Behind the headlines: Could a new blood test for prostate cancer really end the need for biopsy?

If prostate cancer is caught early enough, it can be cured. The problem is, the tests we currently have to help diagnose prostate cancer can be unreliable, meaning they miss some cancers, or result in some men having unnecessary and invasive biopsies. We urgently need better tests.

Research from Queen Mary University London in the news today has presented a new kind of test which could be used alongside current tests such as the PSA test (a blood test which measures the level of prostate-specific antigen (PSA) ­- a protein made only by the prostate gland) and mpMRI scans, to result in a prostate cancer diagnosis that is 90 per cent accurate, when compared to biopsy results. The use of the new test alongside a PSA test and mpMRI scan was also estimated to be able to reduce the number of biopsies used to help diagnose men.

These results have prompted claims in the news that the test could become “available in the NHS within three years”.

However, although a promising step forward towards improving diagnosis, we believe these results should be taken with caution. Only 100 men were involved in this study, meaning that it needs to be tested in a much larger group of men in a properly controlled randomised clinical trial, before clinicians can use it to confidently rule people out of a biopsy. 

How it works: using cells straight from the cancer to help detect aggressive disease

The test detects circulating tumour cells, or CTCs, that have left prostate cancer tumours and entered the blood stream. The potential of using CTCs to help diagnose prostate cancer has been investigated before, but there are difficulties with the number of CTCs that can be detected by current methods.

In this study, the researchers used a new technique to collect CTCs, called Parsortix, which used additional features about the CTCs, like their size and shape, to improve how many could be collected. The researchers also found that extracting genetic information from the CTCs could improve how accurately they could be used to diagnose prostate cancer.

However, there are still some limitations to using CTCs in diagnostic tests. For example, the researchers weren’t able to detect CTCs in all the men in their study, meaning this kind of test may not be suitable for use in all men.

Focusing on improving access to mpMRI to reduce unnecessary biopsies

Although early results for this test look promising, focusing on improving prostate cancer diagnosis is still top priority. We’re investing in research into better diagnostic tests and ways to improve the PSA test, to help bring us closer to a national screening programme for prostate cancer.

For now though, the best way to improve the accuracy of diagnosis and reduce the number of unnecessary biopsies is to champion the introduction of mpMRI. Following a PSA test, a high-quality mpMRI scan can be used to identify potential cancerous lesions, ruling some men out of an unnecessary biopsy and helping to guide biopsy needles for a more accurate diagnosis. This is currently the gold standard for diagnosing prostate cancer but is not yet available to all men in the UK.

We are focusing on ensuring all men have access to this important step in the diagnosis pathway by 2020, as well as funding new research into better tests to improve diagnosis.