Some prostate cancers could be diagnosed from MRI alone

New research from UCL and UCLH suggests that prostate cancer in some men can be identified from an MRI scan with a very high degree of confidence, potentially reducing the need for a biopsy.

Four experienced radiologists, working both individually and as a group, identified a subset of patients in whom they were ‘99 per cent sure’ there was tumour. Every one of these patients (69/69, 100 per cent) turned out to have clinically significant cancer on biopsy. This has raised the possibility that some men could be offered treatment without first undergoing a biopsy.

The research, published in the European Journal of Radiology, looked at 880 men who attended UCLH’s one-stop clinic for suspected prostate cancer over a one-year period. Of these, 251 had scans showing moderate to high suspicion of cancer. The radiologists then independently reviewed these scans, rating how confident they were that each showed significant cancer, without knowing the biopsy results.

In 79 of the 251 cases, the radiologists judged the scan to be ‘99 per cent sure’ for significant cancer. Of the 69 of these men who went on to have a biopsy, every single one (100%) was confirmed to have clinically significant prostate cancer, and almost three-quarters had intermediate or higher-grade disease. A further 45 patients were rated ‘90% sure’ by the group, and 98 per cent of those biopsied were also confirmed to have significant cancer.

Taken together, these two highest-confidence groups accounted for around 14 per cent of all men attending the clinic. Among them, only one man in 121 turned out not to have significant cancer on biopsy, a false-positive rate lower than that already accepted for treating some kidney and testicular tumours without biopsy.

Biopsy remains the standard way of confirming a prostate cancer diagnosis, but it is an invasive procedure that carries a small risk of infection, urinary problems and other side effects, and can occasionally miss a tumour that is present. Reducing reliance on biopsy (for a carefully selected group of patients) could mean faster access to treatment and less discomfort and anxiety for patients, without compromising safety.

The findings also suggest that some men may not need a PSMA PET scan in addition to MRI, an additional test that has been used to build confidence before treatment without biopsy, although the authors stress this needs further study.

UCLH consultant radiologist Alex Kirkham said: “For a number of cancers, we already treat patients on the strength of imaging alone, without putting them through an invasive biopsy first. This study suggests prostate cancer could, in some cases, join that list. If we can confirm these findings in larger, multicentre studies, it could mean some men reach treatment faster and avoid a procedure that, while generally safe, is not without risk or discomfort.

He added: “What surprised us was how confidently we could call some of these scans, even when the tumours were small or PSA levels looked unremarkable. It tells us that a proportion of prostate cancers have a genuinely distinctive appearance on MRI, one that experienced readers can recognise with a very high degree of certainty.”

Prostate cancer is now the most common cancer in the UK, with more than 64,000 men diagnosed each year, up from just under 52,000 in 2021. This is a 24 per cent increase that has pushed prostate cancer ahead of breast cancer as the UK’s most commonly diagnosed cancer.

Professor Mark Emberton (UCL Division of Surgery and Interventional Science and UCLH consultant neurologist) said: “Globally, around 4-5 million prostate biopsies are carried out each year, yet in the NHS, the wait for a biopsy and its results is the most commonly breached target across all cancer pathways. This matters because prostate cancer incidence is only set to rise: a Lancet Commission paper projects that global cases will double by 2040, driven largely by ageing populations. Together, these pressures make faster, more reliable ways of diagnosing prostate cancer an urgent priority.”

The team’s next steps are to define more precisely, and more objectively, the imaging features that identify these near-certain cases, including exploring whether they can be captured using radiomics and machine learning, and to test whether the approach holds up when used by radiologists with different levels of experience in other hospitals.

Source: University College London.

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