Author: Alex Biese
Among patients with squamous cell head and neck carcinoma, oral microbiome is associated with severity of oral mucositis (OM), an after-effect of radiotherapy and chemotherapy which effects nearly all patients with head and neck cancer (HNC), according to recent study findings from a team at The University of Texas MD Anderson Cancer Center.
“Our study suggests that the oral microbiome plays an important role in the longitudinal patterns of OM and the potential interaction between the oral microenvironment and the development of OM in patients with HNC,” the researchers wrote in a study published in the journal Cancer.
Drawing on data from 142 adult patients — 91% male, with an average age of 57.6 years and a mean BMI of 29.1, 80% of whom had oropharyngeal carcinoma and 75% of whom received chemoradiation — newly diagnosed with locoregional squamous cell carcinoma of the head and neck who were treated at MD Anderson Cancer Center between March 2016 and September 2020, researchers collected samples from patients at the baseline prior to treatment, weekly during treatment, during the clinic visit at the conclusion of treatment and after the termination of treatment.
The American Academy of Oral Medicine cites high-dose chemotherapy and localized high-dose radiation therapy to the head and neck region as the main risk factors for developing painful mouth sores also referred to as oral mucositis.
“These treatments effectively target the rapidly dividing cancer cells, but also inadvertently affect normal healthy cells that rapidly turnover, such as the oral mucosa lining of the inside of the mouth,” as the American Academy of Oral Medicine explained on its website. “A complicated series of biological events are triggered that ultimately compromise the integrity of the oral mucosa. Minor trauma to the mouth from speaking, chewing, and swallowing, is sufficient to breakdown the mucosa, resulting in the formation of painful ulcerations.”
The team from MD Anderson Cancer Center, it its recent study, noted findings published in the Journal of Experimental and Clinical Cancer Research which found that approximately 90% of patients with head and neck cancer treated with chemotherapy and radiotherapy experience oral mucositis.
Researchers from MD Anderson Cancer Center bundled participants with similar patterns of OM severity into four latent groups (LGs): early onset of high OM scores (LG1), relatively low OM scores until weeks eight and 11 (LG2 and LG3, respectively) and generally flat OM scores (LG4), as explained in the study, which noted that LGs did not vary by treatment, clinical or demographic variables.
“At baseline before cancer treatment, we found similar microbial diversity within each subject,” the study authors wrote. “We also found a fairly stable microbial diversity within each subject over time. Importantly, when we assessed which specific microbial features were correlated with the longitudinal patterns of OM severity, we found a number of significant microbial features correlated with the mucositis scores across the four LGs, including the phylum Bacteroidota, phylum Proteobacteria, class Bacteroidia, class Gammaproteobacteria, order Enterobacterales, order Bacteroidales, family Aerococcaceae, family Prevotellaceae, genus Abiotrophia, and genus Prevotella_7, which suggests these microorganisms may potentially affect OM progression.”
In turn, researchers posited that the identified microbial features may serve as potential candidates for oral mucositis prevention and treatment.
“We noted that the direction of the association of the microbial features varied with OM severity and persistence,” the authors wrote. “These findings suggest the potential to personalize treatment plans. The administration of antibiotics to reduce the presence of unfavorable microbial features positively correlated with OM severity could be a potential intervention strategy. Conversely, the use of probiotics to increase the abundance of protective bacteria that are negatively correlated with OM severity would offer an alternative therapeutic approach.”