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Periodontal disease can be a potential risk indicator for colorectal cancer
Periodontal disease (PD) is a set of inflammatory conditions that affect the gums and bone that surround and support the teeth. PD is believed to increase systemic inflammation, trigger immune dysfunction, alter the body’s microbiome, and increase the chances of developing certain cancers, including colorectal cancer (CRC) .
A 2016 study analysed data from the Nurses’ Health Study and aimed to evaluate the relationship between PD and CRC incidence. The Nurses’ Health Study is among the largest research studies ever conducted to investigate the risk factors for major chronic diseases. The investigators found that the risk of developing CRC increased by as much as 48% in women with periodontal disease, and cancer risk increased with the severity of tooth loss5.
A 2021 Chinese study published in the Journal of Clinical Periodontology aimed to evaluate the association between PD and CRC by examining all existing studies that assess PD and CRC risk. From their analysis, PD was associated with a 44% increase in risk for developing CRC. These findings establish an association, but further studies will be needed to assess any causal relationship between PD and CRC.
Periodontal disease, Fusobacterium, and CRC development
Fusobacterium nucleatum normally lives in the human oral cavity and is commonly associated with periodontal disease. It is one species of bacteria that has been widely studied – its presence has been confirmed in and around CRC tumours (primary and metastatic), as well as other diseases such as cardiovascular disease, arthritis, and Alzheimer’s disease. Numerous investigations have confirmed high levels of other bacteria such as Bacteroides, Prevotella, Leptotrichia, Clostridium difficile, Streptococcus gallolyticus, Bacteroides fragilis, Enterococcus faecalis, Campylobacter spp., Escherichia coli, and Streptococcus bovis in CRC compared to normal healthy tissue, and F. nucleatum has been found to be synergistically associated with other bacteria to promote the incidence and development of CRC7. Specifically, it is implicated in CRC tumours’ ability to proliferate and evade immune attack. Patients with CRC have higher levels of F. nucleatum compared to the general population, and the higher the levels, the worse the prognosis.
The scientific data support the possibility of an association between periodontal disease and the development of CRC through the action of F. nucleatum, though the exact role of this specific bacterium in CRC progression remains an ongoing debate. Findings from future studies that investigate the relationship between periodontal disease and CRC could be important for both periodontal and gastrointestinal practice, integrating periodontal and CRC screening as part of a more comprehensive cancer screening regimen.
Take away message:
Various studies have shown that disease of the gums and the bones that surround and support our teeth (periodontal disease) has been associated with an increased risk of developing colorectal cancer (CRC). Whether periodontal disease causes CRC is not known, though some studies have pointed to the presence and action of a bacterium, Fusobacterium nuleatum, as one of the possible links between periodontal disease and the increased risk of developing CRC.
 Periodontal disease, tooth loss and colorectal cancer risk: Results from the Nurses’ Health Study
 Targeting programmed Fusobacterium nucleatum Fap2 for colorectal cancer therapy
Wu, J.; Li, Q.; Fu, X. Fusobacterium nucleatum Contributes to the Carcinogenesis of Colorectal Cancer by Inducing Inflammation and Suppressing Host Immunity. Transl. Oncol. 2019, 12, 846–851.
 Could periodontal disease through periopathogen Fusobacterium nucleatum be an aggravating factor for gastric cancer?