Esophageal Cancer

Disease Background

The esophagus is a hollow tube that carries food and liquids from the throat to the stomach. The esophagus is located just behind the windpipe (trachea). In an adult, the esophagus is about 10 inches long. When a person swallows, the muscular walls of the esophagus contract to push food down into the stomach. Glands in the lining of the esophagus produce mucus, which keeps the passageway moist and makes swallowing easier.

Cancer that begins in the esophagus, or esophageal cancer, is divided into two major types, squamous cell carcinoma and adenocarcinoma, depending on the type of cells that are malignant. Squamous cell carcinomas arise in the flat scale-like cells that line the esophagus. These cancers usually occur in the upper and middle part of the esophagus. Adenocarcinomas usually develop in glandular tissue in the lower part of the esophagus. The treatment is similar for both types of esophageal cancer.

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The American Cancer Society estimates that in 2006 more than 14,000 Americans will be diagnosed with cancer of the esophagus and more than 13,000 will die of the disease. By far, the strongest risk factors for esophageal squamous cell carcinoma are tobacco and alcohol use. Together they account for almost 90 percent of such cancers. A diet lacking fresh fruits and vegetables also increases risk. Studies show that esophageal cancer is more likely to occur as people get older; most people who develop esophageal cancer are over age 60. It is more common in men than in women.

In contrast, the causes of esophageal adenocarcinoma are less clear. While tobacco use increases risk, more important risk factors appear to be the presence of reflux and being overweight.

Tissues at the bottom of the esophagus can become irritated if stomach acid frequently backs up into the esophagus, a problem called gastric reflux. Over time, cells in the irritated part of the esophagus may change and begin to resemble the cells that line the stomach. This condition, known as Barrett's Esophagus, may develop into adenocarcinoma of the esophagus.

Barrett's Esophagus is a precancerous condition arising in 10 to 20 percent of the patients with chronic gastric reflux. People who develop Barrett's Esophagus may have symptoms of heartburn, indigestion, difficulty swallowing solid foods, or nocturnal regurgitation that awakens them from sleep. The normal white lining of the esophagus has been replaced by an abnormal red lining called specialized intestinal metaplasia.

People who have had other head and neck cancers have an increased chance of developing a second cancer in the head and neck area, including esophageal cancer.

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Our Research

Overview of Hutchinson Center Research

Hutchinson Center researchers, in collaboration with colleagues at the University of Washington, are taking a multidisciplinary approach to esophageal cancer through the Seattle Barrett's Esophagus Research Program. The program includes an experienced clinical team caring for patients with Barrett's Esophagus; a laboratory team that is investigating the genetic and cell-cycle abnormalities that lead to cancer in Barrett's esophagus; and epidemiologists who are investigating environmental risk factors that may cause Barrett's esophagus and cancer.

Program members have developed a method for monitoring cancer risk and onset in patients with Barrett's esophagus, a technique that's boosted survival rates for esophageal cancer from 5 percent of more than 80 percent. Other Hutchinson Center scientists are looking to find ways to prevent the occurrence of esophageal cancer by identifying behavior and environmental exposures that correlate with the development of Barrett's and esophageal cancer.

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Uncovering the genetic progression from Barrett's esophagus to esophageal cancer

Cancer arises slowly over time as cells go through a progression of genetic rearrangements that transform normal tissue to malignancy. While studying this evolution in the laboratory is useful, ultimately it is understanding how these changes occur in the human body that holds the key to halting the disease before it begins. Using a common digestive disorder, Barrett's esophagus, Dr. Brian Reid's research team has successfully drawn an outline of the numerous genetic changes that take place as a cell progresses from normal to cancerous.

In about 1 percent of Barrett's patients each year, the condition progresses to a type of cancer called esophageal adenocarcinoma. The course of the disease can be monitored by directly looking into the esophagus using endoscopy. Endoscopy, a procedure in which a slender, flexible fiber-optic tube is inserted through the mouth into the esophagus, allows doctors to obtain small tissue samples, or biopsies, from the esophagus at regular intervals and examine them for malignant growth. Based on thousands of these samples taken over years, Reid and Dr. Peter Rabinovitch, a pathologist at the University of Washington, have begun to unravel the cellular differences that cause this small group of patients to develop cancer.

Using a technique called flow cytometry that illuminates chromosomes in the cell and permits them to be counted, Reid's group has developed a method of monitoring cells from esophageal biopsies and sorting them based on their DNA content. The cells with abnormal amounts can be distinguished from their normal counterparts, allowing for much earlier detection of the progression to cancer.

Reid is also employing new technologies, such as fluorescent genotyping and sequencing as well as single nucleotide polymorphisms (SNP) and gene microarrays, that allow analysis of thousands of genes simultaneously to discover patterns of genetic function that may signal development of cancer at an even earlier stage.

See also the Barrett's esophagus Web site.

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Relevant Articles

• A friend on the front line of fear — Christine Karlsen helps Barrett's esophagus patients by speaking from a place of personal understanding
  
  
• Fighting cancer with NSAIDs — Regular use of aspirin and other nonsteroidal anti-inflammatory drugs may reduce esophageal-cancer risk for people with Barrett's esophagus
  
  
• Evolution of esophageal cancer — New study pinpoints two characteristics that predict whether precancerous Barrett’s esophagus will progress to cancer
  
  
• Selenium: An element of good health — Trace dietary mineral may inhibit progression of Barrett’s esophagus
  
  

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