Scientists develop cheap and fast spit test for prostate cancer
Scientists have developed a spit test that could turn the tide on prostate cancer worldwide by detecting the disease earlier, detecting where men are at high risk and sparing others unnecessary treatment.
The number of men diagnosed with prostate cancer worldwide is expected to double to 2.9 million per year by 2040, with annual deaths expected to increase by 85%. It is already the most common form of cancer in men in more than 100 countries.
Early diagnosis is crucial, but experts say current standard PSA blood tests can miss men who have cancer and also cause others to undergo unnecessary treatment or pointless further checks and scans.
Now researchers from the Institute of Cancer Research, London (ICR) and the Royal Marsden NHS Foundation Trust appear to have found a better alternative.
Research shows that their new saliva test, which collects a DNA sample within seconds, is more accurate than the current standard blood test. The findings will be presented this weekend at the world’s largest cancer conference.
“With this test it could be possible to turn the tide on prostate cancer,” says Ros Eeles, professor of oncogenetics at the ICR. “We have shown that a simple, inexpensive spit test to identify men who are at higher risk due to their genetic makeup is an effective tool for detecting the cancer early.”
Speaking at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago, Eeles said the breakthrough came after decades of research into the genetic markers of the disease.
“Our research shows that theory works in practice: we can identify men at risk for aggressive cancers who need further testing, and spare those at lower risk from unnecessary treatments.”
Scientists and doctors developed the spit test after studying the DNA of hundreds of thousands of men. It works by looking for genetic signals in the saliva that are linked to prostate cancer.
In the Barcode 1 trial, researchers recruited more than 6,000 European men to try out the spit test. They were all recruited through their GP practices and were aged between 55 and 69 – an age when the risk of prostate cancer is higher.
After the saliva was collected, the test calculated each of the men’s polygenic risk score (PRS). The score is based on 130 genetic variations in the DNA code associated with prostate cancer.
Among those with the highest genetic risk, the test produced fewer false positives than the PSA test, identified people with cancers that would have been missed by the PSA test alone, and detected a greater proportion of aggressive cancers than the PSA test. the PSA test. the ICR said.
The test also accurately identified men with prostate cancer who had been missed by an MRI scan.
Dheeresh Turnbull, 71, from Brighton, was one of the first men in the world to try the spit test and discovered he had prostate cancer when he got the result.
He said: “I was completely shocked when I got my diagnosis as I had absolutely no symptoms so I know I would never have been diagnosed at this stage if I hadn’t taken part in the study.”
Turnbull underwent robotic surgery to remove part of his prostate and is doing well.
He said: “Because the saliva test showed that I had a high genetic risk of developing the disease, my younger brother, who would have been too young to participate directly in the study, enrolled and discovered that he also had a had an aggressive tumor in the prostate. It is incredible to think that two lives in my family have now been saved thanks to this research.”
Eeles, a consultant in clinical oncology and cancer genetics at the Royal Marsden NHS Foundation Trust, warned that further research would be needed before the test could be rolled out on a large scale.
“Our next step will be to test the genetic markers we have identified that are associated with prostate cancer risk in diverse populations, to ensure this test can benefit all men.”
Due to an aging population and increasing life expectancy, the number of older men worldwide who are living longer is increasing. Because the main risk factors for prostate cancer – such as being 50 years or older and having a family history of the disease – are unavoidable, experts believe it will be impossible to prevent the increase in cases simply through lifestyle changes or health interventions. public health.
However, better testing and earlier diagnosis can help reduce the burden and save lives.
“Cancers that are caught early have a much greater chance of being cured,” says Prof. Kristian Helin, the CEO of the ICR. “And with the number of prostate cancer cases set to double by 2040, we need a program to diagnose the disease early.
“We know that the current PSA test can lead to men having to undergo unnecessary treatments, and more worryingly, it is missing men who do have cancer. We urgently need an improved test to detect the disease. This research is a promising step toward that goal and highlights the role genetic testing can play in saving lives.”