|LETTER TO EDITOR
|Year : 2010 | Volume
| Issue : 5 | Page : 105-107
Temporal role of tobacco in oral carcinogenesis: A hypothesis for the need to prioritize on precancer
Former Prof. Nair Hospital Dental College, 49 Hughes Rd, Mumbai - 400 007, India
|Date of Web Publication||9-Jul-2010|
D K Daftary
Former Prof. Nair Hospital Dental College, 49 Hughes Rd, Mumbai - 400 007
|How to cite this article:|
Daftary D K. Temporal role of tobacco in oral carcinogenesis: A hypothesis for the need to prioritize on precancer. Indian J Cancer 2010;47:105-7
Over past 30 years, I had been an integral part of a team working on Oral Precancer and Cancer at the Basic Dental Research Unit of Tata Institute of Fundamental Research. The time and place allowed us to do extensive clinical work in Mumbai, and in rural India. Our publications. , are a testimony to the quantum and nature of our work. Presented in this article is the gist of my tryst with the human oral precancer and cancer, especially with regard to the tobacco habit, and its real modus operandi.
Our subject tally in 30 years comprised over 200,000 persons in rural India, 50,000 among them being closely followed on a yearly basis for 10 years. The Oral Leukoplakia Register was established among these 50,000 villagers in 5 districts of India. We gleaned there understanding that oral cancer is always preceded by precancer and always precipitated by the tobacco habit. We encountered cancer only in a tobacco habituι. The link seemed to be akin to the one described by the Royal College of Physicians of London, linking tobacco and lung cancer published in 1962. 
The follow-up studies showed a natural spontaneous regression of Leukoplakia (total or partial) varying from 26.1 to 43.7%. Our team on one hand and Pindborg on the other were the first to report on this.
Later, another insight emerged from our studies, and many a study elsewhere, in India. Now and again, oral cancer managed to spring up in a person with no record at all, of any direct or indirect brush with tobacco. That such dissociation between the so-called carcinogen and cancer can also occur was realized.
Although the relative risk of tobacco-associated oral cancer is significantly high, the occurrence of oral cancer in nonhabituιs is also a reality. Studies on cancers occurring in individuals without habits would lead to deep insight into the so-called cause of cancer. The results of these studies would become relevant when strategies directed toward the control of tobacco-related oral cancer bear fruit.
Earlier, some cytologic studies revealed that any carcinogen had only one effect on the target cells, namely, that the target cell's lifespan was foreshortened at the end of which the cell went the way it was inherently preprogrammed to, mostly lysis through apoptosis, and occasionally cancer. All carcinogens should then be regarded as merely aging a cell faster. A carcinogen can be thus regarded as a preponer of a programmed event. 
The tobacco-cancer link in the oral cavity cannot be denied. Abjuring the tobacco habit in a person with healthy oral mucosa or one with dysplastic changes allows the person to postpone the preponement of the probable cancerous change. Probability is a state of knowledge greater than ignorance and lesser than certainty. Nobody can say with certainty which tobacco habituι will develop cancer, or which confirmed nonhabituι will fall a prey to cancer. So cancer in the most avid tobacco user also is a mere probability. But even that probability is dangerous. And hence, it pays to give up tobacco at any stage in one's life. A small price to pay. A big gain to be assured.
The cardinal fact of the spontaneous or instructed reversibility of precancer, and the absolute irreversibility of a fait accompli cancer is the heart of this communication compelling us all to profitably prioritize our attention on oral precancer, rather than end up with only palliation of obstinate cancer.[Figure 1],[Figure 2],[Figure 3],[Figure 4],[Figure 5],[Figure 6]
| » References|| |
|1.||Daftary DK, Murti PR, Bhonsle RB, Gupta PC, Mehta FS, Pindborg JJ. Oral precancerous lesions and conditions of tropical interest. In: Prabhu SR, Wilson DF, Daftary DK, Johnson NW, editors. Oral Diseases in the Tropics. Oxford: Oxford University Press; 1992. p. 402-28. |
|2.||Daftary DK, Murti PR, Bhonsle RB, Gupta PC, Mehta FS, Pindborg JJ. Oral squamous cell carcinoma. In: Prabhu SR, Wilson DF, Daftary DK, Johnson NW editors. Oral Diseases in the Tropics. Oxford: Oxford University Press; 1992. p. 429-58. |
|3.||Royal College of Physicians of London: Report on smoking in relation to cancer of the lung and other diseases. London: Pitman, 1962. |
|4.||Alexander P. Is there a relationship between aging, the shortening of life-span by radiation and the induction of somatic mutations? In: Shock NW. editor. Perspectives in experimental gerontology. Springfield, Illinois: CC Thomas; 1966. p. 266. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]