Microwave ablation: initial experience in Brazil

Interventional radiology is a field of medicine that has grown significantly in recent decades. Technological advances, together with increased experience on the part of interventional radiologists as well as their interaction with oncologists and professionals in other medical specialties, have provided an important place for interventional radiology within the therapeutic arsenal for the treatment of neoplastic diseases(1). Within that context, there are thermal ablation techniques such as radiofrequency ablation, cryoablation, and microwave ablation, which are minimally invasive means of treatment involving the insertion of specific needles or image-guided antennae, in order to treat focal lesions. Microwave ablation involves the use of a generator that produces an electromagnetic field, transmitted by an antenna, which causes agitation and friction among water molecules, thus increasing the temperature of the tissue to 60–150°C, resulting in coagulative necrosis(2). Microwave ablation has the following advantages over radiofrequency ablation(3,4): producing higher temperatures, with the ability to ablate larger areas in less time; having less heat sink interference; and being unaffected by the high impedance of certain tissues. This therapeutic modality has been in clinical use since the 1990s(5,6), with exponential increases in its use at various sites, mainly the liver, lung, kidney, and bone. However, its use has been authorized in Brazil only since the end of 2018. The first two cases in which microwave ablation was performed in Brazil, one a case of lung injury and the other a case of liver injury, were both treated in May 2019 at the São Paulo State Cancer Institute. (author)