A new at-home saliva test for prostate cancer may be better than current testing methods, a new study has suggested.
Experts have developed the new test which analyses genetic variants in a man's DNA.
The simple test, which can be performed at home and does not require a visit to the GP, appeared to perform better than the current method for assessing prostate cancer risk, according to a new study.
The prostate-specific antigen (PSA) test is a blood test which is currently used to check for prostate conditions including prostate cancer or an enlarged prostate.
The new saliva test could be used as an additional screening tool, experts said, as it reduced the number of false positive results and picked up a higher proportion of aggressive cancers than the PSA test.
This means the use of the test could lead to fewer men being sent for unnecessary testing, they added.
Researchers at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust wanted to assess the effectiveness of a new tool they had developed called a polygenic risk score.
This risk score uses spit to assess 130 genetic variants known to be associated with an increased risk of prostate cancer.
It can then determine whether or not a person is at high risk of disease.
The new trial used the tool to assess 6,300 men aged 55 to 69 in the UK.
Some 745 (12%) were deemed to have a high risk score during the study, nicknamed Barcode 1.
These men were invited to have prostate cancer screening including an MRI scan and a biopsy, with some 468 taking up the offer.
Prostate cancer was detected in 187 men and, of these, 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 usually indicate that no further screening is required.
Writing in the New England Journal of Medicine, researchers said cancer "would not have been detected" in 74 of these men using the "diagnostics pathway" currently in use in the UK - which includes a high PSA level and an MRI.
Experts concluded that for the men with the highest genetic risk, the test falsely identified fewer people with prostate cancer than the PSA test.
It also picked up people with cancer who would have been missed by the PSA test alone and it detected a higher proportion of the aggressive cancers than the PSA test.
The test also accurately identified men with prostate cancer that was missed by an MRI scan.
A separate trial has been launched which will directly compare the saliva tests to the PSA test and an MRI scan.
Professor Ros Eeles, from the Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust, said it "could be possible to turn the tide on prostate cancer" with this test.
"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," he said.
"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."
Clinical Research Fellow at The Institute of Cancer Research, London and the Royal Marsden Hospital Dr Jana McHugh described the saliva test as "groundbreaking".
Speaking on RTÉ's Morning Ireland, she said there has been a lot of issues with the current blood test for prostate cancer and it has led to "over-diagnosis".
"We're hoping what this test will do is to help risk stratify people so we can identify those at higher risk and then that will help to concentrate efforts on screening in some of these higher risk people," she said.
"There have been a lot of problems with trying to develop a screening test for prostate cancer.
"There's been a lot of problems with over diagnosis where the PSA, the prostate specific antigen, can be high for other reasons other than prostate cancer. And that then leads you down the road of over diagnosis potentially or causing people worry when there actually isn't a prostate cancer.
"This is groundbreaking work to try and help to guide our efforts as to who needs to be screened and screened in a targeted way," Dr McHugh said.
Researchers have estimated that the spit test could identify up to 12,350 people earlier, saving the NHS in the UK around £500 million a year.
Around 55,000 cases of prostate cancer are diagnosed each year in the UK.
Some 12,000 men in the UK die from the disease each year, according to Cancer Research UK figures.
