Risk Factors

• More common in men than women
• More common in blacks than whites
• Age (90% over age 45)
• Tobacco (smoking, chewing, dipping snuff and second-hand smoke)—primary risk factor
• Alcohol
• Ethanol and tobacco together are much worse than either one individually
• Asbestos, nickel, and polyvinyl chloride exposure
• Mustard gas exposure
• Defoliating agents exposure
• Poor oral hygiene (ill-fitting bridgework, broken teeth, mucosa irritated by sharp or jagged teeth)

Lip

• Sun exposure
• Chronic irritation
• Direct contact with tobacco
• Contact with stem of a pipe

Nasopharynx

• Chinese/Asian ancestry
• Epstein-Barr virus exposure
• Familial clusters

Salivary glands

• Prior radiation to the head and neck

Thyroid gland

• More common in women than men
• Most common between ages 25 and 65
• Prior radiation to head and neck in infancy or childhood
• Familial association for medullary carcinoma