Head and neck cancers are a group of related neoplasms that arise in the oral cavity, pharynx, and larynx. Almost 600000 new cases of head and neck cancer and 300000 deaths occur worldwide each year. At least 75% of head and neck cancers diagnosed in Europe, the United States, and other industrialized regions are attributable to the combination of cigarette smoking and alcohol drinking. Most cancer in the head and neck is squamous cell carcinoma (HNSCC) and the majority is oral squamous cell carcinoma (OSCC). Worldwide, 25% oral cancers are attributable to tobacco usage (smoking and/or chewing), 7–19% to alcohol drinking, 10–15% to micronutrient deficiency, and more than 50% to betel quid chewing in areas of high chewing prevalence. Cancer of the oral cavity and pharynx is the first and third commonest cancer in Asian men and women, respectively. Whereas in most areas at high risk for cancer of the oral cavity other than India (e.g., central and Eastern Europe, South America). Public awareness about the risk factors and methods of early detection of oral cancer are quite low. Tobacco and alcohol users over age 40 are at highest risk for this disease but often do not appreciate their own heightened risk status, and do not take advantage of community head and neck cancer screenings when they are offered. It was estimated that 4.9 million people died of tobacco-related illness in the year 2000, and by 2020s that figure will rise to 10 million deaths per year, 70% of which will be in developing countries.
In the US some 25% of the population smoke, while in the UK the adult smoking rates are currently around 27% and 38% Australians are smokers. Many other countries have high rates of smoking, but the highest reported rates are from China; a national study in 1996 reporting that 63% of males were current smokers. About half of all regular cigarette smokers will eventually be killed prematurely by their habit.
Figure 1. Diagrammatic summary of Oral Cancer (Oral Squamous Cell Carcinoma: OSCC) risk factors.
Figure 2. Countries with high incidence and mortality from oral cancer.
Figure 3. A comparison of incidence of oral cancer among European populations.
Table 1. Carcinogens in cigarette smoke.
|
Aromatic hydrocarbons
|
Phenolic compounds |
| Benz(a)anthracene |
Catechol |
| Caffeic acid |
Caffeic acid |
| Benz(a)pyrene |
|
| Dibenzo(a)pyrene |
|
| N-Nitrosamamines |
Volatile hyrdrocarbons |
| N-Nitrosodimethylamine |
Benzene |
| N-Nitrosoethylmethylamine |
Nitrobenzene |
| N-Nitrosonornicotine |
|
| Aromatic amines |
Organic compounds |
| 2-Toluidine |
Ethylene oxide |
| 2-6-Dimethylaniline |
Propylene oxide |
| 2-Naphthylamine |
Vinyl chloride |
| Aldehydes |
Metals and metal compounds |
| Formaldehyde |
Arsenic |
| Acetaldehyde |
Nickel |
| |
Chromium |
| |
Cadmium |
| |
Lead |
| |
Radio-isotopes |
| |
Polonium-210 |
Sustained and intensive educational programs on tobacco use resulting in cessation have shown a substantial fall in the incidence of oral leukoplakia in intervention cohorts in India. Outreach programmes from hospitals can educate communities about dangers of tobacco use when combined with oral examinations for the detection of oral precancer. So far in the industrialised countries there have been no specific interventional programs reported. Dentists are uniquely placed to impact smoking rates but need further training and oral physicians and surgeons who manage red and white patches of the oral mucosa frequently fail to address this issue in a systematic way. The oncologist’s role in smoking prevention to prevent second primary tumours is gaining attention.
References and Figures adapted from Scully and Bagan (2009), Oral Oncology, 45(4-5), 301-308; Warnakulasuriya, Oral Oncology (2009), 45 (4-5), 309-316; World Health Organization. Addressing the Worldwide Tobacco Epidemic through Effective Evidence-Based Treatment. Expert Meeting March 1999, Rochester, Minnesota, USA. Tobacco Free Initiative, WHO 2000; Yang et al., Smoking in China. Findings of the 1996 National Prevalence Survey, JAMA 282 (1999), 1247–1253; Warnakulasuriya et al, Oral Oncology (2005), 41 (3), 244-260.
