Soy isoflavones administered before and after radiation protected lungs against adverse effects, including skin injury, hair loss, increased breathing rates, inflammation, pneumonitis and fibrosis, according to study results published in the Journal of Thoracic Oncology.
In a preclinical lung tumor model, soy isoflavones exhibited the potential to enhance radiation damage in tumor nodules while simultaneously protecting noncancerous lung tissue from radiation injury.
To determine whether supplementation with soy isoflavones could improve high-dose radiotherapy for inoperable non–small cell lung cancer by alleviating radiation injury to lung tissue, researchers treated naive Balb/c mice with oral soy isoflavones for 3 days before and up to 4 months after radiation.
Radiation was administered to the left lung at 12 Gy. Mice were examined for toxicity and breathing rates at 2, 3 and 4 months after radiation. Lung tissues also were processed for histology for in situ evaluation of response.
According to study results, supplementation with soy isoflavones protected mice against radiation-induced skin injury and hair loss. Lung irradiation was found to cause an increase in breathing rate that was more pronounced by 4 months after radiation, due to the late effects of radiation-induced injury to normal lung tissue. However, this effect was mitigated by soy isoflavones.
Upon histological examination, irradiated lungs exhibited a chronic inflammatory infiltration involving alveoli and bronchioles and a progressive increase in fibrosis, which were alleviated by soy isoflavones.
“Our experimental studies in animal models suggest that the addition of soy to radiotherapy might improve the effect of radiotherapy on the tumor target and reduce the dose-limiting toxicity of radiotherapy to the normal lung,” the researchers wrote. “If this proves to be the case, this simple, nontoxic, natural compound would radically improve the effectiveness of this new radiation treatment for inoperable NSCLC.”
Disclosure: The researchers report no relevant financial disclosures.