凍結療法の現状と展望

Cryotherapy is the latest minimally invasive treatment classified as non-vascular interventional radiology（IVR）. Fine needles are used for percutaneous puncture of tumors under imaging guidance. Using high-pressure argon gas for freezing, the needle tip is brought to an extremely low temperature（-４０℃）or lower, and the tumor cells are frozen and destroyed. The advantages of this treatment are that the freezing range can be confirmed on imaging during the procedure, and pain is less intense during the treatment. Currently, in Japan, cryotherapy for tumors, such as renal cancer, is being performed in fewer than３０hospitals.
Our hospital decided to introduce a cryotherapy device in ２０１６, and preparations for the operation started at the end of ２０１６. In ２０１７, three in-hospital briefings were held, and we also conducted a tour of facilities with installed cryotherapy devices. After this preparation period, the first treatment was performed at the Tokushima Prefecture in March ２０１８. By August ２０１９, cryotherapy had been performed in seven cases of renal cell carcinoma. In all cases, the treatment was completed without serious complications and could be performed during the scheduled hospital stay. At the follow-ups, no residual or recurrent tumors were found after only one treatment.
Currently, only small-diameter renal malignancies are covered by insurance. Therefore, the Japanese Society of Interventional Radiology has submitted a request for the expansion of indications for cryotherapy to the Ministry of Health, Labor and Welfare. In the future, expansion of indications is expected for lung, breast, liver, bone, and soft tissue tumors, and we hope to respond flexibly.