Gum infections tied to increased risk of stomach cancer precursor

(Reuters Health) - Gum infections may increase people’s risk for sores in the digestive tract that can lead to stomach cancer, a small study suggests.

Researchers focused on what’s known as periodontal disease, serious infections in the mouth caused by bacteria in dental plaque. Daily brushing and flossing can prevent gingivitis, the milder form of periodontal disease, but untreated cases can lead to permanent damage to the gums and bone.

The new study involved 35 people with so-called precancerous lesions: abnormal cells or sores in the digestive tract where cancer is more likely to occur compared to normal tissue. The researchers also studied a control group of 70 similar people who didn’t have these lesions.

Overall, 32 percent of people with precancerous gastric lesions had the kind of bleeding during dental exams that is a hallmark of periodontal disease, compared with 22 percent of individuals without precancerous lesions, the study found.

People with gastric precancerous lesions were also more likely to have high levels of several types of bacteria in their mouths that can contribute to periodontal disease.

“These bacteria are commonly found in periodontal pockets and are invasive because they can produce a variety of molecules that can cause damage to host tissue as well as host responses to bacterial colonization, therefore contributing to cancer development,” said senior study author Yihong Li, a researcher at the New York University College of Dentistry in New York City.

“The periodontal pockets are not easy accessible by a regular toothbrush and could serve as a reservoir of bacterial colonization and potentially a source of chronic inflammation and carcinogenic bacterial (growth),” Li said by email.

Many cases of gastric cancer are linked to smoking and eating foods with a lot of salt or preservatives, researchers note in their report in the Journal of Periodontology. Poor oral health has also been tied to these tumors.

The study wasn’t a controlled experiment designed to prove whether or how oral health problems might contribute to stomach cancer, the researchers note. Precancerous lesions also don’t always develop into cancer.

Even so, the findings add to the evidence that periodontal disease may play a role in the development of stomach cancer, said Jean Wactawski-Wende, a researcher at the University at Buffalo who wasn’t involved in the study.

Inflammation may play a role, Wactawski-Wende said by email. Periodontal disease may cause inflammation in the mouth and also contribute to inflammation throughout the body. Some bacteria from the mouth might also travel from the mouth to the gastrointestinal track.

“This study is small and not able to prove causation; however, there is growing evidence that periodontal disease may be associated with certain types of cancer, including GI cancer,” Wactawski-Wende added. “Maintaining good oral hygiene through teeth brushing and flossing and seeing a dentist regularly may be prudent.”

SOURCE: Journal of Periodontology, online November 27, 2017.