Supplementary Material for: Changes in the skin microbiome of a patient with head and neck cancer with severe radiodermatitis: A case report

Introduction: Identifying the skin microbiome associated with severe radiodermatitis could lead to the development of preventive care strategies and early healing interventions, which are currently lacking. In this study, we investigated changes in the skin microbiome of a patient with head and neck cancer who developed severe radiodermatitis from the initiation of radiation therapy to the resolution of dermatitis.
Case Presentation: An 82-year-old male underwent chemoradiotherapy with cisplatin (69.96 Gy/33 fractions) for recurrent laryngeal cancer after a total laryngectomy. At baseline, Cutibacterium accounted for 64.3% of the skin microbiome and Staphylococcus for 23.2%. During the occurrence of moist desquamation associated with severe radiodermatitis, Cutibacterium decreased sharply to 0.2%, whereas Staphylococcus increased to 91.0%. Species-level analysis revealed that Staphylococcus aureus was dominant at 50.6%, whereas Staphylococcus hominis and Staphylococcus epidermidis were identified at 0.4% and 1.7%, respectively.
Conclusion: These findings demonstrated that changes in the skin microbiome occur during the progression of severe radiodermatitis. The reduction in Cutibacterium and overgrowth of Staphylococcus, particularly Staphylococcus aureus, suggest their involvement in the development of severe radiodermatitis in patients with head and neck cancer.