Research News

Neurosurgeons at Cleveland Clinic’s Gamma Knife Center have identified features that help predict which patients with recurrent glioblastoma benefit from Gamma Knife radiosurgery. 

It’s important to know who might benefit from traveling to Ohio for this unique, noninvasive brain cancer treatment. Study lead author Lilyana Angelov, MD, says her team’s research offers clearer guidance for caregivers and patients as they make tough treatment decisions. The decision is time-sensitive, as glioblastoma often grows quickly. 

“At its core,” Dr. Angelov says, “this is about giving patients more time—time that is meaningful, and time we can help preserve with as little burden as possible.” 

Their findings, published in the Journal of Neuro‑Oncology, give clinicians a strategy for finding treatments that preserve their patients’ neurological function and quality of life. 

What is Gamma Knife radiosurgery? 

Gamma Knife radiosurgery (also called Stereotactic Radiosurgery/SRS) is a painless treatment where doctors use focused beams of radiation to destroy tumors.

Despite its name, it isn’t a traditional surgery. It doesn’t even use a real knife or a scalpel. Instead, physicians use advanced imaging to guide the radiation beam with accuracy down to a fraction of a millimeter. This accuracy makes Gamma Knife radiosurgery especially useful for treating small, well-defined brain lesions while preserving the healthy brain tissue.

Cleveland Clinic has the highest‑volume radiosurgery center in both Americas with over 1,000 cases performed each year. 

“Glioblastoma has a poor prognosis, and many systemic treatments cause serious side effects,” explains Dr. Angelov, who is Director of Cleveland Clinic’s Gamma Knife Center. “If a recurrence is small and in one area, and we can offer a high‑dose treatment that might extend survival without affecting quality of life, we owe it to patients to explore that option.” 

Defining when to use Gamma Knife for glioblastoma treatment 

Dr. Angelov and her team reviewed all recurrent glioblastoma cases treated at the Gamma Knife Center over the past 14 years. The research team examined features from old tumor biopsies, like how DNA changed in the tumor. They also examined clinical features like tumor size. 

“We want this therapy to be considered more widely, so we only analyzed data collected with diagnostic tools accessible to any modern hospital,” Dr. Angelov says. 

Their analysis revealed several characteristics strongly associated with improved survival after radiosurgery. Patients with at least two of these characteristics lived twice as long after radiosurgery, including: 

• Smaller tumor size
• Longer time between remission and recurrence
• Specific genetic features in the tumor 

The project also involved physician‑scientists who study glioblastoma biology, including Jennifer Yu, MD, PhD, and Andrew Dhawan, MD, DPhil. Dr. Angelov hopes her team's findings will inspire new bench‑to‑bedside research to improve radiosurgery outcomes for even more patients faced with glioblastoma. 

“Good clinical questions often push us back to the lab,” she says. “That’s how progress happens.”