Focus on the oral-systemic link between CRC and periodontal disease
Jannette Whisenhunt, RDH, BS, MEd, PhD
As we go further into our study of the oral-systemic link this month, we will look into something that has impacted my family personally. My mother has been diagnosed with colorectal cancer, and my family has spent several months helping her through biopsies, radiation, chemotherapy, surgeries, and rehabilitation. We have been very thankful that my mom has done well, but this experience is something I would not wish on anyone. It also made me think about this disease in another way. Is there a correlation between periodontal disease and a risk for colorectal cancer? Some studies seem to point in that direction. I think this is a very interesting connection, and I never would have thought that this disease would make my “list.”
A study by Momen-Heravi et al. suggested that “periodontal diseases including tooth loss might increase systemic inflammation, lead to immune dysregulation, and alter gut microbiota, thereby possibly influencing colorectal carcinogenesis.” One of their findings indicated that “women with fewer teeth, possibly moderate or severe periodontal disease, might be at a modest increased risk of developing colorectal cancer (CRC), suggesting a potential role of oral health in colorectal carcinogenesis.”1
We already know through many research studies that oral cancer is associated with “poor oral health, smoking, increased alcohol consumption,”2 so it would be probable that the bacteria from periodontal disease could be involved in other cancers. The concept of a link between colon cancer and periodontal disease began with research from two independent studies3,4 in 2011 that discovered one specific bacteria, Fusobacteria, seemed to follow tumors and was found in human colon cancers.5 Even today it is not known if Fusobacterium nucleatum, a common periodontal pathogen, is the cause of colon tumors, but a new study hints that it may be “an integral part of the cancer.”5 Whether the bacterium actually plays a role in causing or spurring the growth of cancer is not known, but according to Stanford microbiologist and infectious disease specialist David A. Relman, MD, “It is not unreasonable to say Fusobacterium is promoting or contributing to colon cancer.”5
“Fusobacterium nucleatum, a gram-negative anaerobe, is such an emerging pathogen that is quickly attracting attention of the medical and research communities. F. nucleatum is ubiquitous in the oral cavity, and absent or infrequently detected elsewhere in the body under normal conditions. Under disease conditions, however, F. nucleatum is one of the most prevalent species found in extraoral sites.”6 “F. nucleatum is one of the most abundant species in the oral cavity, in both diseased and healthy individuals. It is implicated in various forms of periodontal diseases, including the mild reversible form of gingivitis and the advanced irreversible forms of periodontitis, including chronic periodontitis, localized aggressive periodontitis, and generalized aggressive periodontitis ... The prevalence of F. nucleatum increases with the severity of disease, progression of inflammation, and pocket depth.”6
These studies seem to question whether this bacterium is a cause of other tumor infections, or if it is just a coincidence that it is found in these colorectal cancers. Several studies seem to indicate that it is a driver of tumorigenesis. “F. nucleatum has been detected in colonic biopsies of patients with IBD” (inflammatory bowel disease).6 With IBD being recognized as a risk factor for colon cancer, it makes sense that this bacterium can be found in both diseases.6
The concept of a link between colon cancer and periodontal disease began with research from two independent studies in 2011 that discovered one specific bacteria.
A study published in the journal Science in November 2017 “confirmed the presence of Fusobacterium in up to half of all colon tumors.”7 This study also looked at treating the bacterium with the antibiotic metronidazole. When mice that were infected with colon cancer tumors were treated with this antibiotic, it did slow the growth of the tumors a great deal. Since everyone has different gut microbiota, it is not suggested to treat IBD or colon cancer with metronidazole. It would also kill off the good bacteria in the gut, and we would not want to foster a dependence on antibiotics. But it is interesting to see possibilities into what the future could hold that someday we may be able to get rid of the bacteria in a way that would decrease the pathogenicity of CRC and decrease the severity of periodontal disease as well.
“Since F. nucleatum is prevalent in periodontal disease, the link between periodontal health and these human diseases needs to be explored.”6 Colorectal cancer is not the only cancer being studied for this bacterium. “Periodontal disease is a risk factor for non-Hodgkin lymphoma (NHL). Whether periodontal disease is a direct or indirect cause of NHL, or a marker of underlying systemic inflammation and/or immune dysregulation, warrants further investigation.”8
With more research being conducted, perhaps someday we will understand the implications of the bacteria involved with periodontal disease in a more detailed way than we do now. We have been exploring other studies that have indicated there are other periodontal bacteria such as Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Helicobacter pylori that have been linked to other types of cancers. It is exciting to see how we can impact our patients’ overall health and wellness. It gives us a new understanding of how important our home-care instructions can be for patients. Who would have thought that the education and training we offer our patients could possibly help keep them from getting cancer?
Jannette Whisenhunt,RDH, BS, MEd, PhD, is the Department Chair of Dental Education at Forsyth Technical Community College in Winston-Salem, N.C. Dr. Whisenhunt has taught since 1987 in the dental hygiene and dental assisting curricula. She has a love for students and served as the state student advisor for nine years and has won the student Advisor of the Year award from ADHA in the past. Her teaching interests are in oral cancer, ethics, infection control, emergencies and orofacial anatomy. Dr. Whisenhunt also has a small continuing education business where she provides CE courses for dental practices and local associations. She can be reached at [email protected].
1. Momen-Heravi F, Babic A, Tworoger SS, et al. Periodontal disease, tooth loss and colorectal cancer risk: Results from the Nurses’ Health Study. Int J Cancer. 2017;140(3):646-652. doi: 10.1002/ijc. 30486.
2. Seymour RA. Is oral health a risk for malignant disease? Dent Update. 2010;37(5)279-280, 282-283.
3. Castellarin M, Warren RL, Freeman JD, et al. Fusobacterium nucleatum infection is prevalent in human colorectal carcinoma. Genome Res. 2012;22(2):299-306. doi: 10.1101/gr.126516.111.
4. Kostic AD, Gevers D, Pedamallu CS, et al. Genomic analysis identifies association of Fusobacterium with colorectal carcinoma. Genome Res. 2012;22(2):292-298. doi: 1101/gr.126573.111.
5. Kolata G. Why is this bacterium hiding in human tumors? The New York Times website. https://www.nytimes.com/2017/11/23/health/bacteria-colon-cancer.html. Published November 23, 2017.
6. Yiping WH. Fusobacterium nucleatum: a commensal-turned pathogen. Curr Opin Microbiol. 2015;0:141-147. doi 10.1016/j.mib.2014.11.013.
7. Galeon D. A mysterious bacterium may be a critical part of cancer. Futurism website. https://futurism.com/mysterious-bacterium-critial-part-cancer/. Published November 27, 2017.
8. Bertrand KA, Shingala J, Evens A, et al. Periodontal disease and risk of non-Hodgkin lymphoma in the health professionals follow-up study. Int J Cancer. 2017;140 (5):1020-1026. doi: 10.1002/ijc.30518.