People with a history of periodontal disease may have a higher risk of developing oesophageal (gullet) and gastric (stomach) cancer, according to researchers at the Harvard T.H. Chan School of Public Health, who noted that this risk also was higher among people who had previously lost teeth.
Previous findings on the relationship between periodontal disease and tooth loss with oesophageal and gastric cancer have been inconsistent, said the researchers, who examined periodontal disease, tooth loss, and oesophageal and gastric cancer in 98,459 women in the Nurses’ Health Study (1992-2014) and 49,685 men from the Health Professionals Follow-up Study (1988-2016).
The researchers assessed dental measures, demographics, lifestyle, and diet using follow-up questionnaires. Self-reported cancer diagnoses were confirmed after reviewing medical records. During 22 to 28 years of follow-up, there were 199 cases of oesophageal cancer and 238 cases of gastric cancer.
A history of periodontal disease was associated with a 43% and 52% increased risk of oesophageal cancer and gastric cancer, respectively. Compared to people with no tooth loss, the risks of oesophageal and gastric cancer for those who lost two or more teeth were also higher at 42% and 33% respectively.
Among individuals with a history of periodontal disease, no tooth loss, and losing one or more teeth were equally associated with a 59% increased risk of oesophageal cancer compared to those with no history of periodontal disease and no tooth loss. Similarly, the same group of individuals had 50% and 68% greater risk of gastric cancer, respectively.
The researchers point to possible reasons for an association between oral bacteria and oesophageal and gastric cancer, with other studies suggesting that Tannarella forsythia and Porphyromonas gingivalis, members of the “red complex” of periodontal pathogens, were associated with the presence or risk of oesophageal cancer.
Another possible reason is that poor oral hygiene and periodontal disease could promote the formation of endogenous nitrosamines known to cause gastric cancer through nitrate-reducing bacteria, the researchers said.
This was an observational study, so no firm conclusions could be drawn about cause and effect, the researchers said, and they cannot rule out the possibility that some of the observed risk may be due to other unmeasured confounding factors.
Yet the researchers conclude that the findings show the importance of the oral microbiome in these cancers. Further studies directly assessing the oral microbiome may identify specific oral bacteria responsible for this relationship, the said. Also, additional findings could serve as readily accessible and noninvasive biomarkers to help individuals at high risk for these cancers.
The study, “Periodontal Disease, Tooth Loss, and Risk of Oesophageal and Gastric Adenocarcinoma: A Prospective Study,” was published by Gut.