A simple at-home saliva test may be more accurate at detecting prostate cancer than the current prostate-specific antigen (PSA) blood test, new National Institute for Health and Care Research (NIHR)-funded research suggests.
This new method could better identify the future risk of cancer for some men. The BARCODE 1 study calculated the risk of prostate cancer from DNA extracted from saliva. This is called a polygenic risk score (PRS).
The study was partly funded by the NIHR Royal Marsden Biomedical Research Centre. It was supported by NIHR Research Delivery Network and published in The New England Journal of Medicine.
For men with the highest risk score, the study found this to be a better tool than the current prostate cancer risk test. The current blood test is used to identify men who are at higher risk of prostate cancer due to their age or ethnicity, or men presenting with symptoms. Men with a high PSA result will be sent for further tests to detect cancer.
However, the PSA test falsely indicates prostate cancer in men three out of four times and detects cancers which grow so slowly they are unlikely to ever be life threatening. This means that some men may undergo unnecessary MRI scans, invasive biopsies and treatments.
Researchers trialled their new DNA saliva test which looks for genetic variants linked to prostate cancer.
For the men with the highest genetic risk, the test:
- picked up people with cancer who would have been missed by the PSA test alone
- picked up a higher proportion of the aggressive cancers than the PSA test
- accurately identified men with prostate cancer that was missed by an MRI scan.
The study calculated the PRS of 6,142 European men recruited from their GP surgeries, aged between 55 to 69 when the risk of prostate cancer is increased. The score is based on 130 genetic variations in the DNA code that are linked to prostate cancer. It was developed by studying the DNA of hundreds of thousands of men.
Those at risk inherit many of these variants and are most at risk of developing the disease. Men with the highest 10% of risk scores - 468 in total - were invited to further screening. Following an MRI and prostate biopsy, 40% of these men were diagnosed with prostate cancer. This compares with the PSA test, in which 25% will have prostate cancer.
Previous studies have shown that the PSA blood test picks up many people who have cancers which do not require treatment. The PRS saliva test identified a higher proportion of aggressive cancers – which are fast growing and likely to spread – than the PSA test. The PRS test is more accurate than an MRI scan for men with high genetic risk.
As the PSA test is sometimes inaccurate, the PRS saliva test could be an additional screening tool for men at higher risk of prostate cancer or those presenting with symptoms.
The £42 million TRANSFORM trial funded by NIHR and Prostate Cancer UK will directly compare the saliva test to the PSA blood test and MRI scan. This will assess whether those with a low genetic risk may benefit from an alternative screening tool. Researchers estimate that the spit test could identify up to 12,350 people earlier, saving the NHS around £500 million a year.
Professor Ros Eeles, Professor of Oncogenetics at The Institute of Cancer Research and Consultant in Clinical Oncology and Cancer Genetics at The Royal Marsden NHS Foundation Trust, said: “With this test, it could be possible to turn the tide on prostate cancer. We have shown that a relatively simple, inexpensive spit test to identify men of European heritage at higher risk due to their genetic makeup is an effective tool to catch prostate cancer early.”
- McHugh JK, Bancroft EK, Saunders E, et al. Assessment of a Polygenic Risk Score in Screening for Prostate Cancer. N Engl J Med. 2025 Apr 9; 392 (14): 1406-1417. doi:10.1056/NEJMoa2407934