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The gastrointestinal tract is the second most common noncutaneous site for cancer and the second major cause of cancer-related mortality in the United States.
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INCIDENCE AND ETIOLOGY
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Cancer of the esophagus is a relatively uncommon but extremely lethal malignancy. The diagnosis was made in 16,640 Americans in 2010 and led to 14,500 deaths. Worldwide, the incidence of esophageal cancer varies strikingly. It occurs frequently within a geographic region extending from the southern shore of the Caspian Sea on the west to northern China on the east and encompassing parts of Iran, Central Asia, Afghanistan, Siberia, and Mongolia. Familial increased risk has been seen in regions with high incidence, though gene associations are not yet defined. High-incidence "pockets" of the disease are also present in such disparate locations as Finland, Iceland, Curaçao, southeastern Africa, and northwestern France. In North America and western Europe, the disease is more common in blacks than whites and in males than females; it appears most often after age 50 years and seems to be associated with a lower socioeconomic status.
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A variety of causative factors have been implicated in the development of the disease (Table 38-1). In the United States, esophageal cancer cases are either squamous cell carcinomas or adenocarcinomas. The etiology of squamous cell esophageal cancer is related to excess alcohol consumption and/or cigarette smoking. The relative risk increases with the amount of tobacco smoked or alcohol consumed, with these factors acting synergistically. The consumption of whiskey is linked to a higher incidence than the consumption of wine or beer. Squamous cell esophageal carcinoma has also been associated with the ingestion of nitrites, smoked opiates, and fungal toxins in pickled vegetables, as well as mucosal damage caused by such physical insults as long-term exposure to extremely hot tea, the ingestion of lye, radiation-induced strictures, and chronic achalasia. The presence of an esophageal web in association with glossitis and iron deficiency (i.e., Plummer-Vinson or Paterson-Kelly syndrome) and congenital hyperkeratosis and pitting of the palms and soles (i.e., tylosis palmaris et plantaris) have each been linked with squamous cell esophageal cancer, as have dietary deficiencies of molybdenum, zinc, selenium, and vitamin A. Bisphosphonates may increase the risk in patients with Barrett's esophagus. Patients with head and neck cancer are at increased risk of squamous cell cancer of the esophagus.
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