TOOMBAK DIPPING AND CANCER OF THE ORAL CAVITY IN THE SUDAN - A CASE-CONTROL STUDY

To investigate the possible causal association between squamous-cell c arcinomas of the oral cavity and use of toombak, we retrospectively co mpared the history of use of this substance in 375 patients with squam ous-cell carcinomas of the lip, buccal cavity and floor of mouth, and 271 patients with squamous carcinomas of the tongue, palate and maxill ary sinus, with 204 patients exhibiting non-squamous oral and non-oral malignant neoplasms and 2,820 individuals who had no malignancy, sele cted from the general population. The study revealed that the high pre valence of oral cancer in the Sudan is largely due to chronic use of t oombak. The adjusted ORs associated with toombak dipping for the first case group, cancer of the lip, buccal cavity and floor of mouth in co mparison with the hospital and population control groups, were 7.3 and 3.9 (95% confidence limits, 4.3-12.4 and 2.9-5.3) respectively and am ong long-term users the adjusted ORs were 11.0 and 4.3 (95% confidence limits, 4.8-25.1 and 2.9-6.3) respectively. The elevated risk found w hen investigating intra-oral cancers of sites in direct contact with t oombak quid compared to those with little or no contact, confirms the hypothesis that direct contact with tissues is an important factor in tobacco carcinogenesis in the mouth. The increased risk associated wit h the use of toombak is of particular concern in view of its wide cons umption in the Sudan.