The American Cancer Society estimates 16,470 new cases of esophageal cancer will be diagnosed in the U.S. this year. About 14,280 men and women will die from the disease. The cancer is more common in older people. Roughly 75 percent of patients are between 55 and 85 at the time of diagnosis. Men are affected three to four times more often than women.

An important risk factor for esophageal cancer is Barrett's esophagus. In this condition, the normal cells lining the esophagus are replaced by abnormal cells. It's caused by chronic exposure of the tissue to stomach acid from gastroesophageal reflux disease (GERD). The American Cancer Society estimates people with Barrett's esophagus have 30 to 100 times the risk of developing esophageal cancer.

Esophageal Screening

People with Barrett's esophagus need to be followed regularly to watch for signs of cellular changes that may indicate development of esophageal cancer. Currently, screening is done through a procedure called an upper endoscopy. Patients are given a sedative to promote relaxation. Then, a thin, flexible tube with a light and camera (called an endoscope) is placed down the throat. As the endoscope is pushed down the throat, doctors take pictures of the walls of the esophagus, looking for suspicious areas. The physician can pass tiny surgical instruments through the endoscope to treat small abnormalities or remove tissue samples for biopsy.

An alternative to upper endoscopy is wireless endoscopy (sometimes referred to as capsule endoscopy, or the "pill cam"). A miniature camera and wireless transmitter are encased in a capsule. Once the capsule is swallowed, it begins taking colored pictures, snapping about two images/second. The data is transmitted to a receiving device/recorder worn on the belt. Eventually, the capsule completes its passage through the digestive tract and is eliminated with the rest of digestive waste. All of the images in the receiving unit can be downloaded to a computer and analyzed by a physician.

A Tethered Capsule

The pill cam is easier for patients than a standard endoscopy. However, it is more costly and not always covered by insurance. In addition, it only provides a one-pass look. If a physician wants to take a second look at an area, the patient must either use another capsule or have the traditional endoscopy.

Researchers at the University of Washington are now developing a form of capsule endoscopy that uses a tether, or thin cord, attached to a capsule. The new capsule contains a scanner and laser light and is a little smaller than the pill cam. Once the capsule is swallowed, an electric current is passed through the cord, causing the illuminating fiber to swing back and forth, in a spiral motion. A miniature camera captures images one pixel at a time. The information is processed and a computer creates a two-dimensional color picture. Scientists say the new device can create up to 15 color pictures per second.

While the traditional pill cam provides only one pass through the digestive system, the movement of the tethered endoscope can be controlled by the physician. The cord enables a physician to bring the capsule up or down as many times as necessary to get more information or clarify images. The device may also be used to reach other parts of the body that are currently hard to reach with traditional endoscopes, like the pancreas.

The tethered endoscope is still in development. Preclinical trials are expected to begin later this year. Eric Seibel, Ph.D., is on the research team developing the device. If testing goes well, the device could be on the market in a few years. He says the ease of use and potential low cost may make the tethered endoscope a useful tool for widespread screening. However, if a suspicious abnormality is detected, patients will still need to undergo traditional endoscopy for doctors to obtain a biopsy.

For information about endoscopy:

American Gastroenterological Association

National Institute of Diabetes and Digestive and Kidney Diseases

For information on GERD or Barrett's Esophagus:

American College of Gastroenterology

For general information on esophageal cancer:

American Cancer Society

National Cancer Institute