Esophageal cancer is among the top ten most common cancers in the world. It begins in the tissues of the esophagus, the muscular tube that moves food from the throat to the stomach. Tumors usually don’t cause symptoms at first, which makes routine screening very important — something tricky to do when only relying on endoscopy for screening.

Now, a team of UK researchers have come up with a novel solution. They created a capsule sponge, called pill-on-a-thread, to test for Barrett’s oesophagus, a condition that can be a precursor to cancer. Heartburn is a common symptom of Barrett’s oesophagus. A clinical trial has now started to establish how well it works.

The test is used to gather cells from the esophagus. This involves a compact sponge enclosed within a capsule connected to a slender thread, akin in size to a vitamin pill. The patient would swallow the capsule and thread with a glass of water. The capsule then dissolves in the stomach, releasing the sponge. A nurse would then extract it by pulling the thread.

This would allow for cells to be collected from the esophagus during the process. It all takes around 10 minutes — faster than endoscopy, currently used to diagnose and monitor esophageal cancer. It’s already been piloted in the UK with patients on waiting lists for endoscopy and now researchers are at the final stage of testing whether the sponge can detect cancer.

If this is the case, the pill-on-a-thread would become a national screening program in the UK — just like mammograms are used for breast cancer. The first step of the trial, called BEST4 Surveillance, is for people diagnosed with Barrett’s oesophagus. It will look at whether the capsule sponge effectively replaces endoscopy to monitor their condition.

Trial participants will undergo both examinations, and the results will be utilized to evaluate their susceptibility to oesophageal cancer. The upcoming phase of the trial, BEST4 Screening, is set to commence in the summer, aiming to enroll 120,000 individuals aged 55 and over who are undergoing long-term treatment for heartburn.

The trial builds on decades of research by Rebecca Fitzgerald, a professor from the University of Cambridge, who invented and refined the capsule sponge test with a team of scientists, clinicians and nurses from several institutions. They believe the capsule sponge could halve the number of deaths from esophageal cancer every year.

“Cases of esophageal cancer have increased sixfold since the 1990s. On average only 12% of patients live more than five years after diagnosis. Most don’t realize there’s a problem until they have trouble swallowing. By then it is too late,” Fitzgerald said in a news release, optimistic over potential positive from the upcoming trials in the UK.

Most people can resume their daily activities after taking the sponge test. The collected cell samples are sent to a laboratory for analysis, where experts employ specialized stains to examine the samples for potential cell changes. If any cell changes are identified, endoscopy may be recommended to confirm any underlying health issues.

Iain Foulkes, Executive Director of Research and Innovation at Cancer Research UK, said that while around 59% of all esophageal cancers are preventable, taking an endoscopy can be labour-intensive. “We need better tools and tests to monitor people most at risk,” he said in a news release, highlighting the possibilities of the capsule sponge.