at the rate of about one cancer per 100,000 per year, whereas the incidence is high in southern China (30-50 per 100,000 per year), among Eskimos in the Artic region, and among some indigenous populations in Southeast Asia. The risk is 2-3 times higher in men than in women. Risk factors include Epstein-Barr virus (Mueller 1995), consumption of salted fish (Miller et al. 1996), and occupational exposure to formaldehyde (IARC 1995). There are three histologic types: keratinizing squamous-cell carcinoma, non-keratinizing carcinoma, and undifferentiated carcinoma.
Carcinoma of the hypopharynx is an uncommon disease. Considered collectively with carcinomas of the cervical esophagus, they make up about 10% of all tumors of the upper respiratory tract and digestive tract and less than 1% of all cancers diagnosed in the United States each year (Pfister et al. 2004). By far the most common histology is squamous-cell carcinoma. Cervical esophageal squamous-cell cancer and hypopharyngeal cancer typically present as extremely advanced disease, and 5-year survival is about 17-30%. Standard therapy for advanced disease is a combination of chemotherapy and radiation (Lefebvre et al. 1996). The major risk factors for