MRI may replace prostate biopsy

A quarter of men suspected of having prostate cancer could avoid invasive and potentially dangerous biopsies with the help of MRI scans, researchers reported.

Magnetic resonance imaging (MRI) could also reduce the number of men over-diagnosed with the disease by five percent, they detailed in a study published in The Lancet.

The new approach is potentially a game-changer, experts commenting on the study said. In the case of prostate cancer, “over-diagnosed” includes relatively benign cancers that do not cause any harm during a man’s lifetime.

“Prostate cancer has aggressive and harmless forms,” noted lead author Hashim Ahmed, a surgeon at University College London’s faculty of medicine.

Typically, men undergo a prostate biopsy if they experience certain symptoms or show high levels of a protein in their blood, as detected by a prostate specific antigen (PSA) test.

Each year, over a million prostate biopsies are done in Europe alone. The procedure — which can cause bleeding, pain and serious infections — involves using a biopsy needle to draw a tissue sample through a small cut made between the anus and scrotum. The needle goes in “blind”, and can thus bypass a cancerous mass.

“Our current biopsy test can be inaccurate because the tissue samples are taken at random,” Ahmed said. “It can miss aggressive cancers.”

And if the biopsy does find cancer cells, it cannot reliably determine whether they are malignant.

As a result, some men are given a false diagnosis and prescribed treatments with nasty side effects.

Ahmed and his team wanted to find out if an MRI scan could be used as a “triage” test to determine which men with elevated protein counts might safely avoid a biopsy.