Cryotherapy has been used clinically in the treatment of metastatic liver malignancies since the 1980s. Rapid freezing to sub-zero temperatures promotes ice formation in the extracellular space and the exit of intracellular water. Cellular death is the result of dehydration, protein denaturation, and microcirculatory failure. Cryotherapy probes use nitrogen or argon gas as a coolant and the development of the ice ball can be monitored using ultrasound, computed tomography, or magnetic resonance imaging. Traditionally, cryotherapy has been performed during laparoscopy or laparotomy, using intraoperative ultrasound for image guidance. A decrease in cryoprobe size (from $ 24 Fr to $ 15 gauge) in conjunction with experience gained in open cryosurgical treatment has allowed the development of minimally invasive percutaneous approaches. In this review, we describe the use of cryotherapy for treatment of primary or secondary liver neoplasms using a percutaneous approach.
KEYWORDS: Liver malignancy, ablation, cryotherapyObjectives: Upon completion of this article, the reader should be able to (1) understand the recent advances in cryotherapy, including the expanding clinical indications, (2) review the techniques currently used for cryotherapy of the liver, and (3) present the results reported in the current literature regarding results and complications of percutaneous cryotherapy. Accreditation: Tufts University School of Medicine (TUSM) is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. Credit: TUSM designates this educational activity for a maximum of 1 Category 1 credit toward the AMA Physicians Recognition Award. Each physician should claim only those credits that he/she actually spent in the activity.Primary and metastatic liver carcinomas have an exceedingly poor prognosis without treatment. For hepatocellular carcinoma (HCC), surgical resection offers the only possible cure. Unfortunately, secondary to multiple reasons such as poor liver reserve, number of metastases, tumor proximity to major vascular or biliary structures, or extrahepatic metastases, only 10% of patients with newly diagnosed HCCs are candidates for resection. Similarly, only 10 to 15% of patients presenting with colorectal liver metastases are candidates for surgical resection.2 Hepatic metastases are the primary cause of death in patients with colorectal cancer.3 Liver metastases are seen in up to 50% of patients with colorectal