Chronic periodontitis and the risk of oral cancer

Morbidity and mortality from oral cancer are high and this has not improved in decades in spite of extensive research. A significant portion of research is concentrated on chemoprevention. However, advances in this field have not translated into a visible change in mortality and morbidity. In addition, existing chemoprevention strategies have two important obstacles: toxicity and reversal of the effects after cessation of treatment. Chronic infection and inflammation have been linked to carcinogenesis in a few organs. For oral cancer, substantial evidence has accumulated for the role of human papillomavirus (HPV). However, the development of an effective preventive vaccine strategy for oral cancer is still years away and the target population is largely unexplored. Therefore, safe and practical additional approaches are necessary to change the status quo of oral cancer. Periodontitis is a chronic oral infection caused by inflammatory reactions in response to gram negative anaerobic bacteria in the endogenous dental plaque. It leads to irreversible destruction of tissues around teeth clinically detectable as periodontal pockets and alveolar bone loss. Periodontal pockets have been suggested as reservoirs of HPV. Chronic proliferation and ulceration of the pocket epithelium may help HPV’s initial infection and persistence. Our preliminary results from existing data at Roswell Park Cancer Institute suggest a robust independent association between the history of periodontitis and incident oral cancer. Our next step is to test the synergy between periodontitis and HPV for the risk of oral cancer. If this is true, it will translate to practical and safe prevention and treatment strategies. This chapter will review the evidence supporting the association between chronic periodontitis and oral cancer as well as HPV-periodontitis synergy.