Thermal Ablation for Non-colorectal Liver Metastases

Recent trends and therapeutic efforts to utilize thermal ablation for treating non-colorectal liver metastases are summarized. Thermal ablation, including microwave coagulation therapy and radiofrequency ablation were utilized for the treatment of liver metastases originating from neuroendocrine tumors, gastric cancer, breast cancer, thyroid cancer, pancreatobiliary cancer, etc. Hepatic resection is a first-line therapy for colorectal liver metastases, but not necessarily for non-colorectal liver metastases. In some patients with non-colorectal liver metastases, an important role of thermal ablation is to provide relief from symptoms and to reduce tumor size in combination with pharmacologic treatment. Local recurrence rates after thermal ablation were 6.3% for liver metastases from neuroendocrine tumors, and 14.7% for colorectal liver metastases. Of 3554 lesions treated, including 693 liver metastases, the mortality and morbidity rates were only 0.3% and 7.2%, respectively. Specific complications in using thermal ablation for non-colorectal liver metastases have never been reported. Excellent median survival times of 49 and 59 months were reported after thermal ablation for neuroendocrine and breast cancer liver metastases, respectively. Gastric cancer liver metastases are often accompanied with extrahepatic metastases and have a poor prognosis. However, if treated with hepatic arterial infusion chemotherapy followed by thermal ablation, the median survival time of 16.5 months was favorable. Thermal ablation has shown a therapeutic impact in the treatment of symptomatic liver-only metastases from neuroendocrine tumors, from a small number of metachronous tumors, a small number of gastric cancer liver metastases, especially when treated with hepatic arterial infusion chemotherapy, and in breast cancer liver metastases without visceral extrahepatic disease. Thermal ablation is a safe and effective procedure for selected non-colorectal liver metastases.