Researchers have found that acute radiation dermatitis may involve the skin bacterium Staphylococcus aureus and that a simple, low-cost treatment may prevent severe cases in patients undergoing radiation therapy, according to two novel studies published by Kost et al—one a randomized clinical trial and the other a prospective cohort study—in JAMA Oncology.
In the first study, the researchers collected bacterial cultures from 76 patients with cancer before and after treatment with radiation therapy. The cultures were sampled from three different body sites: inside the nose, from skin in the area exposed to radiation, and from skin on the side of the body not exposed to radiation. Prior to treatment, about 20% of the patients tested positive for S aureus bacteria but did not have an active infection. Following treatment, the researchers found that 48% of the patients who developed severe acute radiation dermatitis tested positive for the presence of S aureus bacteria compared with only 17% of those who developed the mildest form of the condition. Many patients with the bacteria on their skin also tested positive for nasal S aureus bacteria—suggesting that bacteria from the nose might be infecting the skin.
In the second study, researchers randomly assigned 77 patients—75 of whom were undergoing radiation therapy for breast cancer—to receive the experimental antibacterial regimen of the body cleanser chlorhexidine in combination with mupirocin 2% nasal ointment administered twice daily for 5 days, every other week throughout their radiation therapy, or standard-of-care hygiene and moisturizing treatments. Although over 50% of the patients who received the antibacterial regimen developed mild-to-moderate acute radiation dermatitis, none of them developed moist desquamation or experienced adverse effects from the treatment. In contrast, severe acute radiation dermatitis affected 23% of the patients receiving the standard-of-care treatment.