A new saliva-based test may dramatically improve early detection of prostate cancer, offering a more precise alternative to the standard PSA blood test. Unlike the traditional method, the test can be performed at home, providing a simpler and potentially more effective approach for identifying men at high risk.
DNA-Based Risk Assessment Outperforms PSA
The BARCODE 1 study, recently published in the New England Journal of Medicine, investigated the use of DNA extracted from saliva to calculate a polygenic risk score (PRS) for prostate cancer. This score evaluates a man’s inherited genetic risk based on 130 DNA variants linked to the disease.
For men with the highest genetic risk, the saliva test proved more effective than PSA testing. It reduced false positives, identified cancers that PSA would miss, and detected a greater proportion of aggressive tumors. By contrast, the PSA test often signals cancer when none exists and can prompt unnecessary procedures such as MRIs, biopsies, or treatments for slow-growing tumors unlikely to cause harm.
Trial Design and Key Findings
The study enrolled 6,142 European men aged 55–69, a demographic at elevated risk for prostate cancer. Men in the top 10% of risk scores underwent further screening, including MRI and biopsy. Of 468 high-risk men, 187 (40%) were diagnosed with prostate cancer, compared with just 25% detection among those with elevated PSA alone. Notably, 118 of these men had PSA levels considered “normal,” demonstrating the saliva test’s ability to identify hidden cancers.
Importantly, the saliva test detected a higher proportion of aggressive cancers—55.1% compared to 35.5% via PSA—and identified tumors missed by MRI in 125 men (66.8%). These results suggest that the test could enhance early detection for men most at risk, while sparing others from unnecessary intervention.
Expanding the Research
Following the initial study, researchers developed PRODICT®, an updated version of the test that includes additional genetic variants and can be used for men of Asian and African ancestry. A new trial, TRANSFORM, funded partly by Prostate Cancer UK, will directly compare the saliva test to PSA and MRI to determine the most cost-effective screening method. Preliminary estimates suggest the test could identify over 12,000 men earlier, potentially saving the NHS around £500 million annually.
Expert Perspectives
Professor Ros Eeles of The Institute of Cancer Research highlighted the significance of the findings: “This relatively simple, inexpensive spit test can catch aggressive prostate cancers early while sparing men at lower risk from unnecessary treatments. Our updated test aims to reach diverse populations and younger men with genetic predisposition.”
Professor Kristian Helin added, “With prostate cancer cases expected to double by 2040, early detection is critical. Genetic testing offers a promising path to identifying high-risk individuals before the disease progresses.”
Real-Life Impact
Dheeresh Turnbull, 71, from Brighton, was diagnosed with prostate cancer through the BARCODE 1 trial despite a low PSA score. The saliva test also helped detect cancer in his younger brother, illustrating the life-saving potential of genetic screening.
“This study saved two lives in my family,” Turnbull said. “I would never have been diagnosed at this stage without it.”
Conclusion
As research continues, the saliva-based polygenic risk score test could transform prostate cancer screening, offering targeted, accurate, and less invasive detection. The combination of genetics and traditional screening may represent the next frontier in reducing unnecessary procedures and improving outcomes for men worldwide.
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