Breath test could diagnose pancreatic cancer at an earlier stage

A breath test can detect pancreatic cancer and could mean the disease can be diagnosed at an earlier stage for the first time, say researchers.

The test has produced encouraging results in a clinical study and will now be tested in a larger multicentre trial at Imperial College Healthcare NHS Trust and five other London hospitals from October.

In a proof of principle and validation study, researchers analysed breath samples of 132 patients at St Mary’s Hospital, part of Imperial College Healthcare NHS Trust, and found the test can correctly identify cancer from benign conditions in 81 per cent of patients who had the disease.

Unlike other methods such as endoscopies the test is non-invasive.  The study, published in the British Journal of Surgery, was led by Imperial College London.

Scientists believe the test could be used to diagnose pancreatic cancer at an earlier stage and screen patients who are most at risk of developing the disease.

Professor George Hanna, lead author of the study at Imperial College London, said:

“We’re in a bleak situation where pancreatic cancer is often diagnosed at a late stage where little can be done to cure patients.  There is a need to develop more effective methods to identify this disease at a much earlier stage.  Our breath test could be one of the solutions to tackling this as it can be used as a first line test on patients who may have non-specific symptoms, or have a family history, so we can direct them to have more specialised tests and offer treatments that can save more lives.”

There are more than 9,000 new cases of pancreatic cancer diagnosed in the UK each year.  The disease is caused by the abnormal and uncontrolled growth of the cells in the pancreas.  Just 20 per cent of patients survive the disease after a year, falling to three per cent after five years.  In comparison, long-term survival rates for breast cancer is 90 per cent.  Early detection of the disease could improve survival rates.

Pancreatic cancer doesn’t cause any signs or symptoms in the early stages and as a result it is difficult to diagnose.  It’s only once the disease is at an advanced stage that symptoms become noticeable such as jaundice.

Doctors currently diagnose the disease by carrying out blood and urine tests when patients have signs of jaundice or weight loss.  If pancreatic cancer is suspected further investigations such as a CT scan or a specialised endoscopy are carried out.  This is a procedure where the inside of the body is examined using a probe with a light source and and/or ultrasound scan at its end at one end. This is inserted via the mouth and travels down the gullet. It would not be possible to refer large numbers of patients who present with non-specific symptoms to have specialised investigations due to the financial cost.

The test looks for chemical compounds in exhaled breath that are unique to patients with pancreatic cancer.  The cancers produce a distinctive smell of volatile organic compounds (VOC), chemicals that contain carbon and are found in all living things, which can help doctors to detect the disease at an earlier stage.  Researchers were able to identify and quantify the number of VOCs in breath samples by using a mass spectrometer, an analytical instrument used to identify what chemicals are present in a sample. 

Researchers took breath samples of 132 patients between March-December 2016.  Of these, 57 had cancer and 75 had other benign diseases and pancreatic conditions.  To take the test, patients breathed into a device and the volatile compounds in their exhaled breath were analysed at the Division of Surgery’s breath analysis laboratory at St Mary’s Hospital.

In separate studies, the test was also shown to diagnose gastric, oesophageal and colorectal cancers as they produce different volatile compounds in the breath.

The research was funded by the National Institute for Health Research (NIHR) Imperial College Biomedical Research Centre (BRC), In-vitro London Diagnostic Cooperative, and Imperial Health Charity.