Periodontal Disease May Be Linked To Increased Risk Of Pancreatic Cancer

Those with high levels of antibodies against bacteria associated with gum disease could be more than twice as likely to develop pancreatic cancer as those with low antibody levels according to the results of a new study published online this month in the journal Gut.

While the study doesn’t directly implicate poor oral health and periodontal disease with pancreatic cancer it does raise the possibility that maintaining good oral hygiene could lower an individuals chances of developing pancreatic cancer.

The study, condicted by researchers from Europe and the USA, involved 405 pancreatic cancer cases and 416 matched controls from the EPIC study. The research team measured levels of 25 bacteria commonly found in the mouth. They found that individuals with high levels (>200 ng/mL) of antibodies to a strain of Porphyromonas gingivalis, a type pf bacteria commonly associated with periodontal disease, had 2.14 times increased odds of having pancreatic cancer compared to those with low levels (< 200 ng/mL) of the antibodies. The researchers also found that the presence of high levels of commensal or "good" bacteria slashed the odds of developing pancreatic cancer by almost a half. Previous studies have already suggested a link between periodontal disease and pancreatic cancer. A study of more than 50,000 US male health professionals, published in 2007, found that periodontal disease was associated with an overall 64% increase in pancreatic cancer risk and a 109% increased risk in non-smokers. While periodontal disease is not yet an established risk factor for pancreatic cancer, if larger studies produce similar findings it would join a small group of risk factors for the disease that includes: pancreatitis, diabetes, morbid obesity, cigarette smoking, and high consumption of red and processed meats. Cigarette smoking is considered the biggest risk factor for pancreatic cancer with heavy smokers around 3 times more likely to develop the disease than non-smokers. Cigarette smoking is though to be responsible for about 25% of all pancreatic cancer cases. There are several potential mechanisms that might explain the link between periodontal disease and pancreatic cancer. First, periodontal disease is generally associated with increased levels of several inflammatory markers. Chronic inflammation has been suggested as a potential promoter of carcinogenesis. Second, individuals with periodontal disease have higher levels of nitrate reducing bacteria in their oral cavities. These bacteria convert nitrate into nitrite. Nitrites combine with naturally occurring amines in the body to produce nitrosamines. Most nitrosamine compounds are considered to be carcinogenic and are believed to play a role in the development of a variety of cancers including gastric, esophageal, and pancreatic cancer. Finally, individuals with poor oral health often have a poor diet consisting of a low intake of fruit and vegetables and a high intake of meat. This particular dietary pattern has been linked to an increased risk of pancreatic cancer in some studies. The incidence of periodontal disease in the USA has been slowly declining since the 1970's, mainly due to declines in cigarette smoking and the fluoridation of water supplies. Around 8% of adults aged 20-64 and 17% of adults aged 65+ currently have periodontal disease. Graph of changes in cancer mortality over the past 20 yearsPancreatic cancer is the fourth most common cause of death in both men and women in the USA, accounting for around 6% of all cancer deaths. Pancreatic cancer 5-year survival rates remain stubbornly low at around 4%, mainly due to a large percentage of tumors being detected at an advanced stage and limited treatment options when complete surgical resection is not possible.

As can be seen from the graph to the right, unlike other common forms of cancer, which have seen mortality declines of between 10-40% over the past two decades, the age adjusted mortality rate for pancreatic cancer has remained largely unchanged.