Cryoablation is a minimally invasive technique that has shown promise in patients with non-small cell lung cancer (NSCLC), as well as in those with a limited number of small pulmonary metastases. Cryoablation is limited to situations in which surgical resection is not an option due to advanced age and/or coexistent medical morbidities.
Other treatment options in these settings include external beam radiation therapy (RT), stereotactic body radiotherapy, or radiofrequency ablation (RFA). These approaches may result in clinically useful symptom palliation and improvements in survival. However, not all patients have access to these treatments and many may not be candidates due to medical comorbidities. (See "Radiofrequency ablation of lung tumors" and "Radiation therapy techniques in cancer treatment", section on 'Stereotactic RT techniques'.)
The mechanisms of cellular cytotoxicity, the techniques of cryoablation therapy, and the early results with this technique are reviewed here. The management of patients with early stage NSCLC and the role of surgery in patients with lung metastases are discussed elsewhere. (See "Management of stage I and stage II non-small cell lung cancer" and "Surgical resection of pulmonary metastases: Outcomes by histology" and "Surgical resection of pulmonary metastases: Benefits; indications; preoperative evaluation and techniques".)
MECHANISMS OF CYTOTOXICITY
The mechanisms of cellular destruction caused by cryotherapy include direct effects on tumor cells and indirect effects on tumor vasculature, both of which can contribute to coagulative necrosis in a tumor .
●When tissue is cooled rapidly, water cannot move out of the cell and there is intracellular ice formation, leading to further intracellular cooling and disruption of enzyme and cell membrane functions. If the temperature is kept low for a period of time, additional crystallization results, further damaging the cell.