A non-invasive test where the patient swallows a “sponge on a string” could replace endoscopy as a means of diagnosing Barrett’s esophagus – a gullet condition that can lead to cancer.
This was the conclusion of a Cancer Research UK trial that was presented recently at the National Cancer Research Institute (NCRI) Cancer Conference in Liverpool, UK.
The trial evaluated the safety, acceptability and accuracy of the Cytosponge – a minimally invasive cell sampling device that uses a sponge on a string to take samples – in the diagnosis of Barrett’s esophagus.
For the Cytosponge test, the patient swallows a dissolvable capsule with a string attached to it. The capsule contains a cytosponge – a sponge engineered from material with just enough abrasiveness to collect cells without damaging tissue.
When the capsule has dissolved, the doctor or nurse pulls the string to retrieve the sponge, collecting cells on the way. These are then sent to the lab for analysis, like a biopsy sample.
Senior author Rebecca Fitzgerald, a professor based at the Medical Research Council Unit at Cambridge University, says:
“The Cytosponge test is safe, acceptable and has very good accuracy for diagnosing Barrett’s esophagus. It should be considered as an alternative to endoscopy for diagnosing the condition and could possibly be used as a screening test in primary care.”
Barrett’s esophagus results from changes in the cells that line the gullet or foodpipe at the point where it joins the stomach. It is caused by repeated acid reflux – where acid in the stomach comes back up into the foodpipe – which produces symptoms like heartburn and indigestion.
The condition is usually diagnosed via a biopsy – by removing a small sample of tissue – during an endoscopy, which involves pushing a camera and light on the end of a thin tube down into the gullet, often under sedation.
As well as being uncomfortable, the procedure is not without risk, and it is not always practical for patients with acid reflux or heartburn.
Over time, the affected cells can become cancerous, so patients with Barrett’s esophagus need to be regularly checked – typically via endoscopy every 2 years.
The video below demonstrates how the Cytosponge is used to collect cells to test for Barrett’s esophagus:
In the trial, 600 patients with Barrett’s esophagus underwent both a Cytosponge test – where they swallowed a sponge on a string – and an endoscopy. Another 500 people without Barrett’s esophagus, but who were experiencing acid reflux and heartburn, underwent the same two tests.
The results showed that the Cytosponge test was very accurate at diagnosing Barrett’s esophagus. Over 94% of participants managed to swallow the sponge with no serious side effects. Participants who underwent endoscopy without sedation were also more likely to say they preferred the Cytosponge test.
Dr. Julie Sharp, head of health information at Cancer Research UK, says the study is “very encouraging and it will be good news if such a simple and cheap test can replace endoscopy for Barrett’s esophagus.” She adds:
“Death rates are unacceptably high in esophageal cancer so early diagnosis is vital. Tackling esophageal cancer is a priority for Cancer Research UK, and research such as this will help doctors to diagnose people who are at risk quickly and easily.”
Nobody knows exactly how common Barrett’s esophagus is. The US National Institute of Diabetes and Digestive and Kidney Diseases say estimates suggest it affects 1.6-6.8% of people and the average age of diagnosis is 55, although exactly when the condition has started is not easy to diagnose. Men are twice as likely as women to develop Barrett’s esophagus.
In January 2013, Medical News Today reported on another study by a team in the US that is developing a swallowable pill-camera as an alternative to endoscopy.