vol.30 Department of Radiation Oncology

With the evolution of technology, SRS, which was initially an auxiliary treatment for WBRT, has independently been conducted. Professor Aoyama has taken the lead in conducting multi‐institutional clinical trials and clarified the effect of treating metastatic brain tumors with SRS alone. After the research results were published in 2006 in JAMA (Journal of the American Medical Association), which is one of the world’s top medical journals, treatment with SRS alone became the global standard.

One of the reasons why treatment with SRS alone became the global standard is that cognitive decline was pointed out as a late effect of WBRT. However, with the widespread use of SRS alone, the frequent recurrence of intracranial tumors became a problem.

Then, to search an irradiation method that does not cause cognitive decline and does not interfere with recurrence control, Professor Aoyama started to create an international common language (index) for quantitatively evaluating cognitive function in 2008.

He collaborated with the Department of Psychiatry to create a Japanese version of the cognitive function test used in the United States. At Niigata University, where he took the post of professor in 2010, he started research on the international standard cognitive function evaluation index and therapeutic efficacy in collaboration with the US-led research group RANO (Response Assessment in Neuro-Oncology) and completed the evaluation index in 2019.

As a result of research, Professor Aoyama says, “It cannot be said that cognitive decline is caused solely by WBRT. Patients with a poor performance status develop cognitive decline naturally. If the tumor in the head is not controlled, it will also impair cognitive function, so tumor control is also important.”

Professor Aoyama also started studying a method of combining SRS, which intensively applies pinpoint radiation to patients with metastatic brain tumors, and WBRT, which applies radiation widely and thinly, and in 2015, he revealed in JAMA Oncology that there is a group of patients whose survival rate may increase by adding WBRT to SRS (Figure 1).

“The appeal of radiotherapy is that it can be performed without cutting the affected area, which means less burden on patients. Once the standard treatment is decided, it can be applied to most patients, so there is no difference in treatment between individual doctors,” Professor Aoyama says. “As a result, the overall level of treatment is increased. It is possible to run a simulation before treatment, which is another advantage. We make several treatment plans and select the best one from them. It may be encouraging for doctors who are not good at making prompt decisions to have time for confirmation as a step before irradiation. The appeal of radiology in terms of research is that it involves all organs. From the perspective of radiotherapy, we can smoothly enter research in any area.”

“‘Study more’ is a common phrase for students,” Professor Aoyama says with a laugh. “I feel that there are many aspects of radiology that are not understood by medical students. Compared with Europe and the United States, where there are many radiotherapy facilities and therapists, in Japan, there are fewer medical staff members engaged in radiotherapy although capital investment is made. As a result, radiotherapy tends to become dysfunctional in Japan. Most of the current issues in radiotherapy can be solved if there are ‘people.’ I consider that the gateway to human resource development is to show medical students the appeal of radiology. The aim is a department chosen by students and residents for its future potential, where they can make a leap forward.”