Six existing minimally invasive techniques for the treatment of primary and secondary malignant hepatic tumors--radio-frequency ablation, microwave ablation, laser ablation, cryoablation, ethanol ablation, and chemoembolization--are reviewed and debated by noted authorities from six institutions from around the world. All of the authors currently believe that surgery remains the treatment of choice for patients with resectable hepatic tumors. However, the clinical results of each of the minimally invasive techniques presented have exceeded those obtained with conventional chemotherapy or radiation therapy. Thus, for nonsurgical patients, these techniques are becoming standard independent or adjuvant therapies. In addition, with continued improvement in technology and increasing clinical experience, one or more of these minimally invasive techniques may soon challenge surgical resection as the treatment of choice for patients with limited hepatic tumor.

Survival after resection and radiofrequency ablation of solitary colorectal liver metastases was comparable. The latter is less invasive and requires either an overnight stay or day-case facilities only.

Radiofrequency ablation (RFA) provides an effective technique for minimally invasive tissue destruction. An alternating current delivered via a needle electrode causes localised ionic agitation and frictional heating of the tissue around the needle. Image-guided, percutaneous ablation techniques have been developed in most parts of the body, but the most widely accepted applications are for the treatment of hepatocellular carcinoma (HCC) in early cirrhosis, limited but inoperable colorectal liver metastases, inoperable renal cell carcinoma and inoperable primary or secondary lung tumours. The procedures are well tolerated and the complication rates low. Patients with coexistent morbidity who are not suitable for surgery are often able to undergo RFA. Most treatments in the lung, kidney and for HCC are performed under conscious sedation with an overnight hospital stay or as a day-case. Larger more complicated ablations, for example, in hepatic metastases may require general anaesthesia. Limitations of RFA include the volume of tissue that can be ablated in a timely fashion, that is, most centres will treat 3 -5 tumours up to 4 -5 cms in diameter. Early series reporting technical success and complications are available for lung and renal ablation. Liver ablation is better established and 5-year survival figures are available from several centres. In patients with limited but inoperable colorectal metastases, the 5-year survival ranges from 26 to 30% and for HCC it is just under 50%. In summary, RFA provides the opportunity for localised tissue destruction of limited volumes of tumour; it can be offered to nonsurgical candidates and used in conjunction with systemic therapy. British Journal of Cancer (2005) Image guided ablation dates to 1989 when the first US guided interstitial laser treatments were performed in liver metastases and the first percutaneous ethanol injections were reported for the treatment of small hepatocellular carcinoma (HCC). Rapid technological developments have resulted in the development of a number of ablative techniques, higher power generators and a range of different electrode designs. Current designs permit ablation of much larger volumes of tissue than was originally possible. Radiofrequency ablation (RFA) has been used in a wide range of locations and applications including adrenal metastases, primary colorectal cancer recurrence and malignant pelvic or paraaortic lymphadenopathy , but in this article we will consider the main areas where RFA has proven effective or is likely to do so.

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