British researchers have found that a new at-home spit test for prostate cancer is more accurate than current screening methods, and so effective it could “turn the tide” on the disease and help identify at-risk men without the need for a GP appointment.
They estimate it could find 12 350 tumours at an earlier stage, when the disease is easier to treat, saving the NHS £500m a year.
The simple saliva test analyses genetic variants in a man’s DNA, and appears to perform better than the current method for assessing prostate cancer risk – the prostate-specific antigen (PSA) blood test, which checks for prostate conditions, including prostate cancer or an enlarged prostate.
Using the test as an additional screening tool would reduce the number of false positive results and detect a higher proportion of aggressive cancers than the PSA test, and result in fewer men being sent for unnecessary testing, said the researchers at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust.
They tested the effectiveness of a new tool they had developed called a polygenic risk score, which uses spit to assess 130 genetic variants known to be associated with an increased risk of prostate cancer and which can then determine whether or not a person is at high risk of the disease.
Test saved lives of siblings
Sky News reports that taking part in the trial saved the lives of two brothers, with one saying traditional methods to assess prostate cancer deemed he had a low risk of disease, but the new spit test helped the 71-year-old discover he actually had a life-threatening tumour in his prostate.
After finding out the news, his brother also took part in the study and discovered he too had an aggressive prostate tumour.
The two were among 6 300 men aged 55 to 69 in Britain who were assessed by the tool as part of the study.
Of those, 745 (12%) were deemed to have a high risk score and were invited to have prostate cancer screening, including an MRI scan and a biopsy.
Prostate cancer was detected in 187 of the 468 who took up the offer, and of those, 103 had cancer that was deemed to be “higher risk”, so treatment was offered.
Of the 187 men, 118 had a PSA level below 3.0ug/L – which is considered “normal” and would typically indicate no further screening is required.
Test could ‘turn the tide’
Writing in the New England Journal of Medicine, the researchers said cancer would not have been detected in 74 of the men using the “diagnostics pathway” currently in use in the UK, which includes a high PSA level and an MRI.
They concluded that for the men with the highest genetic risk, the test falsely identified fewer people with prostate cancer than the PSA test, and picked up people with cancer who would have been missed by the PSA test alone.
It detected a higher proportion of aggressive cancers than the PSA test and also accurately identified men with prostate cancer who were missed by an MRI scan.
Professor Ros Eeles, from the Institute of Cancer Research, and 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 make-up is an effective tool to catch prostate cancer early.”
Some 55 000 cases of prostate cancer are diagnosed each year in the UK, with around 12 000 men in the UK dying from the disease annually, according to Cancer Research UK.
Study details
Assessment of a Polygenic Risk Score in Screening for Prostate Cancer
Jana McHugh, Elizabeth Bancroft, Edward Saunders et al.
Published in the New England Journal of Medicine on 9 April 2025
Abstract
Background
The incidence of prostate cancer is increasing. Screening with an assay of prostate-specific antigen (PSA) has a high rate for false positive results. Genome-wide association studies have identified common germline variants in persons with prostate cancer, which can be used to calculate a polygenic risk score associated with risk of prostate cancer.
Methods
We recruited persons 55 to 69 years of age from primary care centres in the United Kingdom. Using germline DNA extracted from saliva, we derived polygenic risk scores from 130 variants known to be associated with an increased risk of prostate cancer. Participants with a polygenic risk score in the 90th percentile or higher were invited to undergo prostate cancer screening with multiparametric magnetic resonance imaging (MRI) and transperineal biopsy, irrespective of PSA level.
Results
Among 40,292 people invited to participate, 8953 (22.2%) expressed interest in participating and 6393 had their polygenic risk score calculated; 745 (11.7%) had a polygenic risk score in the 90th percentile or higher and were invited to undergo screening. Of these 745 participants, 468 (62.8%) underwent MRI and prostate biopsy; prostate cancer was detected in 187 participants (40.0%). The median age at diagnosis was 64 years (range, 57 to 73). Of the 187 participants with cancer, 103 (55.1%) had prostate cancer classified as intermediate or higher risk according to the 2024 National Comprehensive Cancer Network (NCCN) criteria, so treatment was indicated; cancer would not have been detected in 74 (71.8%) of these participants according to the prostate cancer diagnostic pathway currently used in the United Kingdom (high PSA level and positive MRI results). In addition, 40 of the participants with cancer (21.4%) had disease classified as unfavourable intermediate risk or as high or very high risk according to NCCN criteria.
Conclusions
In a prostate cancer screening program involving participants in the top decile of risk as determined by a polygenic risk score, the percentage found to have clinically significant disease was higher than the percentage that would have been identified with the use of PSA or MRI.
NEJM article – Assessment of a Polygenic Risk Score in Screening for Prostate Cancer (Open access)
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