A. Esophageal gland-like cancer, which occurs predominantly in Europe and North America, is associated with obesity, stomach acid reflux, and is three-to-four times more common in men. The initial lesion, called Barrett’s esophagus, does not cause symptoms. It precedes the cancer and can be seen with the endoscope. When detected, and depending on its severity, Barrett’s esophagus can be treated—either with medications or via endoscopic interventions—to prevent its progression to gland-like cancer.
However, 80-90% of patients with gland-like cancer are diagnosed because of the symptoms alone and without the knowledge of pre-existing Barrett’s esophagus. In the US, 17,000 cases of esophageal gland-like cancers occurred in 2014, causing 15,000 deaths.
As for risk factors, persons with weekly-to-daily heartburn symptoms have five-to-seven times more esophageal gland-like cancers than those who have less frequent symptoms. Unfortunately, 40% of those diagnosed with esophageal gland-like cancer do not suffer from any heartburn. Smokers have twice as many occurrences of cancers than nonsmokers. The rising incidence of esophageal gland-like cancer in the west is attributed to the rising incidence of obesity with its associated acid-reflux disease.
Chronic stomach bacterial infection of H. pylori reduces gland-like esophageal cancer by 40%, presumably by causing stomach gland atrophy, which reduces the production of acid. (Fortunately, treating stomach H. pylori infections—because they can cause stomach cancer and duodenal ulcers—does not seem to increase the incidence of esophageal gland-like cancers.)
Reducing stomach acid with effective medicines (such as proton pump inhibitors of which Nexium is a common example) does reduce the incidence of Barrett’s esophagus and of esophageal gland-like cancer.
B. Esophageal skin-like cancer, which occurs predominantly in Asia, Africa, South America and among Afro-Americans, is associated with drinking alcohol and smoking, accounts for 90% of esophageal cancers world wide, and is equally distributed between men and women. It is three-to-five times more common among heavy smokers and drinkers, its incidence rising progressively with the intensity of smoking and drinking. Moreover, those who have achalasia—a disease that causes spastic narrowing of the esophagus—have ten times more risk of developing esophageal skin-like cancer.
The initial lesion, which precedes the cancer and can be detected with the endoscope, is called squamous dysplasia. The risk of esophageal skin-like cancer increases progressively with the microscopic severity of the dysplasia.
C. Prevention, detection, and treatment: Aspirin and other anti-inflammatory medicines reduce the incidence of both skin-like cancer and gland-like cancer by about 40-50% and are recommended for cancer prevention in certain high-risk groups.
Unlike screening colonoscopy, which is recommended for persons over fifty, screening endoscopy is not recommended for the early detection of esophageal cancers because the incidence is relatively low. The absolute risk of esophageal cancer after age of fifty is about 0.04% per year, which means that 2500 persons will need to be scoped to detect one cancer. Nevertheless, when endoscopy happens to lead to the early detection of esophageal cancer, the results of treatment and overall survival are much better than when cancers are diagnosed after symptoms begin.
Symptoms of esophageal cancer include progressive difficulty in swallowing, as food seems to get stuck in the chest instead of going down to the stomach. Initially, only solid foods prove hard to swallow, but soon after, even soft foods begin to go down with difficulty. This leads to unintended weight loss as patients start to avoid eating. Heartburn that does not respond to effective treatment should also be regarded with suspicion.
Around 75% of gland-like cancers are found in the distal esophagus whereas skin-like cancers commonly occur in the mid or upper esophagus. Treatment can be administered via the endoscope if the cancers are detected very early. More advanced cancers, however, require major surgery and chemotherapy. In the US, the overall five-year survival rate is about 17%. However, when cancers are detected after they have metastasized, the five-year survival rate may be as low as 4%.