The test is highly accurate
Scientists have developed a test that can diagnose oesophageal, or gullet, cancer with unprecedented accuracy.
The University College London team hope it could dramatically improve survival from the disease - which is boosted if the cancer is spotted early.
The test, which measures levels of a protein taken from the oesophagus, may be able to spot early signs of cancer even when symptoms are absent.
Details of the research are published in the British Journal of Cancer.
The new test works by detecting levels of a protein called Mcm5 in fluid samples taken from the oesophagus.
Oesophageal cancer symptoms
Difficulty swallowing, especially with solid food
Pain in the form of pressure, or a burning sensation, as food goes down the oesophagus
Pain or discomfort in the throat or back, behind the breastbone or between the shoulder blades
Regurgitation or vomiting
Hoarseness or chronic cough
Mcm5 is one of a family of proteins called minichromosome maintenance (MCM) proteins, which are a sign of the uncontrolled cell growth that is the hallmark of cancer.
Oesophageal cancer is often difficult to diagnose in its early stages, partly because of its lack of distinct symptoms.
The team analysed samples from 40 patients at Addenbrooke's Hospital in Cambridge to assess whether the Mcm5 test could accurately detect cancer.
Approximately half of the patients in the study had oesophageal cancer and half did not.
The test was able to identify cases of disease with 85% accuracy.
Professor Gareth Williams, who heads the research group, said: "As oesophageal cancer is particularly difficult to diagnose early, doctors and patients would benefit greatly from a simple test to detect the condition.
"Research shows that early diagnosis is the single most important factor for improving survival prospects for patients with oesophageal cancer."
Five-year survival from oesophageal cancer in the UK is currently around 8%.
But where the disease is diagnosed early, surgery and chemotherapy can yield survival rates in excess of 80%.
Dr Stephen Middleton, who led the clinical trial at Addenbrooke's Hospital, said: "Current tests rely on a pathologist or technician analysing cell changes through a microscope.
"But as the new test is chemical in nature it could be readily automated, making it suitable for screening large numbers of people for precancerous or cancerous changes in oesophageal cells.
"The test would be much less invasive than the endoscopic tests currently used to regularly check the oesophageal lining of patients who have a high risk of developing cancer. This would make it safer and more convenient for patients.
"If large-scale trials prove the test's effectiveness, it could enter use within five years."
Mcm5 plays a key role in cell division. In normal cells its levels are tightly regulated so that cells only divide when they are required to do so.
Cancer develops when these controls break down, leading to very high levels of Mcm5 and uncontrolled cell division.
Professor Williams said: "Testing for high levels of Mcm5 could enable doctors to pick up cancer at an early stage, as it reflects a faulty cellular process that begins long before the tumour reaches an easily detectable size."
The UCL team now plans to investigate the test's clinical viability through a large-scale trial.
There are over 7,000 cases of oesophageal cancer in the UK each year, making it the ninth most common cancer.
Incidence of the disease has risen by 27% in the last 15 years.