Barrett's Esophagus (cont.)
Bhupinder Anand, MD
Wilfred M. Weinstein, MD
In this Article
What about the cancer that occurs in Barrett's esophagus?
Adenocarcinoma of the esophagus
The type of cancer that occurs with Barrett's esophagus is adenocarcinoma. Cancer arising from the squamous lining of the esophagus is called squamous cancer or carcinoma. Among Caucasians, the rate (frequency over time) of squamous cancer is decreasing relative to Barrett's-associated adenocarcinoma. Other racial groups (for example, African Americans) however, have not experienced the same rate of decline in squamous cancer relative to adenocarcinoma.
Smoking and excessive alcohol ingestion are definite risk factors for squamous cancers. They also are risk factors for adenocarcinoma seen in Barrett's esophagus. In this situation, however, it is not clear if smoking and alcohol increase the risk for adenocarcinoma by making GERD more severe or if smoking and alcohol have a more direct cancer-causing effect, as occurs in squamous cancer. Forty years ago, when a patient was diagnosed with cancer of the lower esophagus, it was almost always of the squamous type. Now, in white males, the chances are that 50% or more of the lower esophageal cancers are adenocarcinomas of the esophagus or gastroesophageal junction.
Throughout the remainder of this section, the term esophageal cancer will refer to adenocarcinoma arising from the Barrett's esophagus.
Connection with cancer of the gastroesophageal junction (cardia)
Cancer of the gastroesophageal junction is also called cardia cancer because the region where the esophagus meets the stomach is called the cardia. This cancer, like Barrett's-associated adenocarcinoma, is found predominantly in white males, is apparently increasing in frequency at the same rate as esophageal cancer, and is associated with chronic GERD. Therefore, it has been speculated that cardia cancer starts from short segments (for example, 1-2 cm) of Barrett's. By the time the diagnosis of cancer is made, however, the tumor may have spread beyond the short segment of Barrett's and may appear to be in the cardia. This speculation about the origin of cancer of the cardia, however, remains to be proven.
Increasing cases of Barrett's-associated cancer and cancer of the cardia
An increase in the frequency of esophageal adenocarcinoma has been observed for at least 20 years, primarily in white males. One clue to the reason for this trend may be related to a decrease in the frequency of H. pylori infection of the stomach. In other words, people with Barrett's cancer, including cardia cancer, seem to have lower rates of H. pylori infection than others of the same age and sex in the same population.
H. pylori is the bacterium that is a major cause of ulcers. It is a very common infection worldwide and causes no symptoms in the vast majority of affected people. However, about 10% of persons with H. pylori develop peptic ulcer of the stomach and duodenum. These ulcers are treated by eliminating the bacteria, which in turn, prevents relapse of the ulcers.
If H. pylori goes untreated, it causes progressive inflammation of the stomach (gastritis) which is associated with reduction in acid secretion and possibly less reflux of acid into the esophagus. In many areas of the world, however, this infection is decreasing in frequency, presumably because of better public health measures. Therefore, it is possible that the protective effect (such as decreased acid production) of chronic H. pylori infection has decreased. In other words, with less H. pylori gastritis, the stomach produces more acid and there is more acid to reflux into the esophagus. At the same time, we are more predisposed to reflux in our senior years. So, although this is not a settled issue, the decreasing frequency of H. pylori infection may be one reason for the increasing frequency of Barrett's-associated adenocarcinoma.
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