APASL 2020| Prof. Diana Payawal: Which is better, Microwave ablation vs radiofrequency ablation for treatment of liver cancer

In the case of patients with liver cancer who are intolerant to surgical resection, ablation technology is widely used to reduce pain, prolong life cycle and improve quality of life of patients.There are two commonly used ablation techniques, radiofrequency ablation and microwave ablation, which have different characteristics. But how to choose in treatment?Let's listen to professor Diana Payawal, President of the Asian Pacific Association for the Study of the Liver (APASL) 2019 and Professor of SAN Santos Medical Center in Manila, Philippines, speaking to Hepatology Digest during the 29th Annual meeting of the Asian Pacific Association for the Study of the Liver (APASL2020).

<Hepatology Digest>: Microwave ablation and radiofrequency ablation have been widely used in the non-surgical treatment of liver cancer. What are the similarities and differences between the two methods?

 

Dr Payawal: The similarity is that they use heat to ablate the tumor. Most of the liver cancers are soft tumors, so they are sensitive to extremes of temperature, whether that is heating (microwaves and radiofrequency) or cooling (cryotherapy). In our country, we have also used chemical ablation using ethanol. Up until 2000, everyone was doing ethanol injections for liver cancer before practice graduated towards radiofrequency ablation (RFA), which uses thermal therapy and coagulation necrosis to burn the tumor. We find a lot of problems with it because it produces a longitudinal ablation point, has heterogeneous ablation areas so there is viable lesion remaining, and there can be grounding pads which can sometimes cause burns on patients. The ablation time is longer because it is increased gradually. For microwave ablation on the other hand, we can ablate the tumor homogenously in a spherical pattern (and most tumors are spherical in shape). We can ablate faster. We can perform a ten-minute ablation and therapy is done. And there are no grounding pads to potentially cause skin burns. Unlike RFA, there is a wider diameter of ablation with microwave therapy. What are the indications for each technique? For bigger tumors, microwave therapy would actually suffice. If the tumor is next to a blood vessel not involved in the tumor, the heat sink effect does not work, so it can ablate a tumor next to a vessel. Those are the similarities and differences.

<Hepatology Digest>: The management of advanced HCC patients will involve a number of disciplines. Could you introduce your experience in the management of these patients using a multidisciplinary approach?

 

Dr Payawal: I was trained in a center where we do everything. We do endoscopy. We take care of liver cancer patients. We do our own liver biopsies. We do our own ablation therapy. In other countries, they do not have this expertise, so radiology teams actually come in for RFA and microwave procedures, and oncologists come in for oral chemotherapy. This is becoming less of a concern as we are being trained to tackle all aspects of liver disease and management. The emergence of immunotherapies and targeted therapy for liver cancer is of course now drawing a lot of attention as well.

<Hepatology Digest>: The Hepatology Digest audience is Chinese hepatologists, and they cannot be here at the meeting. If you could address them, what words of encouragement would you share with them?

 

Dr Payawal: China has a lot of liver cancer patients. It is a two-way street, whereby we learn from them and they learn from us. We really miss them at APASL, and if they were here, we would be exchanging ideas on what is new and what they are doing in China, and what is new in other South-East Asian countries. We know that the coronavirus will start to decline, and indeed it already is in China. Although there are new cases elsewhere, China appears to have control of its epidemic, and kudos to the Chinese doctors for that. I was so surprised to see that they had constructed a hospital in a couple of weeks. That could only happen in China. So, hats off to the Chinese strategy for controlling the virus. I look forward to seeing our Chinese colleagues active at APASL again joining forces against liver disease. Infection is a big issue. We have just had the Presidential Lecture on bacterial infections, which is a growing concern in clinical practice. We have COVID, hepatitis B and C, and liver cancer as a progression of hepatitis. So this is something we can all work together on.