Pill on a string pulls early signs of cancer

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The Cytosponge is around the same size as a multi vitamin pill(Credit: University of Cambridge)

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As with every form of the deadly disease, early detection of oesophageal cancer is critical to recovery. The current approach of detecting the cancer through biopsy can be a little hit and miss, so the University of Cambridge's Professor Rebecca Fitzgerald and her team have developed what they claim to be a more accurate tool for early-diagnosis. Billed as "a pill on a string," the Cytosponge is designed to scrape off cells from the length of the oesophagus as it is yanked out after swallowing, offering up a much larger sample for inspection of cancer cells.

According to Fitzgerald, the five-year survival rate for oesophageal cancer is only 13 percent, a fact which has led researchers to hunt for signs of a condition that precedes the disease, known as Barrett's oesophagus. This sees the cells located in the lining of the oesophagus take on a different shape and grow abnormally, a process that is brought about by acid and bile reflux when fluids from the stomach come up to say hello. Between one and five of every 100 people with Barrett's oesophagus go on to develop oesophageal cancer.

Using biopsies to detect the pre-cancer condition is problematic for a couple of reasons. It requires trained scientists to pore over the samples looking for abnormalities, which introduces a degree of subjectivity and possible human error. And although a stretch of oesophagus affected by Barrett's could measure as much as 10 cm (4 in), there is much variation in the cells with some presenting mutations and others appearing normal and healthy. This means if the wrong area is targeted, the biopsy may not really reveal much at all.

So Fitzgerald and her team developed a solution they say can provide more accurate results. The Cytosponge is around the same size as a multi vitamin pill, but instead of nutrition it packs a tightly compressed sponge. The patient swallows the capsule just like any other and it makes its way to the stomach, where it rests for around five minutes. In this time the exterior dissolves and the sponge expands. With a string attached and in the nurse's hand, the sponge is then pulled up through the oesophagus. Rather than taking samples from only a section, it scrapes along the entire length of the tube collecting as many as half a million cells in the process.

"If you’re taking a biopsy, this relies on your hitting the right spot," says Fitzgerald. "Using the Cytosponge appears to remove some of this game of chance."

The researchers are hopeful the Cytosponge could replace expensive and invasive endoscopies. Already more than 2,000 patients have swallowed the device in testing, though more trials are required to establish its efficacy. The have licensed the device to a company called Covidien with a view to developing a commercial test.

The team's latest research into Barrett's oesophagus and oesophageal cancer was published in the journal Nature Genetics.

You can hear more from Fitzgerald in the video below.

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