Diagnosis of Barrett's Oesophagus currently requires an endoscopist pushing an endoscope down your throat and taking biopsies from suspect areas to be examined by a histopathologist in the lab. All rather time consuming and expensive (at £600 a time for the NHS).
So doctors are often reticent about referring patients reporting heartburn which is common and usually curable with an antacid or acid suppressant medicine. This may mean patients with pre-cancerous Barrett's may be missed.
Is there an easier (and cheaper) way?
In China, 40 years ago, wanting to see what was going on inside patients complaining of reflux and swallowing problems, a technique was attempted which involved a patient swallowing something the size of a golf ball and regurgitating it. Hardly surprising it didn't catch on, particularly as once regurgitated, doctors had no idea how to interpret whatever was brought up with it.
However in recent years the idea has been reinvented. Squash a sponge ball into a soluble capsule small enough to be swallowed and fastened to a length of string and you have CytospongeTM. The capsule can be swallowed like a tablet whilst keeping hold of the string. The capsule dissolves, the sponge expands and it is pulled back out by the string.
Far left the expanded sponge. To its right the capsule.
Development of the Cytosponge has been carried out by the Cambridge based team led by Dr Rebecca Fitzgerald and funded by Cancer Research UK and the Medical Research Council.
Millions of cells are harvested this way from anywhere between the stomach and the mouth. It is not feasible to start examining them under a microscope as with a normal biopsy so the cells need to be examined in another way.
The complete test kit.
The cells are removed by soaking the sponge in a histological fixative and centrifuging the resultant mass. They are then assessed using a variety of techniques including flowing past a laser in a flow cytometer that identifies cells by the way they scatter the light and looks for specific biomarkers. Biomarkers have been identified that indicate a particular possibility of Barrett's Oesophagus and for Oesophageal cancers.
Flow cytometry is one of the processes used.
If these biomarkers are detected, the patient will require a normal endoscopy for further appraisal.
The advantages of Cytosponge are it is considerably cheaper than an endoscopy (about £25 a time), takes less time, requires less skill (a nurse at a GP practice could administer it) and it could be used as an initial screening for any patient who reports persistent heartburn so more cases of Barrett's may be discovered before it's too late.
Cytosponge is still being trialled. Hopefully it will soon be approved for general use with Covidien ready to market it.