Prophylaxis With Antibacterial Topical Treatment May Reduce Acute Radiation Dermatitis Severity

Beth N. McLellan, MD

New research suggest that acute radiation dermatitis (ARD) may involve a common skin bacterium, rather than a burn from radiation, and that a topical antibacterial regimen may help prevent severe cases among patients with breast and head and neck cancer, according to 2 studies published in JAMA Oncology.^1,2

“Until now, ARD was assumed to result simply from the skin being burned by the radiation, which meant that not much could be done to prevent it,” Beth N. McLellan, MD, director of supportive oncodermatology at Montefiore Einstein Cancer Center, and chief of the Division of Dermatology at Montefiore Health System and Albert Einstein College of Medicine, said in a news release. “The readily available treatment we’ve developed and clinically tested could potentially save hundreds of thousands of people each year in the [United States] from severe ARD and its excruciating [adverse] effects [AEs].”³

Findings from a phase 2/3 trial (NCT03883828) showed that, although more than half of patients receiving the antibacterial regimen experienced (n =39) mild-to-moderate ARD, none developed moist desquamation—which is the most severe type of ARD and causes the skin to break down and develop sores. In the control arm (n = 38), 23.7% of patients experienced severe ARD.³

The antibacterial regimen consisted of the body cleaner chlorhexidine gluconate, 4%, along with mupirocin 2% nasal ointment, twice daily, for 5 days prior to radiation treatment and continued, every other week, throughout their radiation treatment.

The study enrolled 77 patients receiving radiation therapy, 75 of whom had breast cancer, and 2 of whom had head and neck cancer. Participants were randomly assigned to receive either experimental antibacterial regimen or standard of care treatment with normal hygiene and moisturizing treatment. The mean age was 59.9 years, 75 were women, and most patients were Black (33.7%) or Hispanic (32.5%).¹

In terms of radiation therapy, the median dose was 52.4 Gy (IQR, 42.4-52.4). This was delivered at a median of 20 fractions (IQR, 16-20).

Ultimately, the mean ARD grade was significantly lower among patients who were in the antibacterial regimen cohort, than in those receiving standard of care (P = .02). Among patients who received the regimen, 69.2% reported treatment adherence, and 1 patient (2.5%) reported a treatment-related AE (itch).

“Our regimen is simple, inexpensive, and easy so we believe it should be used for everyone undergoing radiation therapy, with no need to first test individuals for Staphylococcus aureus [SA],” McLellan said. “I expect this will completely change protocols for [individuals] undergoing radiation therapy for breast cancer.”

Reconsidering The Origin of Radiation Dermatitis

SA bacteria was associated with severe ARD in a study simultaneously published simultaneously in JAMA oncology.2 In a population of 76 patients undergoing radiation therapy for cancer, 48.3% of those who developed severe ARD (n = 29) also tested positive for SA after treatment began. In comparison, only 13% of those who experienced mild ARD tested positive for SA.

SA colonization is typically found on the skin, particularly in the nose and in the armpits. For most individuals, it is harmless but can cause infections if the skin is broken, which can occur during radiation because the skin structure can weaken at the treatment site.

Because SA is associated with skin disorders that lead to skin breakdowns, such as eczema, investigators hypothesized that it may also be implicit in ARD development. To test this theory, they analyzed 76 patients who were being treated at the Montefiore Einstein Cancer Center and collected bacterial culture from these patients before and after radiation treatment. The study period spanned from July 2017 to May 2018 and included patients who were at least 18 years of age and had either breast or head and neck cancer. All patients were receiving fractionated radiation therapy (at least 15 fractions) with curative intent.²

Cultures were collected from inside the nose, from skin in the radiated area, and from skin on the side of the body not exposed to radiation. The ARD was graded in accordance with Common Terminology Criteria for Adverse Event Reporting, version 4.03.

All 76 patients developed ARD, 47 patients developed grade 1 (61.8%), 22 developed grade 2 (28.9%), and 7 developed grade 3 (9.2%). Baseline nasal SA colonization was associated with grade 2 or higher ARD vs grade 1 ARD (P = .02).²

“This study clearly showed that SA plays a major role in ARD,” McLellan noted. “The good news is we have a lot of tools to fight this bacteria.”

References

1. Kost Y, Deutsch A, Mieczkowska K, et al. Bacterial decolonization for prevention of radiation dermatitis: a randomized clinical trial. JAMA Oncol. Published online May 4, 2023. doi:10.1001/jamaoncol.2023.0444
2. Kost Y, Rzepecki AK, Deutsch A, et al. Association of Staphylococcus aureus colonization with severity of acute radiation dermatitis in patients with breast or head and neck cancer. JAMA Oncol. Published online May 4, 2023. doi:10.1001/jamaoncol.2023.0454
3. A simple antibacterial treatment solves a severe skin problem caused by radiation therapy. News release. Montefiore Einstein Cancer Center. May 4, 2023. Accessed May 15, 2023. https://www.prnewswire.com/news-releases/a-simple-antibacterial-treatment-solves-a-severe-skin-problem-caused-by-radiation-therapy-301816414.html