Esophageal Cancer Diagnosis

  • Diagnosis

    The esophagus is a hollow tube that connects the throat to the stomach. Figure 01 In an adult, the esophagus is approximately ten inches long and about an inch in diameter at its narrowest point. When a person swallows, muscles that line the walls of the esophagus contract, forcing food and liquid into the stomach. Glands in the esophagus produce mucus that lubricates this passageway and makes swallowing easier.

    At either end of the esophagus are special muscular tissues called sphincters. The upper esophageal sphincter opens to allow food and liquid into the esophagus. The lower esophageal sphincter prevents stomach acid from backing up and causing irritation in the esophagus.

    Esophageal cancer is divided into two major types—squamous cell carcinoma and adenocarcinoma—depending on the type of cells that have become cancerous. Figure 02 The walls of the esophagus are made up of several distinct layers. The inner lining of the esophagus is made up of thin, flat cells that resemble fish scales. These cells are called squamous cells, and cancer that begins in this tissue is called squamous cell carcinoma. Glandular cells that secrete mucus are found in a layer deeper in the wall of the esophagus. When these cells become malignant, the cancer is called adenocarcinoma.

    Squamous cell carcinomas generally develop in the upper or middle sections of the esophagus. Adenocarcinomas generally develop is the lower sections of the esophagus.

    The number of cases of esophageal cancer is rising in the U.S. For the year 2001, the American Cancer Society estimates that 13,200 new cases will be diagnosed, and 12,500 people will die from the disease. Although treatments for esophageal cancer are available, the disease is rarely curable, with the overall 5-year survival rate ranging from 5% to 25%.

    Click to enlarge: The esophagus

    Figure 01. The esophagus

    Click to enlarge: The esophagus wall

    Figure 02. The esophagus wall

    The underlying cause of esophageal cancer is not well understood. Several factors, such as smoking and alcohol abuse, have been linked with a higher risk of squamous cell carcinoma of the esophagus, but the exact mechanism by which these risk factors result in cancer is not known. Many scientists believe that alcohol or chemicals in tobacco smoke damage the DNA in the cells lining the esophagus, and it is these mutations that leads to the uncontrolled cell growth characteristic of cancer.

    Long-term irritation to the esophagus, such as that caused by gastroesophageal reflux disease (GERD), can also lead to adenocarcinoma of the esophagus. Almost everyone with adenocarcinoma first has a condition called Barrett's esophagus. This condition is caused by excess esophageal exposure to stomach acid. People who have severe GERD symptoms for many years have a higher risk of Barrett's, especially if they smoke and drink excessively.

    Esophageal cancer usually does not cause symptoms in its early stages. Most people with esophageal cancer don't know they have it until symptoms develop, and these symptoms generally occur only after the cancer is in its advanced stages. This is one of the reasons why five-year survival rates for the disease are so low.

    The most common symptom of esophageal cancer is difficulty swallowing (dysphagia). When the cancer has grown large enough to narrow the esophagus by about half its diameter, it can interfere with swallowing. By this time, the cancer is often too large to be curable. Difficulty swallowing first occurs with solid food, but eventually even swallowing liquids becomes painful.

    As the cancer grows, symptoms may include difficult or painful swallowing, severe weight loss, pain in the throat or back, hoarseness or chronic cough, vomiting, or coughing up blood.

    Weight loss is common with esophageal cancer. About half of the people with esophageal cancer also have unwanted weight loss. Weight loss occurs as the patient stops eating or reduces the amount of solid food that he or she eats. The cancer itself can also cause a loss of appetite or changes in metabolism that result in weight loss.

    Pain in the throat or back, between the breastbones, or between the shoulder blades occurs rarely in esophageal cancer. Although these symptoms occur with esophageal cancer, they also occur with many other common problems such as heartburn, and are often ignored.

    Several risk factors have been identified for esophageal cancer, but there are people who get the disease who have none of the known risk factors.

    As with many other cancers, the risk of developing esophageal cancer increases with age. People under the age of 45 rarely develop esophageal cancer. Most cases occur in men over the age of 60.

    Use of tobacco and chronic or excessive use of alcohol are the major risk factors for esophageal cancer. Tobacco use, either by smoking or chewing, increases the risk of developing esophageal cancer. The longer a person uses tobacco, the higher the risk. Chronic and/or heavy alcohol use is also a risk factor for developing squamous cell esophageal cancer, although probably less so than is the case with tobacco. People who use both alcohol and tobacco have an especially high risk for esophageal cancer, perhaps because the substances may increase each other’s harmful effects.

    Men are three times more likely to develop esophageal cancer than women. This may be in part because men in general drink and smoke more than women do, and both drinking and smoking are risk factors for squamous cell esophageal cancer.

    If stomach acid rises into the esophagus, it irritates the tissues lining the esophagus, and increases a person's risk of developing adenocarcinoma of the esophagus. Chronic gastric reflux is a condition in which the contents of the stomach flow backward into the lower esophagus. Some people with this condition feel heartburn; others have no symptoms. Over time, the irritation caused by the stomach acid causes the cells lining the esophagus to become abnormal, developing into a precancerous state called Barrett's esophagus. People with Barrett's esophagus are about 50 times more likely to develop esophageal cancer as the general population.

    In addition to these major risk factors, several other minor factors increase a person's risk for developing esophageal cancer. These risk factors include swallowing lye or other irritants, genetic conditions such as tylosis (a rare disease that results in excessive growth of the skin on the palms of the hands or soles of the feet), achalasia (a condition in which the lower esophageal sphincter does not open properly), and esophageal webs (abnormal protrusions of tissue into the esophagus).

    Diet may also be a factor. Diets that are high in fat, low in calories, or low in protein may contribute to esophageal cancer. In addition, exposure to substances called nitrosamines—sometimes found in cured meats, dried milk, and beer—may also be a risk factor.

    Your doctor will start by taking a medical history and performing a physical examination. When esophageal cancer is suspected, your physician will ask you to describe your symptoms as well their timing and onset. Your physician will also ask you about risk factors that may apply to you. A physical examination will provide information about any signs of esophageal cancer, as well as other health problems.

    When esophageal cancer is suspected, your physician will order a barium swallow. A barium swallow, also called an esophagram, is a series of x-rays of the esophagus. In the procedure, the patient drinks a liquid containing barium, a dense chemical that absorbs x-rays. The barium coats the inside of the esophagus and makes its shape visible on an x-ray image. The x-ray is then taken, and the image shows any irregularities in the normally smooth surface of the esophagus.

    Your physician may also order an endoscopy to examine the inside of the esophagus. An endoscope is a thin, lighted tube with a video camera on the end. During the procedure, the patient is sedated (so that the tube can pass through the patient's mouth and throat without causing gagging), and the endoscope is inserted into the esophagus. The physician can observe any suspected tumors directly, and can take a biopsy to determine whether the tissue is cancerous, and if so, its type (squamous cell or adenocarcinoma).

    Computed tomography (CT) may be used to determine the extent of the cancer. Esophageal cancer may spread to adjacent organs or to nearby lymph nodes. Neither endoscopy nor a barium swallow can show the spread of the cancer beyond the esophagus wall. A CT scan, by contrast, is performed through a process in which three-dimensional x-ray images are made of the area of the cancer. It can be used to help determine the extent of the spread of the cancer and to determine whether surgery is a good treatment option.

    In some cases, your physician may order an endoscopic ultrasound to stage the cancer. Endoscopic ultrasonography is a newer technique in which an ultrasound wand is inserted into the esophagus. The instrument uses sound waves to penetrate deeply into tissue to determine how much of the tissue next to the esophagus is affected by the cancer. As with the CT scan, this information can be used to determine the extent of the spread of the cancer, and whether or not the tumor is operable.

    If the esophageal cancer has spread, your physician may order a bone scan. A bone scan is a test in which the doctor injects a small amount of radioactive material into one of your veins. The material spreads throughout the body and collects in the bones, especially in areas where the cancer has replaced normal bone tissue. A scanner that can detect the radioactivity is then passed over your body, and an image is created of the areas of the body in which the cancer has spread.

    Other common areas where the cancer can spread include the trachea, nearby lymph nodes, the liver, and the lungs.

    The stage of esophageal cancer is determined primarily by how far it has penetrated into the esophagus or spread beyond the esophagus. The 5-year survival rate for esophageal cancer declines from 60% at Stage I to less than 5% if the cancer spreads to distant organs. It is important for the doctor to determine what stage your cancer has reached in order to begin appropriate treatment.

    • Stage I. The cancer is found only on the top layer of cells lining the esophagus.
    • Stage II. The cancer involves deeper layers of the lining of the esophagus, or it has spread to nearby lymph nodes. The cancer has not spread to other parts of the body.
    • Stage III. The cancer has invaded more deeply into the wall of the esophagus, or has spread to tissues or lymph nodes near the esophagus. It has not spread to other parts of the body.
    • Stage IV. The cancer has spread to distant organs.

    Stop smoking and reduce your intake of alcohol. Smoking and alcohol abuse are risk factors for squamous cell carcinoma of the esophagus. The longer a person smokes, the higher the risk of developing esophageal cancer. People who both drink and smoke are at an especially high risk. Quitting smoking and reducing your intake of alcohol can reduce your risk of squamous cell carcinoma of the esophagus.

    Get tested (and treated, if necessary) for gastroesophageal reflux disease (GERD). GERD is a condition in which stomach acid rises into the esophagus and irritates its cellular lining. Over time, this irritation can make the cells lining the esophagus abnormal, and can lead to adenocarcinoma of the esophagus. People with GERD may feel like they have heartburn, or may have no symptoms at all. Getting tested and treated for GERD can help prevent adenocarcinoma of the esophagus. Most people with GERD do not need an endoscopy, a procedure in which a specialist inserts a tube into the esophagus through the mouth. But people with severe, unrelenting GERD symptoms for several years should have this test done. It is the most effective way to diagnose Barrett's. People who are diagnosed with Barrett's usually need to have a repeat endoscopy every few years to make sure that Barrett's has not progressed to cancer.

    Eat a low-fat, high-protein diet. Avoid substances called nitrosamines, which are sometimes found in cured meats, dried milk, and beer.

  • Prevention and Screening

    Stop smoking and reduce your intake of alcohol. Smoking and alcohol abuse are risk factors for squamous cell carcinoma of the esophagus. The longer a person smokes, the higher the risk of developing esophageal cancer. People who both drink and smoke are at an especially high risk. Quitting smoking and reducing your intake of alcohol can reduce your risk of squamous cell carcinoma of the esophagus.

    Get tested (and treated, if necessary) for gastroesophageal reflux disease (GERD). GERD is a condition in which stomach acid rises into the esophagus and irritates its cellular lining. Over time, this irritation can make the cells lining the esophagus abnormal, and can lead to adenocarcinoma of the esophagus. People with GERD may feel like they have heartburn, or may have no symptoms at all. Getting tested and treated for GERD can help prevent adenocarcinoma of the esophagus. Most people with GERD do not need an endoscopy, a procedure in which a specialist inserts a tube into the esophagus through the mouth. But people with severe, unrelenting GERD symptoms for several years should have this test done. It is the most effective way to diagnose Barrett's. People who are diagnosed with Barrett's usually need to have a repeat endoscopy every few years to make sure that Barrett's has not progressed to cancer.

    Eat a low-fat, high-protein diet. Avoid substances called nitrosamines, which are sometimes found in cured meats, dried milk, and beer.

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