Natural History, Incidence, and Mortality
Risk Factors

Natural History, Incidence, and Mortality

Annually, it is estimated that 16,470 Americans will be diagnosed with esophageal cancer, and 14,280 will die of this malignancy.[1] Of the new cases, it is estimated that 12,970 will occur in men and 3,500 will occur in women.

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 over 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.[2] 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.[3] 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),[4] 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.[5-7]

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.[8] The intestinal-type epithelium of Barrett esophagus has a characteristic endoscopic appearance that differs from squamous epithelium.[9] Dysplasia in Barrett epithelium represents an alteration of the columnar epithelium that may progress to invasive adenocarcinoma.[10]

An interesting hypothesis relates the rise in incidence of esophageal adenocarcinoma to a declining prevalence of Helicobacter pylori infection in Western countries. Reports have suggested that gastric infection with H. pylori may protect the esophagus from GERD and its complications.[11] According to this theory, H. pylori infections that cause pangastritis also cause a decrease in gastric acid production that protects against GERD.[12] Patients whose duodenal ulcers were treated successfully with antibiotics developed reflux esophagitis twice as often as those in whom infection persisted.[13]

Past use of lower esophageal sphincter (LES)-relaxing drugs was positively associated with risk of esophageal adenocarcinoma. Among daily, long-term users (>5 years) of LES-relaxing drugs, the estimated incidence rate ratio was 3.8 (95% confidence interval [CI], 2.2–6.4) compared with persons who had never used these drugs. Gastric cardia adenocarcinoma and esophageal squamous cell carcinoma were not associated with use of LES-relaxing drugs.[14]

There exists a strong relationship between body mass index (BMI) and esophageal adenocarcinoma. The adjusted odds ratio (OR) was 7.6 (95% CI, 3.8–15.2) among persons in the highest BMI quartile compared with persons in the lowest. Obese persons (those with BMI >30 kg/m²) had an OR of 16.2 (95% CI, 6.3–41.4) compared with the leanest persons (BMI <22 kg/m²). Esophageal squamous cell carcinoma was not associated with BMI.[15]

References

1. American Cancer Society.: Cancer Facts and Figures 2008. Atlanta, Ga: American Cancer Society, 2008. Also available online. Last accessed October 1, 2008. 
   
   
2. Blot WJ, McLaughlin JK: The changing epidemiology of esophageal cancer. Semin Oncol 26 (5 Suppl 15): 2-8, 1999.  [PUBMED Abstract]
   
   
3. Devesa SS, Blot WJ, Fraumeni JF Jr: Changing patterns in the incidence of esophageal and gastric carcinoma in the United States. Cancer 83 (10): 2049-53, 1998.  [PUBMED Abstract]
   
   
4. Oesophagus. In: World Cancer Research Fund., American Institute for Cancer Research.: Food, Nutrition and the Prevention of Cancer: A Global Perspective. Washington, DC: The Institute, 1997, pp 118-129. 
   
   
5. Lagergren J, Bergström R, Lindgren A, et al.: Symptomatic gastroesophageal reflux as a risk factor for esophageal adenocarcinoma. N Engl J Med 340 (11): 825-31, 1999.  [PUBMED Abstract]
   
   
6. Wijnhoven BP, Tilanus HW, Dinjens WN: Molecular biology of Barrett's adenocarcinoma. Ann Surg 233 (3): 322-37, 2001.  [PUBMED Abstract]
   
   
7. Skacel M, Petras RE, Gramlich TL, et al.: The diagnosis of low-grade dysplasia in Barrett's esophagus and its implications for disease progression. Am J Gastroenterol 95 (12): 3383-7, 2000.  [PUBMED Abstract]
   
   
8. Spechler SJ, Goyal RK: The columnar-lined esophagus, intestinal metaplasia, and Norman Barrett. Gastroenterology 110 (2): 614-21, 1996.  [PUBMED Abstract]
   
   
9. Van Dam J, Brugge WR: Endoscopy of the upper gastrointestinal tract. N Engl J Med 341 (23): 1738-48, 1999.  [PUBMED Abstract]
   
   
10. Reid BJ, Blount PL, Rubin CE, et al.: Flow-cytometric and histological progression to malignancy in Barrett's esophagus: prospective endoscopic surveillance of a cohort. Gastroenterology 102 (4 Pt 1): 1212-9, 1992.  [PUBMED Abstract]
    
    
11. O'Connor HJ: Review article: Helicobacter pylori and gastro-oesophageal reflux disease-clinical implications and management. Aliment Pharmacol Ther 13 (2): 117-27, 1999.  [PUBMED Abstract]
    
    
12. Graham DY, Yamaoka Y: H. pylori and cagA: relationships with gastric cancer, duodenal ulcer, and reflux esophagitis and its complications. Helicobacter 3 (3): 145-51, 1998.  [PUBMED Abstract]
    
    
13. Labenz J, Blum AL, Bayerdörffer E, et al.: Curing Helicobacter pylori infection in patients with duodenal ulcer may provoke reflux esophagitis. Gastroenterology 112 (5): 1442-7, 1997.  [PUBMED Abstract]
    
    
14. Lagergren J, Bergström R, Adami HO, et al.: Association between medications that relax the lower esophageal sphincter and risk for esophageal adenocarcinoma. Ann Intern Med 133 (3): 165-75, 2000.  [PUBMED Abstract]
    
    
15. Lagergren J, Bergström R, Nyrén O: Association between body mass and adenocarcinoma of the esophagus and gastric cardia. Ann Intern Med 130 (11): 883-90, 1999.  [PUBMED Abstract]
    
    

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