About Esophageal Cancer
The esophagus is the hollow tube that connects the throat to the stomach. When a person swallows, the muscular wall of the esophagus contracts to push food and liquid down into the stomach for digestion.To make swallowing easier, glands located in the lining of the esophagus produce mucus, which keeps the pathway moist.
The wall of the esophagus is made up of several layers. Cancer of the esophagus, called esophageal cancer, originates in the inner layer, growing outward.
What are the different types of esophageal cancer?
There are two major types of cancer of the esophagus, squamous cell carcinoma and adenocarcinoma.
The top layer of the lining of the entire length of the esophagus is made up of squamous cells, so squamous cell carcinoma can begin anywhere in the organ. Adenocarcinoma, on the other hand, starts only in the lower part of the esophagus, near the opening of the stomach, where glandular tissue is present. Prior to adenocarcinoma developing, the squamous cells near the opening of the stomach must be altered by acid reflux, as in Barrett’s esophagus [see below].
What are the risk factors for esophageal cancer?
Studies indicate that the following factors raise the risk of developing esophageal cancer:
Tobacco use: Using any kind of tobacco — cigarettes, cigars, pipes or chewing tobacco — is a major risk factor for esophageal cancer.
Alcohol use: Chronic, heavy drinking is another major risk factor for cancer of the esophagus. In people who both drink and smoke, the risk of cancer is especially high. For example, risk increases by 18 times in people who drink more than 13 ounces of alcohol a day for several years. If these same people smoke at least 1–2 packs of cigarettes a day, the risk of esophageal cancer multiplies 44 times.
Barrett’s esophagus: This is a condition characterized by chronic reflux (backward flow) of acidic fluid from the stomach into the lower esophagus. Some people with Barrett’s esophagus experience heartburn from the reflux, but others experience no symptoms and are unaware that they have the condition.Whether or not Barrett’s esophagus has been diagnosed, long-term gastric reflux is a risk factor for adenocarcinoma of the esophagus, because the reflux alters the esophageal cells located near the opening of the stomach.The abnormal cells can develop precancerous changes known as dysplasia, making people with Barrett’s esophagus about 50 times more likely to develop cancer of the esophagus compared to people without the condition. Specifically, about one out of every 100 people with Barrett’s esophagus develops esophageal cancer per year.
Irritation or damage to the esophagus: Besides chronic gastric reflux, other causes of irritation or damage to the esophagus also pose a risk for esophageal cancer. Ingestion of lye — a chemical found in strong household cleaners, such as drain cleaners — can burn esophageal cells. If a child accidentally drinks a cleaning liquid containing lye, the lining of the esophagus will scar, and the child will have a higher risk of squamous cell esophageal cancer.
Diet: A diet deficient in fruits, vegetables, and certain vitamins and minerals, especially vitamins A, C, riboflavin and the mineral selenium, may raise the risk of cancer.Obesity has also been associated with elevated risk.
A history of certain diseases: Three rare conditions — achalasia, esophageal webs and tylosis — raise the likelihood of developing esophageal cancer.
In achalasia, the muscle at the bottom of the esophagus does not relax enough to release food into the stomach. As a result, food collects there, expanding the esophagus and raising the risk of squamous cell carcinoma. Esophageal webs are abnormal pieces of tissue that extend into the esophagus and can make it difficult to swallow. People who have esophageal webs often have problems with the tongue, fingernails, spleen and other organs, a combination of difficulties usually called Plummer- Vinson syndrome but also sometimes called Paterson-Kelly syndrome.
Tylosis is characterized by excess skin growing on the palms of the hands and soles of the feet. For unknown reasons, people with tylosis are very likely to get esophageal cancer and should therefore be screened regularly.
Risk factors for esophageal cancer that we cannot control include age, gender, and race.The cancer is more likely to strike as we age, with a majority of patients developing the disease between the ages of 45 and 70. The disease is also more common in males, afflicting three times more men than women. African Americans are almost three times more likely than whites to be affected.
Can anything be done to prevent esophageal cancer?
Avoiding tobacco use and limiting alcohol consumption are the best strategies for preventing esophageal cancer.
If you suffer from heartburn, talk to your doctor about treating it. There are a number of medications available for preventing gastric reflux.There are also several lifestyle modifications that can help prevent reflux, such as avoiding acidic foods (such as citrus fruits and tomatoes), spicy foods or fatty foods, and avoiding bending over, lying down, or exercising soon after meals.
Because obesity and poor diet have also been tied to esophageal cancer, maintaining a healthy weight and eating more fruits and vegetables may also reduce the risk of the disease. In addition, early studies suggest that taking aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) may help lower the risk of cancer of the esophagus. However, it is too soon to recommend taking aspirin or NSAIDs exclusively for this purpose.
Is there a screening test for esophageal cancer?
There is no routine screening test for the general population. However, there is an early-detection test available for high-risk people, such as individuals with a history of Barrett’s esophagus. The test is an endoscopy, which involves examining the esophagus through a flexible lighted tube called an endoscope. During an endoscopic examination, the doctor can remove a sample of tissue to examine under a microscope for the presence of cancerous cells.This is called a biopsy.
For people with Barrett’s esophagus, endoscopy and biopsies are recommended every 1–3 years, depending on the degree of dysplasia (cell abnormalities) found on the first endoscopic biopsy test. If no dysplasia is found, many doctors recommend endoscopy and biopsies every 2 – 3 years. If low-grade (less severe) dysplasia is present, screening is usually repeated once a year. However, for high-grade (more severe) dysplasia, surgery to remove the area of Barrett’s esophagus is usually recommended.
This is because there is a high likelihood that cancer is already present (even if it is not detected by endoscopy) or will develop soon.
What are the signs and symptoms of esophageal cancer?
Unfortunately, the signs and symptoms of esophageal cancer do not become apparent until the disease has progressed to a late stage. The most common symptom is difficulty swallowing, medically known as dysphagia. (To cause this symptom, a tumor must be large enough to block about half the diameter of the esophagus.) About 50 percent of patients also experience weight loss due to the inability to swallow enough food to maintain their weight. Sometimes, patients experience pain or a burning sensation in the mid-chest region. In people with advanced esophageal cancer, signs and symptoms may also include hoarseness, chronic cough, hiccups, vomiting, pneumonia and high calcium levels in the blood.
If you experience any of these symptoms, contact your physician. The symptoms can be caused by conditions other than cancer, but it is important to see your doctor for an examination.
What tests are used to diagnose esophageal cancer?
If esophageal cancer is suspected, the doctor will use several methods to diagnose the disease beginning with a medical interview to look for risk factors and symptoms, and a physical exam.
The doctor will also order diagnostic tests, starting with a barium swallow. This is a series of upper GI (gastrointestinal) x-rays taken after the patient drinks a liquid containing barium, which coats the inside of the esophagus and shows up on the images to highlight any abnormalities. To further enhance the clarity of a barium swallow, the doctor can do a double-contrast study, in which air is blown into the esophagus to help push the barium toward the esophageal wall, allowing it to better coat the surface.
Another diagnostic test is an endoscopy – see above,“Is there a screening test for esophageal cancer?”
Once esophageal cancer is diagnosed, more tests will be performed to determine the extent of the disease. This is called staging. These tests not only produce images of the esophagus but also of the surrounding organs and nearby lymph nodes (small collections of immune system cells that help fight infections). One such test is a computed tomography scan (CT scan) – a specialized procedure in which a series of x-rays taken at different angles are put together by a computer to create detailed crosssectional images of the body. A second, newer procedure is endoscopic ultrasound in which an ultrasound probe uses sound waves to generate images of the targeted area.
Another staging test is a bronchoscopy – a procedure in which the doctor inserts a bronchoscope (a thin, flexible, lighted tube similar to an endoscope) into the mouth and down through the windpipe (trachea) to determine if cancer has spread to the tubes connecting the trachea to the lungs (the bronchi). If the doctor needs to examine the lymph nodes in the chest and abdomen for signs of cancer, further tests can be done.
What are the stages of esophageal cancer?
The stage of a cancer is the most significant factor when devising a treatment plan. For esophageal cancer, the system usually used to stage the disease is the TNM system (also known as the American Joint Committee on Cancer, or AJCC, system).This system is based on three main variables: “T,” which refers to the size of the tumor;“N,” which describes how far the cancer has spread to nearby lymph nodes; and “M,” which indicates whether the cancer has spread to distant organs in the body or to lymph nodes not located near the esophagus.
The TNM system is used to categorize the cancer in stages 0 through IV (0–4).The higher the stage number, the more the cancer has spread. Some doctors also divide the stages into letters (for example, IIA or IIB) to further clarify the extent of the cancer.
How is esophageal cancer treated?
Treatment of esophageal cancer depends on the type of tumor and the stage of the disease, the condition of the esophagus, and the patient’s age and overall health.The three main treatment methods include surgery, chemotherapy and radiation therapy. A new treatment, photodynamic therapy, is also an option for some patients. Frequently, a combination of treatments is recommended.
The goal of surgery is to remove the cancer and a margin of cancer-free surrounding tissue. Unfortunately, surgery is a cure for esophageal cancer in less than 25 percent of cases. However, it is frequently used to relieve symptoms, particularly dysphagia (difficulty swallowing). Surgery successfully alleviates dysphagia in more than 80 percent of patients.
The two most common surgical procedures are esophagectomy and esophagogastrectomy. In an esophagectomy, the surgeon removes part of the esophagus and nearby lymph nodes, then reconnects the remainder of the esophagus to the stomach. In an esophagogastrectomy, which is used for more severe cancer, the surgeon removes part of the esophagus, nearby lymph nodes, and the upper part of the stomach.The remainder of the stomach is then connected to the upper part of the esophagus.These surgical procedures are often complicated by the need to remove a large part of the esophagus. If this is the case, there are two methods used to reconnect the remaining portion of the esophagus and stomach. In the first, the stomach is simply brought up to esophagus and ends up being located in the upper part of the chest. In the second, a portion of the large intestine is removed and used to replace the missing part of the esophagus.
If chemotherapy (the use of cancer-killing drugs) is recommended, it can be administered by injection into a vein (IV) or by mouth.The drugs enter the bloodstream and travel throughout the whole body, attacking cancer cells found beyond the esophagus.A combination of anticancer drugs is usually used, typically given in cycles (a period of treatment followed by a period of recovery, then another treatment period, and so on). Chemotherapy may be used in three ways. First, it can be given before surgery to shrink the tumor and thereby enable a more complete surgical removal of the cancer. Second, it can be used in combination with radiation therapy in patients who cannot undergo surgery. Third, it can be used to relieve symptoms (called palliative therapy) in late-stage esophageal cancer.
Radiation therapy, in which high-energy rays are used to kill cancer cells, is also used to treat esophageal cancer, usually in combination with surgery and/or chemotherapy. For example, radiation may be administered either before surgery to shrink the tumor or after surgery to destroy any remaining cancer cells. For advanced cancer, radiation therapy may be used to relieve symptoms, particularly dysphagia. In a patient whose overall health is too fragile to undergo surgery, radiation is sometimes used by itself as the main form of therapy.
The most common type of radiation therapy used for esophageal cancer is external beam radiation therapy, which means the radiation is administered from a machine, and the procedure is a lot like having an x-ray. Occasionally, internal radiation therapy (brachytherapy), in which radioactive material is implanted in the esophagus near the cancer, is used. The final treatment option is photodynamic therapy. It involves the injection of a nontoxic chemical into the bloodstream, where it is allowed to circulate and collect in the tumor for a few days.A special laser is then focused on the tumor through an endoscope.The intense light of the laser alters the chemical, transforming it into a toxic drug that can kill cancer cells. More research is needed on photodynamic therapy, but it represents a promising new therapeutic option.