Doctors may one day be able to detect one of the deadliest and hardest to spot cancers by looking at your faeces.
Nearly 30 microorganisms in human excrement have been linked to the disease, regardless of whether it is at an early or advanced stage.
Scientists who made the discovery hope it will lead to new screening tests for the disease, which is often detected too late to cure.
Currently only a quarter of people diagnosed with pancreatic cancer live more than year, and only 5 per cent survive a decade.
Pancreatic cancer is currently diagnosed using blood tests, scans or surgery, all of which can be expensive. Symptoms include back pain, indigestion, and a change in bowel habits.
But a team of European researchers have identified 27 species of microorganisms, mostly bacteria, in the gut that could be spotted by a simple stool sample.
Scientists have found a collection of microbes that if found in a stool sample could indicate a person has pancreatic cancer. Cancer of the pancreas (the organ highlighted in red) has only vague symptoms and is found too late in the vast majority of cases
It is the latest study to highlight the importance of the microbiome, a natural collection of fungi, bacteria and viruses and cancer with previous research linking this community of organisms to stomach and prostate cancer risk.
Pancreatic cancer is extremely deadly in part because of how difficult it is to detect and treat.
About 9,000 Britons die from pancreatic cancer every year. The figure stands at around 50,000 in the US.
The best chance of curing the cancer is surgery to remove the cancerous tissue, but only 10 per cent of people have this option as it is normally only detected when the tumour has already started to spread to other parts of the body.
The study, part-funded by Worldwide Cancer Research, involved over 100 people who submitted both stool and spit samples to scientists.
Of these, 57 had pancreatic cancer, with 25 at an early stage of the disease and 32 advanced.
Another 50 without cancer acted as a control group.
The samples were then analysed by the Spanish National Cancer Research Centre (CNIO) and the European Molecular Biology Laboratory, who published their findings in the journal Gut.
Scientists highlighted how the bacteria Methanobrevibacter smithii, Fusobacterium nucleatum, Alloscardovia omnicolens, Veillonella atypica and Bacteroides finegoldii were more abundant in stool samples from cancer patients.
On the other hand, the microorganisms Faecalibacterium prausnitzii, Bacteroides coprocola, Bifidobacterium bifidum or Romboutsia timonensis were depleted in these patients compared to the controls.
They found that this ‘microbial profile’ was consistent with patients with pancreatic cancer regardless of what stage it was at, raising hopes it could one day that a stool sample test could be used as an early detection method.
The scientists added it was ‘feasible’ for a screening programme to be developed using stool samples that may help pick up pancreatic cancer.
The pancreas is an leaf-shaped organ, about 15cm long located under the liver, close to the stomach and the bowel.
It makes hormones that regulate the level of sugar in the blood and also makes digestive juices.
Dr Nuria Malats, an expert in pancreatic cancer from CNIO who co-authored the study, said although the study was observational and couldn’t say if the microbiome changes were a result of the cancer the results were promising.
‘Nevertheless, there are strong indications that the identified faecal microbiome shifts are not merely a consequence of impaired pancreatic function or systemic effects thereof, although indirect effects cannot be ruled out,’ she said.
Pancreatic cancer symptoms include back pain, indigestion, unexplained weight loss, changes in bowel habits, but these are also signs of far less serious health conditions.
Only about one in five people with pancreatic cancer get a diagnosis at the early stage of the disease when they have the best outcome for survival.
Dr Helen Rippon, chief executive of Worldwide Cancer Research, said the study may help develop a new tool in the fight against this type of cancer.
‘What’s amazing about this discovery is that the microbiome of stool samples from patients could be used to help diagnose pancreatic cancer early,’ she said.
‘Early detection and diagnosis are just as important an approach to starting new cancer cures as developing treatments.
‘This research provides hope that an effective, non-invasive way to diagnose pancreatic cancer early is on the horizon.’
Reacting to the study, Dr Chris MacDonald, head of research at charity Pancreatic Cancer UK said: ‘New, more accurate biomarkers for the detection of pancreatic cancer are urgently needed and it’s vital that we leave no stone unturned.’
‘We desperately need an early detection tool capable of helping GPs diagnose thousands more people at early symptomatic stage in time for lifesaving treatment.’
He added that further research needed to be done on if a potential microbiome marker like a bacteria species in a stool sample, could be found in people with vague symptoms of pancreatic cancer, not just in those with a confirmed disease.