A peer-reviewed journal that offers evidence-based clinical information and continuing education for dentists.

Oral Bacteria, Systemic Diseases and Cancer

Wouldn’t it be wonderful if dental professionals could increase the systemic health of our patients by reducing inflammation in the form of periodontal disease.


Some years ago, a friend and longtime patient passed away from oral cancer. A dental hygienist in our practice first sighted the lesion during a routine periodontal maintenance visit. It was a small, white, slightly raised area on the posterior pharyngeal wall on the patient’s right side. A biopsy was performed and the diagnosis confirmed squamous cell carcinoma. The edges of the lesion were not clean. In lieu of further resection and radiation, the patient opted for nontraditional therapy. This quest took him to numerous professionals and nonprofessionals in attempts to slow the lesion’s progress. The last time I saw him in the office, he had an external growth associated with the lesion that measured approximately 5 cm across. He died shortly thereafter.

This was all brought back to me recently when I came across an article on the relationship of oral bacteria to this type of lesion.1 The authors detailed previously known risk factors for two subcategories of esophageal cancers, esophageal adenocarcinoma (EAC), and esophageal squamous cell carcinoma (ESCC). Known risk factors for EAC include esophageal reflux disease, obesity, low fruit and vegetable intake, and smoking. Risk factors for ESCC include drinking alcohol, low fruit and vegetable intake, and smoking. But the authors concluded the etiology of these diseases could not be completely explained by these risk factors alone.


Using a prediagnostic mouthrinse to gather samples for gene sequencing, the researchers found that the periodontal pathogen Tannerella forsythia was associated with a higher risk of EAC, while lower risk was associated with depletion of the genus Neisseria and Streptococcus pneumoniae. The ubiquitous periodontal pathogen Porphyromonas gingivalis was strongly associated with a higher risk of ESCC. P. gingivalis has been long associated with periodontal disease and, as was previously described in this column, has been found to be associated with inflammation in other parts of the body.

So what are the takeaways here? While recurrence does occur with EAC and ESCC, early detection, surgical removal and radiation have proven effective in a large percentage of these cases. Nontraditional therapies have not. This also highlights the need for routine cancer examinations for dental patients.

More and more frequently, we are finding that oral bacteria are associated with systemic diseases. While a great deal of further work is needed on these associations, it is becoming clear these organisms are probably not innocent bystanders. Wouldn’t it be wonderful if dental professionals could increase the systemic health of our patients by reducing inflammation in the form of periodontal disease and, at the same time, reduce or eliminate the bacteria that appear to have such negative systemic consequences. This is a worthy goal, for certain.

Thomas G. Wilson Jr., DDS
Editor in Chief


  1. Peters BA, Wu J, Pei Z, et al. Oral microbiome composition reflects prospective risk for esophageal cancers. Cancer Res. 2017;77:6777–6787.

From Decisions in Dentistry. February 2018;4(2):6.

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