Esophageal cancer is the cancer of the lining of the esophagus, the hollow canal by which food and liquid passes from the throat to the stomach. Esophageal cancer typically develops in the innermost tissue lining the esophagus and extends outward toward the muscular layer. The disease may spread to other parts of the body including the lungs, vocal cords, liver, intestines, and kidneys.
Squamous cell carcinoma is the most common of the two types of esophageal cancer; this type of malignant cell may be caused by exposure to asbestos and other environmental risk factors. The disease affects the thin, flat squamous cells in the esophagus and accounts for almost 90 percent of all esophageal cancer cases. Adenocarcinoma is the other type of esophageal malignancy, developing in the tissue found in the lower part of the esophagus where it attaches to the stomach. Often this form of the disease is caused by reoccurring stomach reflux, a condition that causes stomach acid to back up into the bottom of the esophagus leading to a cellular change that develops into a condition called Barrett's esophagus.
Esophageal Cancer Risk Factors
There are a number of risk factors linked to esophageal cancer including age, alcohol consumption, tobacco use, and exposure to environmental toxins such as asbestos. Esophageal cancer may be caused by frequent contact with high levels of asbestos, according to one review of asbestos morbidity over several years. Tradesmen in the electrical, plumbing, steel, insulation and other similar industries may be at the greatest risk of developing esophageal cancer linked to asbestos. Asbestos fibers in the body generally cause scarring – which is a characteristic of esophageal cancer caused by accidental ingestion of caustic substances such as lye or common dry cleaning fluid, industrial materials that can be ingested in minute amounts by workers.
The clinical study compared the incidence of digestive and esophageal cancer among 2,024 people known to have experienced occupational exposure to asbestos, compared to the incidence of these cancers in the general population. The statistics showed increased levels for both types of cancer among patients with a background of asbestos exposure, leading the researchers to conclude that there is a possible connection between asbestos exposure and the risk of esophageal cancer among men.
Symptoms of Esophageal Cancer
In the early stages of esophageal cancer, there are few symptoms which often leads to a late diagnosis reducing chances of survival. Although treatment results have improved in recent years, the five year survival rate for the disease is still just twenty percent. Once they materialize, symptoms may vary depending on where the malignant cells are located. Some common symptoms during the advanced stages of the disease include:
- Dyshpagia (difficulty swallowing)
- Odynophagia (painful swallowing)
- Coughing up blood
- Severe weight loss
- Pain in the throat and behind the sternum (breastbone) or between the shoulder blades
- Anemia (iron deficiency)
- Esophageal Cancer, National Cancer Institute, http://www.cancer.gov/cancertopics/types/esophageal
- Esophageal Cancer Prevention, Anderson Cancer Center, http://www.mdanderson.org/patient-and-cancer-information/cancer-information/cancer-types/esophageal-cancer/index.html
- Occupational Asbestos Exposure & Digestive Cancers, Alimentary Pharmacology & Therapeutics, Morlais et al, 2009, http://www.medscape.com/viewarticle/706615
- Key Statistics Cancer of the Esophagus, American Cancer Society, http://www.cancer.org/Cancer/EsophagusCancer/DetailedGuide/esophagus-cancer-key-statistics