Calculating Risk

CURE, Fall 2005, Volume 4, Issue 3

Head and neck cancer is largely caused by lifestyle habits such as heavy tobacco or alcohol use.

While tobacco and alcohol use are the main causes of head and neck cancer, other risk factors include chronic viral infection, sun exposure and inhalation of carcinogenic materials.

Cigarettes are the most common, but cloves and bidis, which are unfiltered, have also been gaining popularity, especially among young users. Although smokers of cigars and pipes never inhale the carcinogens into their lungs, they are still at an increased risk for lip, mouth, tongue, throat and laryngeal cancers. There is also the threat of secondhand smoke from these products, which can cause esophageal and lung cancers.

Chewing betel nut or paan, popular in Southeast Asia, and using smokeless tobacco (snuff and chewing tobacco) also greatly increase the risk of mouth cancer. The use of chewing tobacco has tripled in the past 20 years, with a third of users under 21. Prolonged irritation of the mouth tissues with these carcinogens increases the risk of cancer four-fold when compared with a non-tobacco user.

Epstein-Barr virus (EBV) has been shown to cause nasopharyngeal cancer, while human papillomavirus (HPV) may increase the risk of oropharyngeal cancer and mouth cancer. EBV and HPV are also commonly seen in Hodgkin’s disease and cervical cancer, respectively.

Other causes of nasopharyngeal and laryngeal cancers, in addition to tobacco and alcohol, include prolonged inhalation of asbestos, wood dust, nickel dust and other industrial exposures. Radiation to the head and neck increases the risk of salivary gland cancer.

Risk also increases with age and is more often seen in men than in women. Malnutrition and vitamin deficiency, especially lack of retinoids (vitamin A derivatives) can make a person more susceptible to this type of cancer. It is believed that good oral hygiene helps prevent head and neck cancer. But since a percentage of head and neck cancer patients do not have any major risk factors, genetic factors are being investigated as a cause, though head and neck cancers are not believed to be hereditary.