It's been five years since radiation therapy was introduced to Korean pet clinical practice. The number of animal hospitals with radiotherapy machines has increased to five, and the field has grown to the point that a separate conference has been organized.
The demand for radiation therapy for petcancer patients has also grown. The machines are running nonstop, and thedemand is so high that new patients are limited per week. In the future, petradiation therapy is expected to become more efficient as precision medicineand artificial intelligence (AI) are introduced.
As the first movers are still establishingthemselves, it is pointed out that the safety and quality assurance ofradiotherapy and the strengthening of medical physics capabilities should besolidified.
The Korean Veterinary Radiology Society(President Choi Soo-young) held the first Veterinary Radiation OncologyConference on Sunday, December 1, at the headquarters of Yoohan in Seoul. Morethan 150 participants gathered and showed great interest in the inauguralconference.
At the conference, Prof. Shin Kyung-Hwan,Department of Radiation Oncology, Seoul National University Hospital, and Prof.Choi Chang-Heon, Department of Radiation Physics, Seoul National University Hospital, gave special lectures on the overall understanding of radiation therapy and the role of radiation physics.
Professors Hwang Tae-Sung (Gyeongsang National University), Choi Ji-Hye (Seoul National University), and Kim Jae-Hwan(Konkuk University) presented radiotherapy for various tumors, including nasal tumors, bone tumors, and brain tumors.
Dr. Park Jung-Soo of the Seoul Animal Imaging Tumor Center and Dr. Choi Moon-young of the S Animal Cancer Center presented cases of radiotherapy for feline thymoma and vascular invasive adrenal tumors.
“It has been five years since the introduction of veterinary radiotherapy in Korea, and it has been applied to many pet tumor patients,” said Prof. Tae-Sung Hwang, head of the Radiation Oncology Division of the Korean Veterinary Radiology Society. ”The need to understand radiation oncology and discuss its effectiveness, prognosis, and safety has also increased, so we organized this conference to share academic discussions and practical clinical experiences.”
Major cancer treatment options along with surgery and chemotherapy Improving quality of life with long-term preservation treatment
Conventional radiation therapy machines,including those used in animals, are linear accelerators. They accelerate electrons and irradiate the targeted area (cancerous tissue) with radiation. Inhuman medicine, protons and even heavy particles are utilized, which are suitable for hitting only the deep target area and reducing side effects in the surrounding area compared to electrons.
The radiation from the radiotherapy machine destroys the DNA of cancer cells. This process requires oxygen, which is why cancerous tissue with a good blood supply are more sensitive.
Radiation therapy is based on fractionated treatment. This means that the irradiation is repeated in several sessions.This is done to maximize the destruction of cancerous tissue while reducing side effects.
“As medical devices improve and clinical research continues, the number of fractions is gradually decreasing while the effectiveness of treatment is increasing,” said Prof. Shin Kyung-Hwan of the Department of Radiation Oncology at Seoul National University Hospital, who opened the conference. In animals, the number of fractions is more of an issue as general anesthesia is required for each radiation treatment.
Radiation therapy is one of the main weapons in cancer treatment, along with surgical resection and chemotherapy. In humans, it is so common that as of 2019, about 30% of the 250,000 cancer patients diagnosed annually in Korea received radiation therapy.
Prof. Shin points out that radiotherapy isa long-term conservative cancer treatment. It is better in terms of return tosociety and quality of life after cancer treatment.
For example, for tumors in the bladder,rectum, or anus, resection of the cancerous tissue and surrounding area risks leaving severe impairment of urination and defecation. Instead of surgery,radiation therapy is more suitable. This is also true in animals. Tumors in the perianal area or bladder are one of the main targets for radiation therapy in pets.
5 animal hospitals that offer radiation therapy
Radical treatment is the main focus...but palliative use is on the rise
In 2019, Seoul Animal Imaging and Tumor Center became the first animal hospitals in Korea to introduce a radiation therapy machine. The following year, in 2020, the S Animal Cancer Center followed suit, and in 2022, Seoul National University Animal Hospital.
Since then, the number of animal hospitals offering radiation therapy has increased to five, including the Royal Animal Medical Center and the VIP Animal Cancer Center. All four radiotherapy machines are megavoltage machines, except for the VIP Animal Cancer Center, which uses orthovoltage machines.
Radiation therapy in animals also utilizes intensity-modulated radiation therapy (IMRT) to reduce side effects. IMRT is a method of subdividing the radiation field by considering the location of tumor tissue and surrounding normal tissue, and adjusting the intensity of the radiation in each subdivided area. This allows for sufficient radiation to be delivered to the target (tumor tissue) while reducing the amount of radiation to surrounding tissues as much as possible.
“The popularity of radiotherapy in animal hospitals practice in Korea has expanded a lot in the past five years,” said Dr. Heo Chan, director of the S Animal Cancer Center. ”In the beginning, we had to do a lot of convincing, but now owners come to us with the assumption that radiotherapy is one of the options for cancer treatment.”
Prof. Choi Ji-hye, a professor in charge of radiotherapy at Seoul National University Animal Hospital, also said the demand for radiotherapy is high. The number of anesthesia cases for radiotherapy alone has increased significantly.
“In animals, radiotherapy will be mainly a radical treatment that directly irradiates cancerous tissues,” says Prof. Shin Kyung-Hwan. When the tumor is localized and there is no distant metastasis,'radical therapy' is a form of treatment that attempts to cure the disease.
Radiation therapy can also be utilized for palliative purposes in situations where radical treatment is not possible. Even in situations where it is difficult to completely eliminate cancer, reducing pain caused by bone metastases or inflammation caused by cancer with radiotherapy can greatly improve the quality of life of terminally ill patients, and the satisfaction of their caregivers is very high.
Prof. Choi Ji-hye also said that while radical treatment is usually tried, palliative treatment is sometimes implemented after explaining and agreeing with the guardian in cases where there are metastases.
Full-day for a treatment plan and general anesthesia for every treatment... a heavy workload
The Weekly Intake of new patients is limited
Precision medicine and artificial intelligence application hot topics.. Reducing workload and organizing demand traffic
Both centers that provide radiation therapy to pet cancer patients cite physical limitations as a challenge. There are many pet cancer patients, few radiotherapy machines, and formidable workload for each treatment.
It takes a few hours to a day to develop a detailed radiation treatment plan based on imaging diagnostics. The protocol varies depending on the patient, but once started, radiation therapy must be repeated several times in divided treatments. Each treatment requires general anesthesia. The burden on the treatment staff is cumulative.
As a result, both centers limit the number of first-time patients who start radiation therapy to one hand each week.Patient waiting is inevitable.
In this regard, efforts are being made to utilize radiation therapy more efficiently. Precision medicine is being applied to radiotherapy to predict how effective the treatment can be for each individual cancer patient through genetic tests.
This evidence-based prediction could increase the demand for radiotherapy for patients who are expected to benefit from it. Conversely, caregivers who prioritize radiation therapy can be steered to other cancer treatment options.
The workload of individual radiation treatments is also showing signs of change.
When planning a radiation treatment,contouring is essential to clearly delineate the area to be irradiated,delimiting the boundaries of surrounding normal organs, a task that can take hours of manual labor, but which AI can help with. The AI's contours can then be checked by a physician, reducing hours of work to 10 minutes.
In humans, these AI-based automatic contouring programs are actively used in the radiation treatment planning stage. Multicenter studies have reported that AI helps reduce inter-physician variability.
An official from Oncosoft, a company that provides such programs, said at the conference, “If you reduce the workload of treatment planning with the help of AI, you can focus on other parts of radiotherapy.” “In humans, about half of radiotherapy departments are already using AI,” he noted.
In animals, Oncosoft is collaborating with Seoul National University Animal Hospital, S Animal Cancer Center, and Gyeongsang National University College of Veterinary Medicine, and expects to have more concrete results next year.
Quality assurance and safetymanagement...building trust in radiation therapy
At the conference, Dr. Choi Chang-heon, a professor of radiation medicine and physics at Seoul National University Hospital, shed light on the role of radiation physics in radiotherapy. He provided an overview of medical physics knowledge and related regulations that should be considered for radiation safety management.
Prof. Choi Ji-Hye said, “The demand for radiation therapy in pet patients is very high. The quality of life is greatly improved and pet owners are satisfied with the treatment.” However, she emphasized that ‘it is important to do ’radiation therapy well' at this time.”
“It's important to have a comprehensivequality assurance (QA) foundation to ensure that radiation therapy is workingas intended and is safe. Building the medical physics capabilities ofclinicians is also a challenge.
“It's a crucial time as leading groups arepromoting radiotherapy,” he said, ”but we need to go beyond just providingradiotherapy and create a trustworthy foundation. We also need to developinstitutional arrangements to ensure this.”
