Understanding to Innovate

Capital Expansion > Understanding to Innovate

Understanding to Innovate

Sungjune Kim, M.D., Ph.D., is focused on the clinical evidence for carbon ion therapy, aiming to drive innovation through a deeper understanding of the underlying biology.

By Dan Samorodnitsky, Ph.D. Photography by Paul Flessland

Share

Share this:

By the time most students are finishing medical school, they have a pretty good idea what specialty they’re most interested in.

It took Sungjune Kim, M.D., Ph.D., a bit longer.

Dr. Kim, then a medical student at Vanderbilt University, considered multiple options. A career as a surgical oncologist was appealing, but so too was a research career, and marrying the two seemed difficult.

Dr. Kim waffled over his choice. He worried that the decision would lock him into a single track for the rest of his life. He didn’t want to limit his research options or miss out on working directly with patients. And he definitely didn’t want to stray far from the basic sciences, the first of his many academic loves.

Radiation oncology was the answer. Since 2023, Dr. Kim has been the vice chair of research in Mayo Clinic’s Department of Radiation Oncology. It’s an exciting time for the field and for patients, where an innovative technology is improving the precision and speed of care. Carbon ion therapy — also known as carbon ion radiation therapy or CIRT — can kill cancer cells that may be resistant to proton beam therapy, allowing for precise treatment with minimal damage to the surrounding tissue.

Dr. Kim works closely with Brad Hoppe, M.D., M.P.H., medical director of the Department of Radiation Oncology; physicist Chris Beltran, Ph.D.; and radiation oncologist Michael Story, Ph.D. Together, the group seeks to expand the technique’s reach. There are still unknowns about the deeper technical details of how carbon ion therapy works, which must be better understood if the therapy is to be extended to more patients.

“Because of the expenses associated with its infrastructure, we need to provide a really strong rationale for carbon ion therapy to be built to serve the U.S.,” says Dr. Kim.

Mayo Clinic is exploring carbon ion therapy from two directions. Dr. Beltran studies the physics of carbon ion and how it stimulates the immune system in ways that other particle therapies don’t. Dr. Story is building their combined carbon therapy research arm, helping to combine research to keep Mayo’s physicians up to date with critical new knowledge. This knowledge is critical to furthering carbon ion’s clinical applications.

"We really need to understand the underlying biology of carbon ion therapy to innovate the field."

Dr. Kim’s focus is on the clinical evidence for carbon ion therapy.

“We really need to understand the underlying biology of carbon ion therapy to innovate the field,” Dr. Kim says. “Because if it's a black box, and it could be just statistical noise, we would never be able to tell. So that is what I'm trying to set out to do — to give a clear rationale for why some patients may benefit from the escalated therapy with carbon ions.”

Curious From the Start

Dr. Kim excelled at math as a child in South Korea and showed enough promise to earn admission to the ultra-competitive Seoul Science High School for Gifted Students. The school is known for its rigorous selection process and the achievements of its alumni. Of the 180 students in Dr. Kim’s class, about 140 have earned Ph.D.s.

Early in his schooling, Dr. Kim believed he’d be a theoretical physicist like Albert Einstein, but he grew to feel that it would be hard to contribute much more to the field.

So he decided to study chemistry at Seoul National University. It felt like a middle ground. He could go back into physics if he wanted, given the closeness of the fields, but it also left open the possibility of biology, which he viewed as more practical.

Dr. Kim’s interests changed again after he was inducted into the army in South Korea, where military service is compulsory.

Because of his strong English, he expected to serve as a liaison between the South Korean and U.S. armies. Instead, since Dr. Kim’s English was so proficient, the South Korean Army decided to put him in their own medical school to train medics.

That was his first exposure to medicine, and he wasn’t immediately sold. Initially he thought medicine was a purely clinical practice, and after his service he considered going back to a basic science research program.

“I was just flip-flopping,” Dr. Kim says. There were simply too many choices to make. So, he kept his options open while pursuing an M.D.-Ph.D. program, landing at Vanderbilt University in Nashville, Tennessee.  

Finding His Path

Dr. Kim started taking immunology classes at Vanderbilt. He was attracted to the “complex systems with complex problems that challenged your brain.”

He’d done his graduate school research on natural killer T cells, a critical cellular component of innate immune systems, a commonly mutated cell in a variety of cancers, and a common culprit in skin allergies.

As he neared graduation, he contemplated dermatology and rheumatology. Neither felt like the right fit. Instead, he gravitated to radiation oncology. Dr. Kim had the heavy physics background needed for the field, and it helped him stand out among his medical school colleagues.

Dr. Kim interviewed for residencies in 2009, before any immune checkpoint therapy like a PD-1 inhibitor had been available for patients.

“People gave me looks for being an immunologist going into radiation oncology,” he says. “Cancer immunotherapy was more of a discovery area, not in practice yet.”

During his residency, Dr. Kim was exposed for the first time to carbon ion radiation as a treatment modality. He loved the pure physics of carbon ion and was impressed with the benefits offered by the therapy.

“It has high LTE — linear energy transfer — which leads to higher relative biological effects, while retaining the treatment abilities of particle therapy,” Dr. Kim says.

Low-energy photon beams, if shot at a human body, will just bounce right off. High-energy photon beams — like X-rays — will penetrate deep into the body, but deposit radiation along their paths, which can damage healthy tissue. Carbon ion therapy has a unique physical property that precisely delivers a radiation dose within a millimeter-sized target into tumors, reducing the risk to the surrounding tissue.

While there are mysteries about carbon ion therapy, there are already some answers as to why it works. It stimulates the immune system, and it damages cancer cell DNA. The therapy hasn’t had a direct path to patient care, something Dr. Kim can relate to from his past.

In the 2000s when Dr. Kim was a student, research into new cancer immunotherapies was in its infancy, in preclinical studies in mice and cell lines.

"That is what I'm trying to set out to do — to give a clear rationale for why some patients may benefit from the escalated therapy with carbon ions."

“There was basically no human relevance at that point in time,” Dr. Kim says. But evidence began to pile up, and the field, along with Dr. Kim, took notice. “When it took off, it took off very, very quickly.” Dr. Kim and the entire Mayo Clinic radiation team — with unique expertise in the physics and immunology of the field — are expecting the same quick takeoff.