Sponge on string could replace endoscopy in patients with Barrett’s oesophagusBMJ 2016; 355 doi: https://doi.org/10.1136/bmj.i6080 (Published 11 November 2016) Cite this as: BMJ 2016;355:i6080
A pill that expands into a sponge when swallowed could be used by GPs to identify which people with Barrett’s oesophagus have a low risk of developing oesophageal cancer and could avoid the need for endoscopies, researchers at Cancer Research UK have found.1
Determining which patients with Barrett’s oesophagus, which can lead to oesophageal cancer in a small number of people, have a low risk of developing cancer could help to reduce overdiagnosis and overtreatment in this group, said the researchers.
About one in seven people in the United Kingdom has gastro-oesophageal reflux, but referral for endoscopy varies between primary care practices despite guidelines, and low referral rates are linked with poor outcomes from oesophageal cancer. Figures show that the median survival of patients with oesophageal adenocarcinoma is one year, and only 12% of patients survive for 10 years.
To help determine the risk of Barrett’s oesophagus progressing, researchers have developed the “cytosponge”—a small pill with a string attached that the patient swallows and which expands into a small foam sponge when it reaches the stomach. As the sponge is pulled back up, it collects throat cells from the oesophagus for analysis.
Researchers from the University of Cambridge gave 468 people with Barrett’s oesophagus a cytosponge test and tested the collected cells for two specific genetic markers and any changes in the cells that could be used to estimate the risk of developing oesophageal cancer. These results, alongside other information including age and obesity, were used in a mathematical model to classify patients’ risk levels.
The cytosponge test, together with additional laboratory tests, identified that 35% of people in the study (162) were at a low risk of developing oesophageal cancer—defined as having a 100% probability of being a true non-dysplastic patient and a 0% probability of having high grade dysplasia or intramuscular carcinoma.
The lead researcher, Rebecca Fitzgerald, who is based at the MRC Cancer Unit at the University of Cambridge, said, “Most people who have Barrett’s oesophagus will not go on to develop oesophageal cancer, but at the moment there is no way of identifying who will and who won’t. Our study is the first step in using the cytosponge to answer this question.
“We’re assessing the cytosponge test in larger trials next year to understand more about how it can help diagnose oesophageal cancer sooner. Compared with endoscopies performed in hospital, the cytosponge causes minimal discomfort and is a quick, simple test that can be done by your GP.”
A video of the Cytosponge test can be seen at https://www.youtube.com/watch?v=s7X9z6qlNUI.