Gut Microbiome Tied to Radiation Therapy Outcomes in HNC

M. Alexander Otto, PA, MMS

August 12, 2022

The studycovered in this summary was published on as a preprint and has not yet been peer reviewed.

Key Takeaway

Why This Matters

  • Although it is becoming clear that the gut microbiome can influence radiation therapy, immunotherapy, and chemotherapy outcomes, its influence in head and neck cancer has not been previously reported.

  • The findings begin to define the role of gut microbiota in HNC and, if confirmed, identify microbial populations suitable for probiotic preconditioning to optimize radiation outcomes.

Study Design

  • The team analyzed the microbial composition of stool samples from 20 patients with HNC before radiation therapy and correlated the results with oral mucositis severity and tumor recurrence.

Key Results

  • About half of patients developed grade 3-4 oral mucositis.

  • Six pro-inflammatory bacterial genera were enriched in patients with severe oral mucositis, with Eubacterium, Victivallis, and Ruminococcus most significantly increased.

  • Of 17 patients analyzed, tumors recurred in three (18%); these patients had cancers of the oropharynx, nasal cavity, or salivary glands.

  • Patients who did not have recurrence had a significantly higher abundance of Faecalibacterium, Prevotella, and Phascolarctobacterium, three genera that have previously been linked to better immunotherapy outcomes in patients with melanoma and non–small cell lung cancer.


  • This was a small study with substantial differences between patients, including differences in tumor sites and treatments.


  • The study was supported by the Royal Adelaide Hospital.

  • The investigators had no disclosures.

This is a summary of a preprint research study, "Baseline Gut Microbiota Composition Is Associated With Oral Mucositis and Tumor Recurrence in Patients With Head And Neck Cancer: A Pilot Study," led by Ghanyah Al-Qadami of the University of Adelaide, provided to you by Medscape. The study has not been peer reviewed. The full text can be found at

M. Alexander Otto is a physician assistant with a master's degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who has worked for several major news outlets before joining Medscape and also an MIT Knight Science Journalism fellow. Email: Email:

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