Link between periodontitis and tongue cancer

Researchers at the University at Buffalo and Roswell Park Cancer Institute have shown for the first time that an association exists between long-standing periodontitis, or gum disease, and risk of tongue cancer.

The study found that the risk of tongue cancer due to chronic gum disease increased five-fold with every millimeter of alveolar bone loss -- the bone in the jaws that hold teeth in place. The association existed even in the absence of a history of smoking.

Results of the study appear in the May issue of Archives of Otolaryngology - Head and Neck Surgery.

Mine Tezal, D.D.S., Ph.D., assistant professor in the Department of Periodontics and Endodontics, UB School of Dental Medicine, and research scientist at Roswell Park Cancer Institute, is first author.

"We expected to see an association, given the results of earlier studies linking chronic infections and inflammation to cancer risk in other organs," said Tezal, "but we didn't expect to see such a clear association with a relatively small sample size.

"If this association is confirmed in larger studies with a broader population and in other oral cancer sites, it will have a significant impact on our understanding of the causes and origin of oral cancer, as well as its prevention and control."

The study compared panoramic (full mouth) dental X-rays of 51 white males newly diagnosed with tongue cancer with records of 54 white males without cancer. All patients were seen in the Department of Dentistry and Maxillofacial Prosthetics at Roswell Park Cancer Institute between June 1999 and November 2005. Persons less than 21 years of age, those with no teeth, and those with a history of any type of cancer, cancer therapy, oral pre-cancerous lesions, immunodeficiency or autoimmune disorders were excluded from the study.

Measurements of alveolar bone loss in all patients were made by the same periodontist, who did not know the cancer status of study participants. After eliminating in the analysis the potential effects of age, smoking status, and number of existing teeth, persons with chronic gum disease were 5.2 times more likely to have tongue cancer with every millimeter of bone loss than those without gum disease, Tezal and colleagues found. Other conditions involving the teeth -- decay, filings, crowns and root canals -- had no significant effect on the incidence of tongue cancer, results showed.

"Periodontitis is a chronic disease that progresses very slowly," said Tezal. "Seeing alveolar bone loss on X-rays indicates the infection has existed for decades, making it clear that periodontitis preceded the cancer diagnosis, and not vice-versa.

"The link between chronic inflammation and cancer has been suspected for many years," she noted. "Even without proof of an inflammation-cancer link, non-steroidal anti-inflammatory drugs (NSAIDs) and other cyclooxygenase (COX) inhibitors have been suggested as chemo-preventive agents against cancer. "Chronic inflammation has been associated with cell proliferation, cell survival, cell migration and angiogenesis, all of which promote tumor development. To determine these roles more specifically in oral cancers, future studies with more participants and more sensitive clinical diagnoses are needed to generate more complete answers."