Could at-home saliva test revolutionise prostate cancer screening?
At-home spit tests are better than the standard blood test for identifying men who have a high genetic risk of developing aggressive prostate cancer, early research suggests.
The preliminary findings, presented at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago, raise hopes of a potentially more accurate screening tool for a disease that claims around 12,000 lives a year in the UK.
There is currently no national screening programme for prostate cancer and the standard blood test, which measures levels of a protein called prostate-specific antigen (PSA), is not accurate enough.
The saliva test, where the sample can be collected at home, looks for genetic variants linked to prostate cancer.
For men with a high genetic predisposition to the disease, spit analysis was more accurate than the PSA test as an early assessment tool, the researchers at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust said.
The team said its research could help “turn the tide on prostate cancer” by offering a cheap and easy-to-use spit test to catch the disease early and save thousands of lives.
It could also spare many others who are at lower risk from unnecessary and invasive treatments, the researchers added.
How was the study carried out?
The BARCODE 1 study recruited 6,142 European men aged 55-69 from their GP surgeries.
The men were deemed to be at an age where the risk of prostate cancer is increased.
The researchers calculated the polygenic risk score – which is based on 130 genetic variations in the DNA code linked to prostate cancer – of all those taking part.
Those with the highest risk scores – 558 men who carried many of these variants – were invited for further screening.
The team found the saliva test gave fewer false positive results and picked up a higher proportion of aggressive cancers than the PSA blood test.
Following an MRI scan and biopsy, 40% of men with high scores from the saliva test were diagnosed with prostate cancer.
In case of PSA tests, only 25% of men with a high PSA level will actually have prostate cancer, the researchers said. This is because the PSA test is not accurate enough and can falsely indicate cancer in men three out of four times.
It can also miss cancers that require urgent treatment and detect ones that are unlikely to ever be life-threatening.
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Professor Kristian Helin, chief executive of ICR said: “Cancers that are picked up early are much more likely to be curable, and with prostate cancer cases set to double by 2040, 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.
“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.”
Where to get help
If you are concerned you may be displaying symptoms consistent with prostate cancer you can access help from the following organisations:
Prostate Cancer UK offers a range of support resources on its official website, including physical and mental wellbeing and financial advice;
The NHS advises anyone with suspected symptoms to visit their GP at the earliest opportunity. A general overview of the disease is available online, with information available on areas from diagnosis to treatment options;
MacMillan Cancer Support operates a free to use daily support line (08088 08000) between 8am to 8pm as well as an online chat service