[Results of percutaneous cryoablation for malignant lung tumors compared with radiotherapy]

Radiotherapy has been regularly applied mainly for inoperable patients with non- small cell lung cancer, and various clinical trials have been performed. On the other hand, we have applied percutaneous cryoablation for lung tumors (PCLT) since 2002. In this paper, we describe our experience of PCLT compared to the results of radiation treatment. Three-year local progression-free rates with stereotactic body radiotherapy were 79-92% in stage I A and 30-79% in stage I B. Those with proton radiotherapy were 82-89% in stage I A and 49-62% in stage I B. CTCAE grade ≥3 complications occurred in 3-28% cases, such as radiation pneumonitis. As for PCLT, 1-, 2- and 3-year local progression-free rates were 80.4%, 69.0% and 67.7%, respectively. Pneumothorax, pleural effusion, and hemoptysis occurred after 61.7%, 70.5%, and 36.8% sessions, respectively. Of all cases with pneumothorax, 17.6% required chest tube insertion and 1.7% required pleurodesis. Delayed and recurrent pneumothorax occurred in 7.8% each. CTCAE grade ≥3 complications occurred in 1.5% cases. The biggest advantage of PCLT compared with radiotherapy is the possibility to treat local recurrence at the same site as treated before. In addition, no radiation pneumonitis occurs in PCLT. Moreover, less space or budget is needed when PCLT is newly introduced in a hospital. Although high reliable clinical data is not achieved yet, PCLT is one of the promising methods in local treatment.