Oral and oropharyngeal cancers in North India

Sore or Swollen Lips Part 2: Systemic Causes

This series of three papers reviews the causes, diagnosis and differential diagnosis, and outlines the management of sore and/or swollen lips. Clinical relevance: Sore and/or swollen lips are not uncommon, often have a local cause, but may reflect a systemic disease. The previous article reviewed important causes, from actinic to contact cheilitis, while this paper starts with drug-induced cheilitis and completes that alphabetical list.

Epidemiology of cancer by tobacco products and the significance of TSNA

Globally, oral cancer is one of the ten common cancers. In some parts of the world, including the Indian subcontinent, oral cancer is a major cancer problem. Tobacco use is the most important risk factor for oral cancer. The most common form of tobacco use, cigarette smoking, demonstrates a very high relative risk--in a recent cohort study (CPS II), even higher than lung cancer. In areas where tobacco is used in a smokeless form, oral cancer incidence is generally high. In the West, especially in the U.S. and Scandinavia, smokeless tobacco use consists of oral use of snuff. In Central, South, and Southeast Asia smokeless tobacco use encompasses nass, naswar, khaini, mawa, mishri, gudakhu, and betel quid. In India tobacco is smoked in many ways; the most common is bidi, others being chutta, including reverse smoking, hooka, and clay pipe. A voluminous body of research data implicating most of these forms of tobacco use emanates from the Indian subcontinent. These studies encompass case and case-series reports, and case-control, cohort, and intervention studies. Collectively, the evidence fulfills the epidemiological criteria of causality: strength, consistency, temporality, and coherence. The biological plausibility is provided by the identification of several carcinogens in tobacco, the most abundant and strongest being tobacco-specific N-nitrosamines such as N-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). These are formed by N-nitrosation of nicotine, the major alkaloid responsible for addiction to tobacco. The etiological relationship between tobacco use and oral cancer has provided us with a comprehensive model for understanding carcinogenesis.

New approaches to the causation and prevention of cancers of epithelial surfaces

Environmental rather than genetic factors appear to be responsible for the causation of cancers involving epithelial surfaces, especially oropharyngeal cancers, cancers of the gastro-intestinal tract, cancers of the liver and gall-bladder, cancers of the cervix uteri and lung cancers. Epithelial surfaces which have mucus-bearing cells are particularly prone, because if these mucus cells are surrounded by an alkaline milieu over a prolonged period, the mucous of the epithelial cells is rendered fluid and is removed from the cells, of which it forms an integral part. This leads to proliferative changes with metaplasia, cell-atypia and a very significant increase in mitotic activity. Such changes are a prelude to carcinogenesis. In the case of many oropharyngeal cancers in Asia and Africa it is the alkaline slaked lime in the betel quid which is responsible; in the case of gastric cancers it is the reflux of the alkaline duodenal contents into the stomach; in the case of colon it is the absence of roughage, cellulose and vegetable fibres from the diet; in the case of the cervix uteri it is the frequency of coitus which gives rise to a highly alkaline seminal fluid; and in the case of cancer lung it is the alkaline cigarette smoke.

Oral cancer in 57,518 industrial workers of Gujarat, India: a prevalence and followup study

In Gujarat, India, 57,518 industrial workers over 35 years old were examined for oral lesions. At a two-year interval, 43,654 workers were re-examined. Biopsies were taken from 13,223 lesions. In the initial examination, 29 oral cancers were diagnosed, representing a prevalence rate of 50/100,000. After two years, 22 new oral cancers were diagnosed, representing an incidence rate of 25/100,000 per year. Over 90% were squamous carcinomas, with the majority of lesions occurring in the oropharynx and tongue. All patients who developed squamous carcinomas had tobacco habits, while 85% of the entire study population had oral habits in some form. Their most common habits were smoking tobacco alone or in combination with chewing "pan"/"supari." Of the carcinomas that developed during a two-year interval, 62% appeared in previously normal appearing mucosa. Leukoplakia was the only oral lesion that proved to be precancerous, with a transformation rate of 0.13% in a two-year interval.