S.aureus Colonization linked with pathogenesis of Acute radiation dermatitis

New research revealed that in patients with head, neck, and breast cancer staphylococcus aureus nasal colonization was associated with the development of grade 2 or higher acute radiation dermatitis and may also be associated with the pathogenesis of radiation dermatitis. The study results were published in the journal JAMA Oncology.  

Acute radiation dermatitis generally begins weeks after radiation therapy and the symptoms include severe skin erythema, dryness, moist or dry desquamation, and/or ulceration, that may interrupt radiotherapy. After radiation therapy, pro-inflammatory cutaneous microorganisms may contribute to cutaneous inflammation. The pathogenesis of acute radiation dermatitis (ARD) remains unknown. Hence researchers conducted a prospective cohort study to evaluate whether nasal colonization with Staphylococcus aureus (SA) before radiation therapy is associated with ARD severity in patients with breast or head and neck cancer. 

The study was conducted from July 2017 to May 2018 at an urban academic cancer center with observers blinded to colonization status. Patients aged 18 years or older with breast or head and neck cancer and plans for fractionated radiation therapy (≥15 fractions) with curative intent were enrolled via convenience sampling. The primary outcome was the ARD grade using the Common Terminology Criteria for Adverse Event Reporting, version 4.03.

Key findings: 

• Among 76 patients analyzed, the mean (SD) age was 58.5 (12.6) years, and 56 (73.7%) were female.
• Among 76 patients who developed ARD, there were 47 (61.8%) with grade 1, 22 (28.9%) with grade 2 and 7 (9.2%) with grade 3.
• When compared to those who developed grade 1 ARD, the prevalence of baseline nasal SA colonization was higher among patients who developed grade 2 or higher ARD. 

Thus, in patients with breast or head and neck cancer, baseline nasal colonization of Staph aureus was linked to the development of grade 2 or higher ARD. 

Further reading: 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 04, 2023. doi:10.1001/jamaoncol.2023.0454