A new clinical trial will incorporate imaging of lung function into radiation therapy for patients with lung cancer. The trial, registered at ClinicalTrials.gov as NCT02528942, aims to apply advanced image analysis techniques to 4-dimensional computed tomography (4D CT) scans. These scans already are a standard step in targeting lung cancer radiotherapy, and the trial seeks to map areas of lung function without additional testing.
“We used to treat the lungs as a homogenous organ, as if all areas were equally important. Now we know that’s not true; there’s regionally variant function. The idea of this clinical trial is to spare functional portions of the lung during radiation by using this new imaging modality to display lung function,” said principal investigator Yevgeniy Vinogradskiy, PhD. He is at the University of Colorado (CU) Cancer Center and an assistant professor in the Department of Radiation Oncology at the CU School of Medicine.
Lung tumors move along with a patient’s breath, so single images of a tumor’s position are not precise as breathing occurs. Past techniques used crude approximations during radiation therapy to consider the patient’s breathing.
In the early 2000s, 4D CT was developed. The method uses a series of images shot over time to capture the position of the lung and the tumor during all phases of the breathing cycle (time being the fourth dimension in 4D CT). 4D CT is standard-of-care for most lung cancer patients because it helps radiation oncologists develop a personalized plan that accounts for breathing motion during therapy.
The radiation therapy is aimed away from the highest functioning portions of lungs while still delivering the intended radiation dose to the tumor. If lung function is considered when drawing up plans for radiation treatment, the hope is that lung function after radiation therapy will be spared. This will result in improved quality of life for patients.
“One of the neat things about it is there’s no extra procedure required for patients. All of the lung function information used to optimize the radiation treatment plan comes from imaging that is already acquired as part of standard of care,” said Vinogradskiy.
The current clinical trial will enroll 70 patients, and it plans to finish in 3 years.
“We’ve demonstrated that the concept works in retrospective studies but this is really the first step in integrating the novel imaging and treatment prospectively in patients. From here, we hope to show compelling results that could lead to a national clinical trial. It’s still very early, but this system has the potential to become the standard way that radiation therapy treatments are done in lung cancer patients,” Vinogradskiy said.
The trial is funded by the National Institutes of Health.