A new spit test for prostate cancer which can be done at home may be better than current testing methods, a study suggests.
Experts have developed a simple saliva test which analyses genetic variants in a man’s DNA, which appears to perform better than the current method for assessing prostate cancer risk.
Currently, the prostate-specific antigen (PSA) blood test is used to check for prostate conditions, including prostate cancer or an enlarged prostate.
Routine testing is not currently available on the NHS, but patients may be offered a PSA test if a GP suspects they have prostate cancer. Men over 50 can ask their GP for a PSA test even if they do not have symptoms.
But experts have said the new saliva test could be used as an additional screening tool, as it reduced the number of false positive results and detected a higher proportion of aggressive cancers than the PSA test.
It could lead to fewer men being sent for unnecessary testing, according to 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, which can then determine whether or not a person is at high risk of the disease.
The new spit test for prostate cancer. Pic: PA
Test saved lives of two brothers
Taking part in the trial saved the lives of two brothers.
Dheeresh Turnbull said 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 Joel Turnbull also took part in the study and discovered he had an aggressive prostate tumour.
“It’s incredible to think that because of this study two lives have now been saved in my family,” Dheeresh said.
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How the tool was assessed
The brothers were among 6,300 men aged 55 to 69 in the UK 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 on prostate cancer’
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, London, 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.
It comes after Health Secretary Wes Streeting suggested he would support a national prostate cancer screening programme for men at higher risk of disease if it is backed by the evidence. The UK’s National Screening Committee is currently assessing whether or not such a programme should be rolled out.
