Prevention of Esophageal Cancer
Doctors cannot always explain why one person gets cancer and another does not. However, scientists have studied general patterns of cancer in the population to learn what things around us and what things we do in our lives may increase our chance of developing cancer.Anything that increases a person’s chance of developing a disease is called a risk factor; anything that decreases a person’s chance of developing a disease is called a protective factor. Some of the risk factors for cancer can be avoided, but many cannot. For example, although you can choose to quit smoking, you cannot choose which genes you have inherited from your parents. Both smoking and inheriting specific genes could be considered risk factors for certain kinds of cancer, but only smoking can be avoided. Prevention means avoiding the risk factors and increasing the protective factors that can be controlled so that the chance of developing cancer decreases.
Although many risk factors can be avoided, it is important to keep in mind that avoiding risk factors does not guarantee that you will not get cancer. Also, most people with a particular risk factor for cancer do not actually get the disease. Some people are more sensitive than others are to factors that can cause cancer. Talk to your doctor about methods of preventing cancer that might be effective for you.
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Incidence and Mortality of Esophageal Cancer
Annually, approximately 14,250 Americans will be diagnosed with esophageal cancer, and 13,300 will die of this malignancy. Of the new cases, 10,860 will occur in men and 3,390 will occur in women.Two histological types account for the majority of malignant esophageal neoplasms, i.e., adenocarcinoma and squamous carcinoma. The epidemiology of these types varies markedly. In the 1960s, squamous cell cancers comprised over 90% of all esophageal tumors. The incidence of esophageal adenocarcinomas has risen markedly 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. Although the overall incidence of squamous cell carcinoma of the esophagus is declining, this histologic type remains 6 times more likely to occur in black males than in white males. Incidence rates generally increase with age in all racial/ethnic groups. In black men, however, the incidence rate for the 55 to 69 year age group is close to that of whites in the 70 years and older age group. In black women, aged 55 to 69 years, the incidence rate is slightly higher than that of white women in the 70 years and older age group.
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Risk Factors for Esophageal Cancer
While risk factors for squamous cell carcinoma of the esophagus have been identified (such as tobacco use, alcoholism, malnutrition, infection with human papillomavirus), the risk factors associated with esophageal adenocarcinoma are less well 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.An interesting hypothesis relates the rise in the 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. According to this theory, H. pylori infections that cause pangastritis also cause a decrease in gastric acid production that protects against GERD. Patients whose duodenal ulcers were treated successfully with antibiotics developed reflux esophagitis twice as often as those in whom infection persisted. Other factors that have been suggested to explain the increased risk of esophageal adenocarcinoma include obesity and use of medications, such as anticholinergics, that can predispose to GERD by relaxing the lower esophageal sphincter.
GERD is a risk factor for esophageal adenocarcinoma because long-standing GERD is associated with Barrett’s 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’s esophagus has a characteristic endoscopic appearance that differs from squamous epithelium. Dysplasia in Barrett’s epithelium represents a neoplastic alteration of the columnar epithelium that may progress to invasive adenocarcinoma.
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Information adapted from the National Cancer Institute at http://cancer.gov/
