tissue. Transarterial infusions via transarterial chemoembolization and intraarterial chemoperfusion are emerging approaches that exploit tumor vasculature to provide focal cytotoxicity and ischemia. Intratumoral injectables (chemotherapy, immunotherapy, radiosensitization, oncolytic viruses, adoptive cell therapy, and chimeric antigen receptor T-cell therapy) directly target the tumor microenvironment, potentially increasing efficacy whilst minimizing systemic adverse effects.

In the age of individualized cancer therapy, a multidisciplinary approach with concurrent modalities can achieve local control. This review provides a comprehensive discussion regarding the role and types of local control, safety, efficacy, and survival outcomes in assessing percutaneous, transbronchial, intraarterial, and intratumoral approaches in nonsurgical patients.