The standard way of treating liver metastases is surgery, however it cannot be used when the tumours is regarded to be nonresectable. In these cases other options must be considered.  These are  often palliative rather than curative treatment modalities. One of the way to control the liver metastases  is a procedure using very low temperatures to freeze the tumour called cryosurgery also referred to as cryotherapy, cryonic surgery or cryoablation. This technique does not involve invasive surgery. Cryosurgery utilizes extremely cold temperatures to destroy cancerous cells. These extreme temperatures cause cellular damage and  consequently death. This technoque has been increasingly employed for the treatment of primary as well as secondary (metastatic) liver tumours. 

How is the procedure performed?

Before the procedure either local or general anesthesia is administered. During the surgery a metal probe is inserted through the skin and placed into the center of a tumour. This probe releases extremely cold gas - liquid nitrogen or argon which flows through the freezing probe and initiates creation of an ice ball in the center of the tumour which gradually expands outwards. When the ice ball overlaps the margins of the tumour by one centimeter, the tumour tissue is destroyed with  minimal impact on the normal liver tissue.

Clinical and laboratory research suggests that hepatic cryosurgery is effective in the treatment of resectable as well as nonresectable liver metastatic cancer. As cryosurgery is a relatively new treatment the clinical trials are still undergoing. Some studies state that this modality can be used paliativelly rather than as a curative treatment. On the other hand other studies suggest that it is a curative treatment modality for metastatic liver cancer and these even state that the curative effects are significantly higher in patients treated with cryosurgery than in patients treated with conventional surgical techniques for metastatic liver tumours.

Cryosurgery can be applied to tumours in any hepatic distribution. Cryosurgery also increases the number of lesions that may be treated. Whereas a surgeon will seldom resect more than 3 or 4 lesions, cryosugery can be safely applied to as many as 5 or, rarely, even up to 8 lesions. The procedure is limited only by the total volume of liver destroyed and by proximity to critical structures. Unfortunately, as with any focal therapy, the likelihood of long-term benefit declines with a greater number of lesions.

Cryosurgery may also effectively treat lesions in difficult surgical locations, such as adjacent to major vessels. Small lesions (of less than 3 cm) are easier to treat than larger lesions, but even lesions as large as 8 cm are reported to have been completely eradicated. As a result, cryosurgery expands the group of patients who may benefit from a local procedure with curative intent, which is its primary attraction as an adjunctive treatment  to conventional surgery.

Despite the efficacy of cryosurgery, patients have not widely realized its benefit. The procedure is limited by both the technical and professional resources required. There is a particular need for cooperative professional participation because of the diverse skill sets required. Cryosurgery is a major surgical procedure, but it depends fundamentally on sophisticated real-time imaging guidance and monitoring, capabilities that are uncommon in most operating theatres. Interventional radiologists are specifically competent in this aspect of the procedure and can do much to advance its success and application. It is noteworthy that the single greatest advance for cryosurgery has been intra-operative ultrasonography (IOUS).

The success of cryosurgery is often determined by the preliminary IOUS evaluation, during which the operator identifies and targets all treatable disease. As with conventional surgery, the patient's only hope for survival comes from complete eradication of all lesions. IOUS is used to define the number, location and size of all lesions, particularly those that may have been overlooked in pre-operative studies. As well, IOUS defines the relation of lesions to structures that might compromise or complicate therapy, such as major vessels, bile ducts, and adjacent organs.

Cryosurgery, while continuing to evolve, is already an effective therapy and the most successful alternative to conventional surgery for liver cancer. Its potential to provide some patients with long-term benefit should motivate both radiologists and surgeons to consider it in selected cases. While only a minority of our patients will be candidates, this procedure does significantly expand our capability to offer the hope of cure to some patients who otherwise have none. The future of this and other imaging-guided or minimally invasive procedures depends on a close cooperation between surgeons and interventional radiologists - a trend that is believed to be both necessary and inevitable for further development and full realization of these procedures' clinical potential.

Further general information Your doctors and specialist nurses are in an ideal position to give you relevant information on your disease and treatment as they know your individual circumstances. Cancerbackup has a help line (0808 800 1234) and a prize winning video available in English, Italian, Urdu, Bengali, Gujarati & Hindi explaining Radiotherapy & Chemotherapy. Cancernet.co.uk has over 500 pages describing cancer, its management, practical tips and tool which patients, their carers and their doctors have found helpful during the cancer journey.