Cytomorphometric Study of Effect of Tobacco Smoking on Buccal Mucosa: A Case control study
Abstract
Tobacco smoking is associated with increasing risk of oropharyngeal cancer. Oral cytology, mainly based on the presence of nuclear or cytoplasmic alterations, can easily be performed to detect cancer at an early stage and provides a quantitative technique. The objective of the present study was to assess the effect of smoking on buccal mucosa using cytomorphometry. This case control study included 36 smoker subjects and 36 non-smoker controls between the age of 30 and 70 years. Buccal epithelial cells were collected with a brush and fixed smears were stained with Papanicolaou stain and cytomorphometric analysis performed using image analysis software (Image J v 1.47). Smoker group was found to have higher mean nuclear diameter (MND), lower in mean Cellular diameter (MCD), and higher nucleo-cytoplasmic ratio as compared to normal subjects. This change in nuclear parameters indicates smoking-related cellular adaptation, leading to progression towards dysplasia. Cytomorphometric changes could prove to be the earliest indicators of these cellular alterations.
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Introduction
Oral cancer is one of the six common cancers in the world1,2 and it is also one of the ten major causes of death across the globe. 3 Tobacco smoking has been associated with increasing risk of oropharyngeal cancer and oral leukoplakia. Most of the oral cancers are preceded by precursor lesion, which could be of great help in early diagnosis. Oral cytology, which is mainly based on the presence of nuclear or cytoplasmic alterations, can easily be performed to detect cancer at an early stage and to establish quantitative techniques. .4
Tobacco is of two main types: Smoked and Smokeless tobacco. Commercially it is available in dried, cured, and natural forms. In India Bidies majorly account for about 40% and Cigarettes about 20% of total consumption followed by Cherrut or Chutta, Chillum, Hukli and Hukkah and rest divided among different forms of chewing tobacco. 5
Many carcinogenic substances, mostly DNA-toxic carcinogens are present in cigarettes which cause genetic mutations and chromosomal abnormalities and micronuclei.
Cytological staining techniques developed by Papanicolaou & Traut is now widely used in the detection of asymptomatic cancers, 6 Recent advancements in the field of quantitative oral exfoliative cytology have lead to evaluation of various parameters such as nuclear size, cell size, nuclear-tocytoplasmic ratio, nuclear shape, nuclear discontinuity and optical density. 7 The two significant morphologic changes known to occur in actively proliferating cells of oral lesions are, decrease in the cellular diameter and increase in the nuclear size. 8
Conclusion
This study concludes that reduction in cell diameter, increase in nuclear diameter and increase in nucleo-cytoplasmic ratio among cytomorphometry finding found in smokers. These findings may be an early indication of malignant change. The association of these cytomorphometric effects with tobacco exposure gives important information about risk assessment process and may be used to assess health risks for exposed persons. The simple, inexpensive and easy cytomorphometric analysis method can make the cytological study of subjects with tobacco smoking habit a more objective and practical tool for the early detection of oral cancer. To further confirm the cytological alterations and its role, further studies are required with prospective design, more sample size and standardized parameters.