Study suggests oesophageal cancer 'less common than previously thought' in people with Barrett's oesophagus
In the largest study of its kind, Danish researchers have found that the rates of oesophageal cancer among people with Barrett's oesophagus - a common condition that predisposes to the disease - could be up to four times lower than previous estimates.
The results are in line with another recent study from Northern Ireland, which used a different method. If the new figures are confirmed, it could have implications for the way people with Barrett's oesophagus are monitored in future.
However a UK clinician said that the way the study had been designed could mean its result was an underestimate, and that that the matter was not yet settled.
Barrett's oesophagus is common, affecting around 2 per cent of the UK population. Currently, people with the conditions are offered regular check-ups using an endoscope; however, this is uncomfortable and is not without risk.
Oesophageal cancer affects nearly 8,000 people in the UK each year, and is often diagnosed late. Consequently, the outlook is often poor. The number of people with the disease has been increasing dramatically in recent years.
Although Barrett's oesophagus is one of the strongest risk factors for the disease, only about 5 per cent of patients with oesophageal cancer have previously been diagnosed with Barrett's.
Writing in the New England Journal of Medicine, researchers from the University of Aarhus went back through tissue samples collected at all Danish hospitals between 1992 and 2004.
They identified 11,028 samples from people who were diagnosed with Barrett's oesophagus, and followed up their medical records for an average of 5.2 years, to look for linked cases of oesophageal cancer.
They found 197 cases of oesophageal cancer in total, 131 of which occurred in the first year after the sample was collected, and calculated that the 'absolute annual risk' - the rate at which people with Barrett's oesophagus subsequently developed oesophageal cancer, was 0.12 per cent - far lower than the previous best estimate of 0.5 per cent.
They also calculated that people with Barrett's were 11 times more likely than the general population to develop oesophageal cancer, lower than previous estimates of between 30 and 40 times.
The authors argue that their results, together with other recent analyses of the cost-effectiveness of routine endoscopy and its effect on quality of life, mean that routine screening may not be in patients's best interest, unless abnormal pre-cancerous cells - called dysplasia - are detected.
They wrote, "the results of our study suggest that the risk of [oesophageal cancer] among patients with Barrett's esophagus is so minor that in the absence of dysplasia, routine surveillance of such patients is of doubtful value."
An endoscopy is estimated to cost the NHS around £400.
Dr Rebecca Fitzgerald, a Cambridge-based oesophageal cancer expert said the result, while potentially an underestimate, supported the need for better methods to monitor patients with Barrett's oesophagus.
"This is the largest study of its kind to look at rates of oesophageal cancer among people with Barrett's oesophagus, and its findings are welcome. However, it doesn't give us a final answer. The researchers only used tissue samples to define who did or didn't have Barrett's oesophagus, rather than looking at both tissue samples and endoscopy results. As a result they are likely to have overestimated the proportion of individuals with Barrett's oesophagus and hence it is likely that the cancer risk is an underestimate.
She also pointed out that oesophageal cancer is less of a problem in northern continental Europe than in the UK. Therefore future research will need to establish whether these rates are applicable to other populations.
"Nevertheless, this is a very large, long-term study, and confirms that we urgently need to look for a better method of monitoring people with Barrett's oesophagus rather than endoscopy and biopsy, which is expensive, time-consuming, uncomfortable and not particularly good at predicting which patients are at risk for cancer. Oesophageal cancer is usually detected late when it is difficult to treat. We need to do all we can to spot this disease earlier if we're to make a dent in its survival rates, which have been static for many years."
Dr Fitzgerald is currently trialling a new method of monitoring people with Barrett's oesophagus which, rather than using an endoscope, relies on a 'sponge-on-a-string' that collects cells from the oesophagus. She said the method promises to be cheaper, less invasive and safer.
"It will also involve testing for molecular markers within the cells, rather than relying on looking at them down a microscope, so we hope it will be more accurate at predicting cancer risk too," she added.
Cancer Research UK is funding the trial, which is led from in Cambridge but being carried out at several centres around the UK.
Copyright Press Association 2011