Risk factors for squamous cell carcinoma of the oral cavity in young people--a comprehensive literature review.

There have been several reports of a rising incidence of oral cancer from many parts of the world. Although it is well known that oral cancer increases with age, recent trends for a rising incidence particularly relates to cancer of the tongue and mouth in young males. This review critically examines 46 publications devoted to oral cancer in the young adult. Most studies suggest that 4-6% of oral cancers now occur at ages younger than 40 years. Several studies examining risk factors for oral cancer in the young provide evidence that many younger patients have never smoked or consumed alcohol, which are recognised risk factors in older groups, or that duration of exposure may be too short for malignant transformation to occur. Information on many aspects of aetiology for this disease in the young implicating occupational, familial risk, immune deficits and virus infection are meagre. The spectrum of genetic abnormality disclosed is similar to older patients, there is paucity of specific studies involving younger cohorts, but predisposition to genetic instability has been hypothesised as a likely cause. Conflicting evidence is also reported on the sex distribution and outcome compared with older patients. Much work is required to understand the caveats related to global demography, risk factors and their diagnostic and prognostic markers for this disease which might be considered a disease distinct from that occurring in older patients.