Periodontal bacteria linked to head and neck cancer

Dental Tribune International

Wed. 16 October 2024

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NEW YORK, US: Studies have repeatedly shown that oral bacteria can contribute to periodontal disease. Now, researchers have sought to examine whether there is a correlation between the oral bacterial and fungal microbiome and the risk of developing head and neck squamous cell carcinoma (HNSCC). In what is considered the largest and most detailed analysis of its kind to date, they found that oral bacteria could be a risk factor for HNSCC development given that some bacterial species in the mouths of the study participants were associated with a doubled likelihood of developing HNSCC.

The study, conducted by researchers at NYU Langone Health, analysed data from three ongoing investigations involving 159,840 healthy participants. The investigations aim to gain a deeper understanding of how factors such as diet, lifestyle and medical history contribute to cancer risk. Shortly after enrolment, participants provided saliva samples, and the researchers tracked the participants for approximately ten to 15 years to examine their genetic make-up of oral microbes and monitor the development of cancer. A total of 236 patients were diagnosed with HNSCC, and the researchers compared the DNA of their oral microbes with that of 458 frequency-matched cancer-free study participants.

According to the findings, 13 oral bacterial species were differentially associated with the onset of HNSCC. Among these were Prevotella salivae, Streptococcus sanguinis and Leptotrichia species—a novel finding—along with several species of the Betaproteobacteria and Gammaproteobacteria classes. Overall, these bacterial species were associated with a 30% higher likelihood of developing HNSCC. When combined with five other species commonly found in periodontal disease, the overall risk increased to 50%.

“Our findings offer new insight into the relationship between the oral microbiome and head and neck cancers,” lead author Dr Soyoung Kwak, a postdoctoral fellow in the Department of Population Health at the NYU Grossman School of Medicine, said in a press release. “These bacteria may serve as biomarkers for experts to flag those at high risk,” she added.

Co-author Dr Richard B. Hayes, a professor in the Department of Population Health, commented: “Our results offer yet another reason to keep up good oral hygiene habits.” He added: “Brushing your teeth and flossing may not only help prevent periodontal disease but also may protect against head and neck cancer.”

Having identified the key bacteria that potentially contribute to HNSCC, the researchers plan to investigate the mechanisms by which these bacteria exert their effects and determine the most effective ways to intervene.

The study, titled “Oral microbiome and subsequent risk of head and neck squamous cell cancer”, was published online on 26 September 2024 in JAMA Oncology, ahead of inclusion in an issue.