Yonsei Cancer Hospital expands heavy-ion therapy to head and neck cancers, sarcomas and recurrent rectal cancer

Yonsei Cancer Hospital announced Wednesday that it is expanding its heavy-ion therapy program to cover head and neck cancers, sarcomas and recurrent rectal cancer.

The hospital became the first in South Korea to offer heavy-ion therapy for prostate cancer in 2023, and has since extended the treatment to pancreatic, liver and lung cancers. The latest expansion adds three more cancer types to the program.

Alongside the expanded indications, the hospital's second rotating heavy-ion therapy unit has entered full operation. The facility is now the world's first medical institution to run all three of its units simultaneously — one fixed and two rotating.

Heavy-ion therapy exploits the "Bragg peak" effect, which concentrates energy in tumor tissue while minimizing damage to surrounding healthy tissue. The rotating units revolve 360 degrees around a patient, delivering heavy-ion beams from multiple angles and allowing clinicians to tailor the direction of irradiation to the tumor's location, shape and proximity to critical organs.

Head and neck cancer, one of the newly added indications, refers broadly to malignancies arising in the region between the base of the skull and the collarbone, including the oral cavity, pharynx, larynx, nasal cavity, paranasal sinuses and salivary glands. The cancers eligible for heavy-ion therapy are non-squamous cell carcinomas — such as adenoid cystic carcinoma and mucosal malignant melanoma — that are resistant to conventional radiation and arise in surgically difficult sites including the nasal and paranasal sinuses, skull base and salivary glands.

The head and neck region is densely packed with structures essential for breathing, speaking and swallowing, as well as the brain, spinal cord, optic nerves, and major blood vessels and nerves. Preserving respiratory, vocal, swallowing and cosmetic function after treatment is therefore as important as eliminating the tumor. Heavy-ion therapy can control the tumor while protecting normal tissues such as the brain, optic nerves, spinal cord and salivary glands, the hospital said.

Sarcomas also present significant challenges for surgery and conventional radiation. These malignant tumors arise in connective and supportive tissues — bone, muscle, fat, blood vessels and nerves — and are difficult to remove completely when they develop in surgically inaccessible sites such as the spine, pelvis, sacrum or skull base, or when they invade major nerves and blood vessels.

When complete resection is not possible, or when cancer persists or recurs after surgery, radiation therapy is used — but sarcomas are highly resistant to conventional radiation and require high doses. The proximity of critical structures such as the spinal cord, intestines and nerves makes it difficult to deliver sufficient doses safely.

Recurrent rectal cancer is similarly considered difficult to treat. It involves tumor regrowth within the pelvis after curative resection, and when the recurrent tumor invades the sacrum, pelvic wall, bladder, ureter or nerves, surgical resection carries a heavy burden of complications. Patients who have already received pelvic radiation face the additional challenge of cumulative dose limits.

The cancer types now added to the heavy-ion therapy program are frequently resistant to conventional radiation or unsuitable for surgery. Using the rotating units, clinicians can precisely irradiate tumors from multiple angles based on their location and shape.

A Japanese multicenter study, J-CROS, found that heavy-ion therapy for patients with surgically difficult recurrent rectal cancer achieved a three-year local control rate of 93 percent and a five-year rate of 88 percent. For some inoperable head and neck cancers, five-year local control rates of 68 to 95 percent have been reported depending on the cancer type.

With the second rotating unit now fully operational, Yonsei Cancer Hospital said it has built the capacity to treat about 40 patients a day and 10,800 patients a year.

"For refractory tumors in areas densely packed with critical organs — where surgery is difficult or conventional treatment has failed — the key is to enhance therapeutic effect while reducing damage to healthy tissue," said Keum Woong-seop, director of the hospital's Heavy Ion Therapy Center. "By bringing the second rotating unit into full operation, we are expanding personalized treatment that simultaneously protects surrounding normal organs and effectively controls radiation-resistant cancer cells."