June 18, 2020 -- Low-dose chest radiation, usually given in a single treatment, may reduce inflammation in the lungs of severely ill COVID-19 patients enough to wean them off a ventilator or avoid it altogether. Several clinical trials of the treatment are underway or launching in the U.S. and elsewhere.
The radiation works to offset an immune system overreaction known as a “cytokine storm” that happens in some patients with COVID, says Arnab Chakravarti, MD, a professor and chair of radiation oncology at Ohio State University. In a cytokine storm, the body starts to attack its own cells and tissues rather than just fighting off the virus.
Chakravarti is leading two clinical trials -- one will test the treatment in patients already on a ventilator, and the other will give the treatment to patients on oxygen to try to prevent the need for a ventilator.
"Radiation at these low doses usually doesn't have a direct antiviral effect," he says. "But it does reduce inflammation. And when the inflammation is reduced, the acute [ill] effects of the byproducts of pneumonia also subside," says Chakravarti, who is also the Klotz Family chair of cancer research at OSU's Comprehensive Cancer Center -- Arthur G. James Cancer Hospital.
Researchers at Emory University's Winship Cancer Institute are also testing the therapy. In their early analysis of five COVID-19 patients treated with radiation therapy, three were taken off supplemental oxygen within 24 hours of the treatment, and a fourth after 96 hours. The patients were 64 to 94 years old. The results are reported in a preprint, which is not yet peer-reviewed.
Researchers in Italy, India, Iran, and Spain are also studying the treatment.
The treatment was used after the 1918 influenza pandemic to treat flu-related viral pneumonia, Chakravarti says, and has also been used for arthritis.
The dose for COVID-19 patients ''would be a little higher than the dose of a typical CT scan, but magnitudes lower than when it is used to treat lung cancer," he says. "At these very low doses, the treatment should be safe for most patients, but it really should be done in a clinical trial."
How did the treatment come into play again for COVID-19? "Many of the thought leaders in radiation oncology thought if these ultra-low doses work for influenza-mediated viral pneumonia, why wouldn't it work for COVID-19-mediated pneumonia as well," Chakravarti says.
The study to test the therapy in ventilated patients, called VENTED, will only be done at Ohio State, with a goal of enrolling 24 patients. The study testing the therapy to prevent the need for a ventilator, called PREVENT, will include up to 21 hospitals across the country, Chakravarti says. Varian Medical Systems, which makes radiation oncology treatments, provided funding for the PREVENT study.
William Small Jr., MD, chair of the Radiation Oncology Commission for the American College of Radiology, called radiation therapy “another tool to try.”
He says he hopes to join the multi-center study led by Chakravarti.
In his prior research, Small has found that radiation therapy can prevent kidney transplant rejection by effecting the immune system.
In late April, researchers from Iran reviewed radiation treatment for COVID-19 in a radiation oncology journal, cautioning that "there is limited knowledge about the interaction of low dose radiation therapy and viruses." They warned that some research has reported the spread of some viruses after radiation treatment, but the studies they cite did not involve the coronavirus that causes COVID-19.