Epidemiology, etiology and prevention of oral cancer

Oral cancer is a major global health problem and familiarity with its epidemiological and etiological characteristics and the methods of prevention has the potential to improve its management. The most common histological subtype of oral cancer is oral squamous cell carcinoma (OSCC), which exceeds 95% of all cases and represents the sixth most common malignancy worldwide. The global incidence varies widely from region to region. An extremely high incidence of OSCC is recorded in India, which is attributed mainly to special local smoking habits, while the incidence in northern Europe is significantly lower than in other counties. OSCC occurs mainly in men aged older than 65 years, although during the last few decades a steadily increasing incidence has been noted among females and individuals of less than 40 years. The most common site of involvement is the lateral border of the tongue, followed by the floor of the mouth. Numerous risk factors have been implicated in the development of OSCC, in a multifactorial model. Smoking is the most significant predisposing factor, especially when combined with heavy alcohol consumption. Human papilloma virus (HPV), especially the oncogenic types 16 and 18, has been implicated in the development of OSCC, but its specific role is still under investigation. In recent years promising molecular biology research has been focused on deciphering genetic aberrations commonly identified in OSCC. Unfortunately, even today, most patients are diagnosed when the OSCC is at an advanced stage, associated with a poor prognosis. Greater emphasis on primary (avoidance of etiological factors) and secondary (early detection) prevention programs is required in order to improve overall survival.