Abstract Background: Areca nut and tobacco are established etiological agents of oral carcinogenesis. They are used in combination with each other, though their combined effect is very common in South and Southeast Asia and is thought to have a synergistic genotoxic effect. Field cancerization, whereby genetically modified normal mucosa occurs, is a phenomenon that is important in the initiation and progression of oral squamous cell carcinoma. Aim: To determine the effects of dual areca nut and tobacco consumption on field cancerization of the oral mucosa through measuring cytological changes and genomic stability in clinically normal oral mucosa, and to compare the changes with those of single-habit users and non-users. Materials and Methods: The cross-sectional study was developed in three groups ( n = 60 each) of dual users of areca nut and tobacco, single-habit users, and non-users. The samples of exfoliative cytology were obtained by swabbing the buccal mucosa that was considered clinically normal. Micronucleus (MN) assay and cytomorphometric analysis were done. Genomic interest focuses on TP53 and CDKN2A changes and a composite score of genomic instability (GI). Such statistical tests as analysis of variance, chi-square, and Pearson correlation were employed. Results: Dual users showed a much higher ratio of MN frequency (19.4 + 6.1 in 1000 cells) than that of single-habit users (12.1 + 4.7) and controls (4.3 + 2.0) ( P < 0.001). TP53 and/or CDKN2A changes were observed in 61.7%, 33.3%, and 6.7% of dual users, single-habit users, respectively, and controls. There was a significant positive relationship between the frequencies of MN and the score of GI ( r = 0.62, P < 0.001). Conclusion: Simultaneous use of areca nut and tobacco induces significant cytological and genomic changes of clinically normal oral mucosa, which proves the existence of a strong field cancerization effect and the necessity of specific surveillance of high-risk groups.
Parekh et al. (Tue,) studied this question.