New test gives hope for early diagnosis of oesophageal cancer
A new screening test for oesophageal (food pipe) cancer could dramatically improve survival from the disease, according to research published in the British Journal of Cancer this week.
Cancer Research UK funded scientists at University College London's Wolfson Institute for Biomedical Research used a protein in fluid taken from a person's oesophagus to diagnose cancer with unprecedented accuracy.
Oesophageal cancer is often difficult to diagnose in its early stages, partly because of its lack of distinct symptoms. The potential new test would be simple and inexpensive and holds promise for improving detection of the cancer. The 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 per cent in the last 15 years.
The new test works by detecting levels of a protein called Mcm5 in fluid samples taken from the oesophagus using a narrow tube.
Mcm5 is one of a family of proteins called minichromosome maintenance (MCM) proteins, which are already known to be good markers of the uncontrolled cell growth that is the hallmark of cancer.
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, distinguishing between patients with and without oesophageal cancer with 85 per cent accuracy.
Dr Kai Stoeber, lead researcher on the project, says: "Our team has been studying MCM proteins for a number of years to find out how they might prove useful in diagnosing cancer.
Cancer Research UK Senior Clinical Research Fellow Professor Gareth Williams, who heads the research group, adds: "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 eight per cent. But where the disease is diagnosed early, surgery and chemotherapy can yield survival rates in excess of 80 per cent.
Dr Stephen Middleton, who led the clinical trial at Addenbrooke's Hospital, says: "Our pilot study has shown that the Mcm5 test has many advantages over the methods doctors currently use to detect oesophageal cancer.
"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 adds: "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."
Cancer Research UK holds the patent on the Mcm5 test, and the research team are currently seeking commercial partners to develop it further.
Cancer Research UK's Director of Policy and Communications Professor Robert Souhami says: "Low survival rates for oesophageal cancer are to a great extent a result of late diagnosis. Until we have a reliable, accurate and practical test to diagnose the disease at an early stage it will be difficult to improve survival prospects.
"Professor Williams and his team are making a great contribution towards this goal using the Mcm5 protein. A large-scale trial will tell us if using the test is feasible and can save lives."
Notes to Editor
Cancer Research UK is Europe's largest cancer charity and owns the British Journal of Cancer.
Visit our CancerHelp UK website for clear, easy to understand information about oesophageal cancer and its diagnosis and treatment. CancerHelp UK also carries a searchable database of clinical trials open for recruitment in the UK.
Professor William's team has previously shown that detecting high levels of Mcm5 in urine is a very good indicator of early stage bladder and prostate cancers. Cancer Research UK is currently funding a large three-year clinical trial involving 3,000 patients to develop that test further.
Although the team collected oesophageal fluid samples during the standard endoscopy procedures doctors use to examine patients with symptoms of oesophageal cancer, fluid collection for the Mcm5 test could be simplified and conducted without the need for hospitalisation.
Population screening for oesophageal cancer already takes place in countries such as Japan and China, where incidence of one type of the disease - known as squamous cell carcinoma - is very high. However, the techniques used are complex and require the expertise of a number of trained specialists.
The UK has the third highest rate of oesophageal cancer incidence in the EU, after France and Hungary.
The Mcm5 test can detect both types of oesophageal cancer - squamous cell carcinoma and adenocarcinoma - meaning the test would be useful across the world. Different countries have widely differing rates of each oesophageal cancer type.
Squamous cell carcinoma
Squamous cell carcinomas are found mainly in the upper third and middle of the oesophagus, and develop in the squamous cells that make up the lining of the oesophagus. Squamous cell carcinoma is the most common type of oesophageal cancer in Asia.
Adenocarcinomas start in the cells in the lining of the oesophagus that make mucous. This type of cancer is found mainly in the lower third of the oesophagus. Adenocarcinoma is the type of cancer that is most associated with acid reflux and Barrett's oesophagus, and is more common in Western countries.
Oesophageal cancer has a number of symptoms, many of which can be caused by unrelated conditions. Nevertheless, it is important that you report them to your doctor:
- Difficulty swallowing, especially with solid food
- Pain in the form of pressure, or a burning sensation, as food goes down the oesophagus
- Weight loss
- Pain or discomfort in the throat or back, behind the breastbone or between the shoulder blades
- Acid indigestion
- Regurgitation or vomiting
- Hoarseness or chronic cough