Cryosurgery for colorectal liver metastases

Destructive therapy for liver tumors has been available for some time and a number of options have been used. These include alcohol injection, heating therapy with laser and, more recently, radiofrequency ablation and cryosurgery. The principle of cryosurgery is to destroy tissue by freezing and causing expansion of intracellular water. The effect of this treatment is to cause disruption of the cell membrane as the ice expands, thereby killing the cells and, secondly, releasing intracellular antigen into the circulation to promote an immune response. Lastly, there is a "frostbite" effect with thrombophlebitis of vessels feeding the tumor because of the freezing. A number of trials have evaluated destructive therapy, but none have shown definite benefit over chemotherapy alone. This review examines the data as it currently stands.