Behind the headlines: Could this spit test diagnose prostate cancer?

This week, researchers from The Institute of Cancer Research, London, (ICR) made headlines by announcing that their at-home spit test could spot which men are most at risk of prostate cancer. 

The spit test is not commercially available, but the researchers have been studying it in a clinical trial called BARCODE 1 and have now published the results. 

What does the test do?

The test doesn’t look for signs of prostate cancer inside the body. 

Instead, it looks at a man’s DNA for small changes that increase his risk of prostate cancer. 

That makes it different to the PSA blood test, which measures the level of a molecule made by the prostate itself. 

A high PSA level can be a sign of a prostate problem, though not necessarily prostate cancer.  

What did the BARCODE 1 study look at?

BARCODE 1, the clinical trial behind this spit test, collected spit samples from more than 6,000 white men aged 55 to 69. 

These men’s genetics were analysed from their spit, with researchers looking at 130 genetic differences that have been linked to prostate cancer.  

From these results, the researchers were able to give each man a personalised prostate cancer risk score. 

The 10 per cent of men with the highest risk scores were invited for an MRI scan and a prostate biopsy. Of these men, 40 per cent were diagnosed with prostate cancer.

How did Prostate Cancer UK funding lead to this research?

We’ve been funding the lead researcher, Professor Ros Eeles, and her research into the genetics of prostate cancer for many years. 

In fact, we awarded one of our very first research grants to her in 1995, to buy a machine that can detect and make millions of copies of DNA fragments – making it possible for her to study the genetics of prostate cancer.

Then, in 1998, we funded a project she led to investigate men’s genetic predisposition to prostate cancer.

In total we’ve funded 13 grants to Professor Eeles since that first one in 1995. Many of those projects contributed to the discovery of the 130 genetic differences, tested in BARCODE 1, that are linked to a man’s risk of prostate cancer.

Is there other research looking at prostate cancer genetics?

PROFILE – another study funded by us and run by Professor Eeles – is looking at genetic risk factors in Black men and men with a family history of prostate cancer.  

BARCODE 1, PROFILE and other studies like them should help us better understand which men are most at risk of the disease so they can be monitored most closely and, hopefully, diagnosed earlier. 

Their findings will also feed into TRANSFORM, our clinical trial that’s getting the evidence we need for a screening programme for prostate cancer. 

Why are they developing another test for prostate cancer?

Currently, prostate cancer is the most common cancer without a screening programme. 

This means too many men in the UK are being diagnosed with advanced, incurable prostate cancer.  

An effective, cost-efficient way to screen men would make a huge impact, giving thousands of men a year the chance of an earlier diagnosis and a longer, healthier life. 

By picking up which men are at greatest risk of prostate cancer, the ICR test could help doctors find more cases of the disease earlier, when it’s easiest to cure. 

Dr Matthew Hobbs, our Director of Research, said: “We’ve been supporting Professor Eeles's research with regular funding for 30 years, so we’re delighted to see the progress she and her team have made.    

“BARCODE 1 is the latest step in that journey and shows that the discoveries she’s driven are now at a stage where they can be used to measure a man’s genetic risk of prostate cancer and may enable us to diagnose aggressive prostate cancers sooner and more accurately.” 

A further step towards prostate cancer screening

While this genetic test is a step in the right direction, our landmark £42m TRANSFORM trial is designed to provide the final pieces of the jigsaw that will lead to a screening programme for prostate cancer.  

TRANSFORM researchers will study genetic testing alongside other techniques like MRI scans to find the best way to screen men for prostate cancer. 

Dr Hobbs added: “BARCODE 1 is a real story of success, but it’s not the end of the story. 

"We're committed to pushing for irrefutable evidence for prostate cancer screening and our £42m TRANSFORM trial is the way that will happen. Professor Eeles is one of the TRANSFORM co-leads, and will test this genetic risk approach to make sure it works at scale, and for men of all ethnicities. 

“We’re proud to have laid the foundations for this research through our previous funding, and to have committed the funding and expertise needed to try and get this into the NHS so it can benefit men.    

“Until then, the PSA blood test can reduce the number of men who are diagnosed late and is available for free on the NHS.” 

Although this research is exciting, the best test for prostate cancer is still the PSA blood test, which men can get for free from their GP.  

Any man who is concerned about prostate cancer can use our online Risk Checker to find out his own risk and what he can do about it. 

Check my risk