Saliva test to revolutionise detection of prostate cancer

Experts say the test is better at identifying aggressive tumours than one currently used by NHS

A simple saliva test can identify men who are most at risk of prostate cancer, a breakthrough study has found.
Scientists have developed a spit test that can be taken at home and is more accurate than the protein-specific antigen (PSA) blood test currently used by the NHS.
The test, which looks for genetic markers of the cancer in people’s DNA, was better at identifying aggressive tumours and gave fewer false positives than the PSA test, which results in thousands of men undergoing unnecessary and invasive scans and biopsies each year.
It would likely be available through family doctors and is set to form part of a landmark prostate cancer screening trial in the UK that will identify best practice for a national roll-out that will almost inevitably follow, joining routine checks for breast, bowel and cervical cancers.
Ros Eeles, professor of oncogenetics at the The Institute of Cancer Research (ICR), in London, said the breakthrough could overhaul care for prostate cancer, which kills 12,000 Britons every year.
Presenting the findings at the American Society of Clinical Oncology conference in Chicago, she said: “With this test, it could be possible to turn the tide on prostate cancer.
“We have shown that a simple, cheap, spit test to identify men at higher risk due to their genetic makeup is an effective tool to catch the cancer early.
“Building on decades of research into the genetic markers of prostate cancer, our study shows that the theory does work in practice – we can identify men at risk of aggressive cancers who need further tests and spare the men who are at lower risk from unnecessary treatments.”
Researchers at ICR and The Royal Marsden NHS Foundation Trust trialled the test on 6,142 men through their GP surgeries.
The men, who were aged 55 to 69, gave a sample of saliva which was then tested for 130 genetic variations in the DNA code with links to prostate cancer, known as a polygenic risk score.
Some 558 men whose score was in the highest 10 per cent were invited for further tests, with 468 undergoing a biopsy, of whom 40 per cent were diagnosed with prostate cancer.
This compares with 25 per cent of men with high PSA scores, who typically go on to be diagnosed with the disease.
PSA tests have also been found to pick up tumours that are not of clinical concern and only require monitoring, but sometimes lead to unnecessary surgeries and treatment.
The spit test also diagnosed a higher proportion of men with aggressive cancers that spread more quickly. They accounted for 55.1 per cent of the 187 diagnoses, compared with the 35.5 typically picked up by a PSA test.
Around 52,000 men are diagnosed with prostate cancer in the UK every year, making it the most common cancer among men.
While survival rates have tripled in the past 50 years to about 85 per cent after five years, depending on the stage it is diagnosed, projections indicate that the number of cases each year could double by 2040 to more than 100,000.
The spit test will be part of the biggest trial in a generation, known as Transform, to test the effectiveness of diagnosis techniques, such as the saliva test, against the current PSA test over the next three years.
Prof Eeles said these findings, based on men from across Europe, would be widened to include new markers identified for different ethnicities.
She added: “Our next step will be for us to test the genetic markers we have identified that are associated with a risk of prostate cancer in diverse populations, to ensure this test can benefit all men.”
Future research will follow-up men with high polygenic risk scores to monitor if they go on to develop prostate cancer.
Prof Kristian Helin, chief executive of the ICR, said the findings showed that “we must have a programme in place to diagnose the disease early”.
“We know that the current PSA test can cause men to go through unnecessary treatments and, more worryingly, it’s missing men who do have cancer,” he said.
“We urgently need an improved test to screen for the disease. This research is a promising step towards that goal, and it highlights the role that genetic testing can play in saving lives.”
Naser Turabi, director of evidence and implementation at Cancer Research UK, said: “It’s encouraging to see that genetic testing might help to guide a more targeted approach to screening based on someone’s risk of developing prostate cancer.
“More research is now needed to confirm if this tool can save lives from the disease so that it can be rolled out to improve diagnosis.”
One man who benefited from the trial was Dheeresh Turnbull, 71, from Brighton, who was diagnosed with prostate cancer after taking the saliva test despite having no symptoms.
His younger brother then took the test as a result and found out he had an aggressive tumour. 
Mr Turnbull, a former therapist and lecturer, claims the test “saved” their lives. He was referred to the Royal Marsden, and underwent robotic surgery to remove part of his prostate.
“I was completely shocked when I received my diagnosis as I had absolutely no symptoms at all, so I know I would never have been diagnosed at this stage if I hadn’t joined the trial,” he said.
“Because the saliva test revealed that I had a high genetic risk of developing the disease, my younger brother, who would have been too young to join the study directly, signed up and discovered that he also had an aggressive tumour in the prostate. It’s incredible to think that because of this study two lives have now been saved in my family.”