JUL 05, 2017

'Sponge on a String' Detects Esophageal Cancer

WRITTEN BY: Xuan Pham

It looks like a small pill attached to a long string. But scientists say the so-called “pill” may replace traditional endoscopy tests because can easily collect cells and tissues from the throat and esophagus to screen for cancer.

Acid reflux is one of the most common conditions, experienced by more than 60 million Americans every month. It occurs when food, drink, or stomach acid leaks back into the esophagus, causing heartburn and other unpleasantries.

However, a far more serious consequence of acid reflux is esophageal cancer, which can have a high mortality rate when the disease goes unnoticed until the late stages. And this happens more often than it should, as the cancer is difficult to spot and so goes undiagnosed until too late. Cancer of the esophagus makes up about 1 percent of all cancers diagnosed in the United States.

Conventional screening for esophageal cancer is done with endoscopies - procedures that involve putting a camera down patients’ throats to look and collect for cancerous tissues. Aside from causing anxiety in patients, endoscopies carry risk for infection, over-sedation, and perforation of the esophagus lining.

Researchers at the University of Cambridge thought there had to be a better way to screen for esophageal cancer. They developed the ‘cytosponge’ - a pill that transforms into a sponge once swallowed into the stomach. Then, because the pill/sponge is attached to a string, the sponge can be pulled back up. This action allows ample esophageal cells and tissues to be collected in the sponge, which can be used for cytogenetic testing.

“The trouble with Barrett’s oesophagus is that it looks bland and might span over 10cm,” said Professor Rebecca Fitzgerald, the study’s lead investigator. “We created a map of mutations in a patient with the condition and found that within this stretch, there is a great deal of variation amongst cells. Some might carry an important mutation, but many will not. If you’re taking a biopsy, this relies on your hitting the right spot. Using the Cytosponge appears to remove some of this game of chance.”

Because the improved screening process involves swallowing a pill, it is much easier for patients to get continually monitored for the development of cancer. “It would be good news for patients if the cytosponge test could be used to replace uncomfortable endoscopies for some people,” said Jessica Kirby, Cancer Research UK's senior health information manager.

“We know very little about how you go from pre-cancer to cancer – and this is particularly the case in oesophageal cancer. Barrett’s oesophagus and the cancer share many mutations, but we are now a step closer to understanding which are the important mutations that tip the condition over into a potentially deadly form of cancer,” added Caryn Ross-Innes, a study co-author.

Additional sources: University of Cambridge