In 2014, it is estimated that 18,170 Americans will be diagnosed with esophageal cancer, and 15,450 will die of this malignancy. Of the new cases, it is estimated that 14,660 will occur in men and 3,510 will occur in women.
The age-adjusted incidence of carcinoid tumors worldwide is approximately 2 per 100,000 persons.[1,2] The average age at diagnosis is 61.4 years. Carcinoid tumors represent about 0.5% of all newly diagnosed malignancies.[2,3]
Carcinoid tumors are rare, slow-growing tumors that originate in cells of the diffuse neuroendocrine system. They occur most frequently in tissues derived from the embryonic gut. Foregut tumors, which account for up to 25% of cases, arise...
Two histologic types account for the majority of malignant esophageal neoplasms: adenocarcinoma and squamous carcinoma. The epidemiology of these types varies markedly. In the 1960s, squamous cell cancers comprised more than 90% of all esophageal tumors. The incidence of esophageal adenocarcinomas has risen considerably for the past 2 decades, such that it is now more prevalent than squamous cell cancer in the United States and Western Europe, with most tumors located in the distal esophagus. Although the overall incidence of squamous cell carcinoma of the esophagus is declining, this histologic type remains six times more likely to occur in black males than in white males. Incidence rates generally increase with age in all racial/ethnic groups but squamous cell cancer is consistently more common in blacks than in whites. Among black men, the incidence rate for those aged 55 to 69 years is close to that of white men aged 70 years and older. In black women aged 55 to 69 years, the incidence rate is slightly higher than white women aged 70 years and older.
While risk factors for squamous cell carcinoma of the esophagus have been identified (such as tobacco, alcoholism, malnutrition, and infection with human papillomavirus), the risk factors associated with esophageal adenocarcinoma are less defined. The most important epidemiological difference between squamous cell cancer and adenocarcinoma, however, is the strong association between gastroesophageal reflux disease (GERD) and adenocarcinoma. The results of a population-based case-controlled study suggest that symptomatic gastroesophageal reflux is a risk factor for esophageal adenocarcinoma. The frequency, severity, and duration of reflux symptoms were positively associated with increased risk of esophageal adenocarcinoma.[5,6,7]
Long-standing GERD predisposes to Barrett esophagus, the condition in which an abnormal intestinal epithelium replaces the stratified squamous epithelium that normally lines the distal esophagus. The intestinal-type epithelium of Barrett esophagus has a characteristic endoscopic appearance that differs from squamous epithelium. Dysplasia in Barrett epithelium represents an alteration of the columnar epithelium that may progress to invasive adenocarcinoma.