The 13th World Conference on Tobacco OR Health

Objective: Screen for oral cancer among Sudanese toombak dippers using two approaches.

Methods: We assessed presence/degree of epithelial atypia among 300 (100 toombak dippers, 100 smokers, 100 non-tobacco users) subjects. 5 patients with oral cancer (OC) were included as controls. Further we examined p53 codon 72 polymorphism in brush biopsies from 180 toombak users/60 controls. 450 formalin-fixed samples (precancers/cancers) were included from Sudan/Scandinavia, UK/USA and Asia. DNA was extracted/genotyped for p53 polymorphism by PCR-RFLP.

Results: In the first approach, and without knowledge of subjects' tobacco exposure, epithelial atypia was ascertained in 29 (assigned as case category, remaining 271 assigned controls). Among the cases, there were 11 (38%) toombak dippers, 14 (48%) cigarette smokers, 4 (14%) non-tobacco users. Epithelial atypia was found in 5 OC. Inflammatory infiltrate was more frequent among smokers/non-tobacco users compared to toombak dippers. Adjusted OR and 95% CI were 3 (0.91-9.7) and 4 (1.2-12.3) for toombak dippers and cigarette smokers, respectively. For the second approach, genotypic frequencies in brush biopsy individuals were similar to those in cancers, precancers and controls. Frequency of homozygous arginine among toombak users was 27% and this did not differ with controls. But, proline homozygosity of 33% in toombak samples was significantly higher than controls (OR=2.23; 95% CI: 1.14-4.35; P=0.02). We propose use of cytological technique for detection/assessment of oral epithelial atypia. Pro/Pro genotype at p53 codon 72 contributes to susceptibility for oral cancer in toombak dippers. p53 codon 72 polymorphism may serve as marker for risk assessment of oral cancer development in toombak users.