People who treat and forget persistent heartburn using over-the-counter remedies could be putting their lives at risk, according to experts.
Doctors warned that anyone suffering symptoms of acid reflux, or heartburn, continuously for more than three weeks should be investigated for potential oesophageal cancer.
Evidence suggests that obesity and acid reflux are key factors behind rising rates of the disease, one of the deadliest cancers.
In the past 30 years the number of people diagnosed each year with oesophageal cancer in the UK has doubled to around 8,400.
Men are three times more likely than women to develop the disease, which is often diagnosed late and has shocking rates of survival.
Even with the best care, patients only live three months on average and just 13% survive five years or more.
Oesophageal cancer affects the oesophagus, or gullet, that links the throat and stomach.
Experts are still trying to understand what is fuelling the rise in oesophageal cancer, and seeking new ways of tackling it.
The trend is mostly due to one form of the disease called adenocarcinoma oesophageal cancer which is strongly linked to obesity and acid reflux.
Both these conditions are themselves associated and on the increase. One large Norwegian study showed a rise in acid reflux rates from 11% to 17% over a decade from the early 1990s.
Tim Underwood, an oesophageal surgeon and researcher at the University of Southampton, said: “Between 10% and 14% of the population will have reflux at any time and, yes, reflux is getting more common.
“From a surgical point of view, we’re seeing a link between obesity and reflux and there is definitely a link between obesity and oesophageal adenocarcinoma. So you could join the three dots together.
“We know that obesity can change the dynamics at the border between the oesophagus and the stomach that potentially leads to more reflux.”
Patients are often diagnosed late because early symptoms are ignored or not taken seriously.
When heartburn continues over a long period, it can be tempting to keep it at bay with over-the-counter remedies such as Gaviscon and Zantac.
Yet the accepted medical advice is to carry out a thorough investigation of any case of acid reflux that continues for three weeks or more.
Most people who suffer from heartburn are not at risk of oesophageal cancer. But for a few, changes could be occurring to the cells lining the gullet that may mark a first step to the disease.
Another symptom to watch out for is difficulty swallowing food.
“Diagnosing the disease earlier is key to improving the chances of survival,” said Mr Underwood, speaking at a news briefing in London hosted by Cancer Research UK.
“Food getting stuck when you swallow and persistent heartburn are not normal. If this is happening to you, you need to see your GP. The vast majority of people won’t have anything seriously wrong with them, but it’s important to be checked out.
“If left untreated acid reflux - often called heartburn - can damage cells of the oesophagus leading to a condition called Barrett’s oesophagus, which in turn can be a precursor of oesophageal cancer.”
Family doctors as well as patients had to become more aware of the risks, he said, adding: “What I say to GPs when I go out to visit them is that if a middle-aged man who has never seen you before turns up with reflux it needs to be investigated.
“They’ve come to you for the first time with something that we know is linked to potentially serious disease.”
Professor Rebecca Fitzgerald, from the Medical Research Council’s Cancer Cell Unit in Cambridge, said: “One of the real problems is that heartburn and reflux symptoms are seen as a nuisance, but something that’s quite normal.”
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