Fox Chase Cancer Center Researchers Show Adaptive Radiation Therapy Delivers Treatment More Effectively in Study Presented at American Society for Radiation Oncology Meeting

Robert Freeman, MD, the study's lead author and a second-year resident in the Department of Radiation Oncology.

PHILADELPHIA (September 30, 2024) - Online adaptive radiation therapy (ART) delivered radiation more effectively than conventional radiation therapy in nearly half of patients, while also helping to decrease radiation dose to the esophagus in a majority of patients with thoracic spine tumors. That's according to the results of a study presented today by Fox Chase Cancer Center researchers at the American Society for Radiation Oncology (ASTRO) Annual Meeting in Washington, D.C.

The researchers performed a retrospective review of ART delivered to patients with spinal metastases at Fox Chase's Department of Radiation Oncology, said Robert Freeman, MD, the study's lead author and a second-year resident in the department. "In doing this, we believed that we would find the adaptive technology would reduce the dose to those surrounding organs at risk," added Freeman, who conducted the study with several other department colleagues.

ART is a treatment technique in which imaging and replanning of therapy can be done immediately before delivery of the treatment. This process is done in combination with what is called a scheduled plan.

"Typically, patients come in for something called a simulation before they receive radiation. During that appointment, the patient will get some imaging, and we use that imaging to identify the target, which is the tumor. We also identify the surrounding organs at risk so that we know that we are targeting what we need to target and sparing the tissue that we need to spare," said Freeman.

With ART, two different treatment plans are created - the scheduled plan created from the simulation and onboard imaging, and the adaptive plan, which is updated based on the replanning done with same-day imaging. The two plans are compared, and the one deemed most effective is selected based on tumor coverage - how much radiation is delivered to the tumor - and how well surrounding tissue is spared.

"We hypothesized that we would be decreasing the dose to organs at risk with the adaptive technology, but what we didn't expect was that we were also getting better coverage of the thoracic metastases. Almost half the patients getting treatment with the adaptive technology had better tumor coverage, which was impressive," said Freeman.

He added that next steps include evaluating whether this improved tumor coverage translates into better outcomes for patients both in terms of tumor control and side effects.

The results of the study, "Adaptive Radiation Therapy (ART) of Spinal Metastases: Motion Between a Rock and a Hard Place," were presented during a poster session at the ASTRO meeting.