The role of areca nut ("betel nut") in the global epidemiology of oral cancer

Abstract

Introduction: Melanesia has the highest incidence of oral cancer in the world, with an age standardised rate (ASR) of 31.5 in males and 20.2 for females, compared to the second highest rates in South Central Asia with 12.7 for males and 8.4 for females (IARC 2002). Associated risk factors include tobacco, alcohol, micronutrient deficiencies and HPV, while in Australia melanoma of the lips contributes significantly. Of particular interest is the role of "betel nut" consumption on the incidence of precancerous and cancerous lesions of the mouth. Interestingly carcinogenesis appears to be mediated via a pathway different from the anti-apoptotic p53 protein that is commonly mutated in non-areca induced oral cancers (Thomas et al., 1994). The topographic distribution of areca-mediated carcinogenesis (buccal mucosa, corner of the mouth and cheek) also varies from non-endemic western oral cancer distribution which occurs predominantly at the base of the tongue and alveolar ridge. Betel nut chewing is a widespread indigenous practice in much of the Asia-Pacific region and is particularly prevalent in PNG where 20 80% of the population chew, compared with 10 36% in India and SE Asia. In many countries betel chewing appears to be on the decline with only the elderly or isolated tribes maintaining the habit. However of concern is an increasing trend among younger users and emigrants from countries who take up the habit or transfer it as a sign of rebellion or nationalism. Commercial availability of various betel nut concoctions may also entice a greater number of users. Methods and Material: A review of current ethnographic literature identified regional variability in betel consumption practices. Histologic specimens from East Timor and Kiribati were evaluated for oral malignancies during 2003 to 2006. Results: We will present oral cancer data from East Timor and Kiribati as a baseline representation of oral cancer incidence from 2003 to 2006. This represent two regions, one where betel chewing is endemic the other not. Discussion and Conclusion: We need to understand the pattern and spread risk behaviours worldwide if we are to effectively prevent oral cancer associated with betel nut consumption.