[Innovative ‘Heavy Ion Therapy’] Severance Hospital “New Hope for Patients with Intractable Cancer”

‘Heavy ion therapy’ is considered a dream cancer treatment.

The principle of treatment is that a synchrotron accelerates and ionizes carbon atoms close to the speed of light, which then hit the patient's cancer cells in the form of energy beams with high precision through a fixed or rotating therapy device.

There are only 10 hospitals around the world that can provide heavy ion therapy, and the cost of going abroad for such treatment reaches 100 to 200 million won. Japan, where most of patients visit for the treatment, introduced the world's first heavy ion therapy system in 1994 and has already been providing heavy ion therapy for 28 years.

Now it is possible to receive heavy ion therapy in Korea too.

The Yonsei University Health System announced on January 25th that it will start heavy ion therapy in the first half of the year for the first time in Korea. It is expected to be a new hope for patients with intractable cancer in Korea.

Heavy ion therapy shows a superior effect to the existing radiation therapy and proton therapy that are currently operated by hospitals in Korea. It is known that the biological efficacy of heavy ions is 2 to 3 times better than that of X-rays and protons.

This is because the mass of a heavy ion, i.e., carbon ion, is 12 times higher than that of a proton, and thus the impact strength on cancer cells is greater with the heavier ion. In addition, the impact on cancer cells can be increased due to the nature of heavy ions that emits maximum energy at the target.

Because X-rays affect all living tissues while they travel through the skin to cancer cells in the body, even if a strong impact to cancer cells is desired, the energy must be adjusted considering damages to normal cells.
On the other hand, heavy ions emit most of the energy on the target cancer tissue while radiating less on the body surface. Such a nature of heavy ions is called the Bragg peak.

Heavy ion therapy can be used for all solid cancers except blood cancer, and particularly it shows a strong effect on cancer cells in an oxygen-poor environment, which was difficult to treat in the past.

These hypoxic cancer cells have strong viability because they should survive even in oxygen-deprived conditions. They endure more than 100 times the radiation dose and are notorious for difficult treatment because it is difficult for anticancer drugs to penetrate through these environments.

The Yonsei University Health System presents three heavy ion therapy machines, one fixed and two rotating.

Because the rotating type irradiates heavy ions while rotating 360 degrees, it is possible to irradiate the patient's cancer cells intensively from any direction. This is how it could reduce the average number of treatments.

The average number of treatments is 12, which are only half of X-ray or proton therapy. Although the treatment time per patient is only about 2 minutes, the preparation requires some time, so the plan is to treat 50 patients in a day with three machines.

Patients feel little pain after treatment and thus they can go home right away.

Dr Yoon Dong Sup, the Head of the Yonsei University Health System, said, “Heavy ion therapy will more than double the survival rate in pancreatic cancer, lung cancer, and liver cancer, which are considered the three most intractable cancers because the 5-year survival rate is less than 30%. It is expected to be also widely used in the treatment of prostate cancer with its low side effects and excellent patient convenience compared to existing treatments as well as treatment of rare cancers such as bone and soft tissue sarcoma, chordoma, and malignant melanoma.”

[WIKI KOREA=Cho Pil Hyun, Staff Reporter]