Radiotherapy to increase liver cancer survival rateProfessor Jung-Il Yoo, Department of Radiation Oncology, Samsung Medical Center

1. Radiotherapy Research Achievements for Liver Cancer

This study is a cohort of records of patients diagnosed with liver cancer at Samsung Medical Center since 2005 on their underlying liver disease, liver function, tumor status, and treatment options. We wanted to see images of changes in treatment for these patients up to 2017

In total, about 9,100 patients were enrolled in the study. Overall, the cumulative number of patients receiving radiotherapy increased as the time of liver cancer diagnosis increased.

The most noticeable change was the pattern of changes when I received my first radiation therapy to my liver. In 2005, it was performed in almost 1 in 1,000 patients, but in 2017, 13% or 13 out of 100 patients received radiotherapy, and the frequency of use was increasing.

In addition, the most important issue in tumor treatment is the improvement of survival rate. Amazingly, from 2005 to 2017, the five-year survival rate improved from about 55% to more than 75% in 2017.

During this period, it is also observed that the survival rate is lower in patients who use radiotherapy as a primary treatment compared to those who do not use radiotherapy as a primary treatment*. This is believed to be due to the fact that people with very severe illnesses are more likely to use radiotherapy.

*Initial treatment: If it is the first treatment or less than 1 month after treatment is administered.

Rather, I think it is important to see how the results of radiotherapy actually change according to the changing times. If you look at the extent of the survival rate in 2005, it was much lower than that of the radiotherapy group, but in recent years, the results of radiotherapy have improved, and now the area has decreased by almost 1/2.

Of course, this has been possible due to the development of management of the underlying liver and liver function, such as hepatitis, and other treatment methods for tumors, such as surgery. However, early and aggressive radiotherapy is also believed to help improve treatment outcomes.

2. What is radiation therapy?

Radiation therapy is a treatment method that intensively delivers light-like energy to the tumor and uses that energy to destroy the tumor's DNA and trigger an immune response to control the tumor. As I mentioned earlier, these treatment methods are advancing tremendously. In intensity-modulated radiotherapy, radiation exposure is controlled in real time by a type of differential product called a multilobed collimator, which is usually fitted to the radiotherapy device, as opposed to conventional radiotherapy, which delivers the same energy in one direction. When it is irradiated into the human body, the intensity of the radiation is controlled in real time to deliver highly precise radiation.

In addition, proton therapy* has the property of particle rays, which transmit and dissipate most of the energy at a certain depth, whereas ordinary radiation penetrates the human body. Therefore, body disguised radiation therapy, which is known to be the best in general radiation, has a wide effect on the normal liver due to the exposure of the radiation in a sharp way. Proton therapy is a treatment method that is gaining worldwide attention in liver cancer, which can deliver focused radiation and requires good protection of the normal liver.

*Proton therapy: A type of radiation therapy that destroys cancerous tissue by shooting protons at the cancerous site at high speed.

3. Who should receive radiation therapy?

As with other cancers, when the metastatic lesion of the tumor causes certain symptoms, such as pain and bone weakness, radiotherapy has already been performed to relieve the symptoms. So, in a nutshell, radiation therapy may be a good alternative if surgery or radiofrequency therapy is not possible due to the location and age of the tumor and other systemic conditions, as well as relieving the symptoms of metastatic tumors.

In addition, in the case of liver cancer with major vascular infiltration, such as the portal vein, it has been confirmed that radiotherapy can maintain liver function and inhibit metastasis.

4. Why Radiation Therapy Has Gained Attention as an Early Treatment

There are two main ones. One is the rapid development of radiotherapy technology, as I mentioned, and the other is that there are many good clinical studies reporting on radiotherapy for liver cancer.

A clinical study was conducted by Korean researchers to compare the effectiveness of stereotactic body radiotherapy** compared to radiofrequency cauterization*, which is a standard treatment method. In terms of local control, stereotactic body radiotherapy was better overall than radiofrequency therapy, and the difference was even greater when considering tumors and other liver characteristics.

*Radiofrequency cautery: A local treatment method for primary liver cancer or metastatic cancer

**Stereotactic body radiation therapy: A treatment that irradiates tumors in the human body with a large amount of radiation for 1~5 times at a time

In addition, the National Cancer Center of the Korean Liver Cancer Society has proposed liver cancer guidelines again in 2022. Here, we have suggested the possibility that radiotherapy can be applied in various situations as an optimal or alternative treatment. It should be noted that this increased application of radiotherapy for liver cancer and confirmed the potential for improved overall liver cancer treatment outcomes.