Is toombak a risk factor for oral leukoplakia and oral squamous cell carcinoma ? A systematic review

Abstract

Introduction: Toombak is a form of smokeless tobacco that is not well known in Western Society but is widely used by the Sudanese population and many others in the sub-Sahara region. However, unlike other smokeless tobacco products, information on the carcinogenic potential of toombak is scarce. The present review explored any potential epidemiological association between the use of toombak and oral leukoplakia and oral squamous cell carcinoma (OSCC). Methods: Databases including the Web of Science, SCOPUS, EMBASE and PubMed were searched for literature on the potential association between toombak and oral leukoplakia and OSCC. The search also included grey literature. The search period extended from 1990 to 2018. Following data mining, the study selection was conducted by two reviewers independently. Results: Eight studies that satisfied the inclusion criteria were included. Based on these results, there was a threefoldto sevenfold increased risk of developing the oral leukoplakia and oral squamous cell carcinoma among toombak users compared with non-users. Conclusion: Based on the results of the systematic review, there is a strong epidemiological evidence to suggest toombak to be a major risk factor for both oral leukoplakia and OSCC. Further studies are necessary to evaluate the molecular pathway of toombak-induced oral carcinogenesis.