From Our 2015 Archives
Unusual Capsule Could Help Spot Esophagus Cancer
By Clint Witchalls
Reviewed by Arefa Cassoobhoy, MD, MPH
July 21, 2015 -- Swallowing a capsule sponge on a string could help doctors detect a condition called Barrett's esophagus -- and the cancer that can result from it -- much more accurately than current methods, according to a new study in Nature Genetics.
People with chronic (long term) acid reflux sometimes get Barrett's, in which the normal tissue lining the esophagus (the tube carrying food from the mouth to the stomach) changes to tissue that resembles the lining of the intestine. This puts people at risk of getting cancer of the esophagus, or esophageal adenocarcinoma.
When doctors accurately spot Barrett's, they can closely watch their patients for signs of cancer.
Most cases of Barrett's go undetected, though. And by the time people are diagnosed with cancer of the esophagus, it's often too late to save them. Most people (about 80%) with this type of cancer die within 5 years of being diagnosed.
But if Barrett's esophagus is spotted early, it can often be effectively treated.
Sponge on a String
The device is called a Cytosponge, and it looks like an oversized vitamin pill attached to a piece of string. Professor Rebecca Fitzgerald and colleagues at the University of Cambridge developed it.
A patient swallows the capsule while a health care professional holds on to the piece of string. After about 5 minutes, when the capsule has been dissolved by stomach acids, it releases a sponge.
The health care professional then slowly pulls the sponge up the patient's esophagus and out of their mouth. As the sponge passes through, it scrapes cells off the lining of the esophagus. These cells can then be sent to a lab for analysis.
But instead of a pathologist looking at the cells under a microscope, the researchers at the University of Cambridge suggest that DNA analysis of the cells can accurately pinpoint cancerous and precancerous cells. Mutations in the DNA form a pattern that acts as a kind of fingerprint to help identify the disease.
5 Years Away
Earlier studies of the Cytosponge have shown that it's safe and well-tolerated by patients.
This latest study shows that the device gives a much better sample of tissue cells than the current method. An endoscope biopsy takes a few pinpoints of tissue, which can easily miss the diseased cells.
Fitzgerald says she hopes that screening with the Cytosponge will be available in the next 5 years.
For now, people with Barrett's esophagus are usually referred to a gastroenterologist, who will do a procedure called an upper endoscopy. A thin flexible tube with a camera and light at the tip (an endoscope) is lowered down the patient's throat. Bits of tissue are removed from the lining of the esophagus so they can be checked for signs of change in a laboratory.
A pathologist looks at the tissue samples under a microscope to determine if the cells are healthy or not.
This procedure is usually repeated at intervals to watch people who have Barrett's for changes. It can be distressing and expensive, and the results are not always highly accurate.
SOURCES: Ross-Innes, CS. Nature Genetics, July 20, 2015. Kadri, SR. BMJ, 2010. Action Against Heartburn.