Microwave coagulation therapy for liver cancer: laparoscopic microwave coagulation.

Abstract

A microwave coagulator was developed in 1979 by Tabuse.1 Originally, it was invented as a new cautery device designed to reduce the volume of hemorrhage during hepatectomy. Using the same device, Saitsu et al.2 reported intraoperative and laparoscopic microwave coagulation (MC) therapy for hepatocellular carcinoma (HCC) in 1991. Percutaneous MC was then described by Seki et al.3 in 1994, and the use of MC has rapidly spread since that time. MC for HCC was included in medical insurance coverage in Japan in 1996, and it has since been employed percutaneously, endoscopically (laparoscopy, thoracoscopy), and in open surgery. However, as it has been only 4 years since MC became covered by insurance (and, thus, used widely) in Japan, its clinical value has not yet been established. A representative local therapy for HCC before the advent of MC was percutaneous ethanol injection therapy (PEI), which was introduced around 1983.4,5 Although controversy still continues, there is a general consensus that the results of PEI are comparable to those of surgical resection for HCCs 20mm or less in diameter. Recently, radiofrequency coagulators developed in the United States have been introduced to Japan, and a number of facilities are performing radiofrequency ablation (RA).6–13 The appearance of newer RA devices makes the future position of MC unclear. In particular, as the procedure used for percutaneous MC, which is the most widely performed modality, varies among facilities, and as the criteria for evaluation of its efficacy also differ slightly among facilities, the situation is rather confusing. If the methods differ, the results will also be different. Differences in the approach to cancer are expected to further widen the differences in the results obtained. In this article, we summarize the characteristics and procedures of MC, and review the advantages and disadvantages of MC that have been documented to date, in terms of the approach to cancer. Problems experienced with MC are considered to be similar to those experienced with RA.