Specialist MRI Shows Promise in Detecting Advancing Prostate Cancer

20 December 2010 - An advanced type of magnetic resonance imaging (MRI) could be used instead of an invasive biopsy to decide whether prostate cancer patients with low-risk cancer need treatment.

Men diagnosed with early stage prostate cancer can choose to be managed by Active Surveillance – regular monitoring by biopsy and testing levels of prostate specific antigen (PSA) in the blood – in the hope of delaying or even avoiding treatment.

However, biopsies are invasive and carry side-effects while PSA testing can be inaccurate, so scientists are looking for other ways to monitor cancer growth in these men and determine if treatment is needed.

Scientists at the ICR and The Royal Marsden Hospital conducted a pilot study of a technique called diffusion-weighted MRI to scan 50 patients at their initial prostate cancer diagnosis and at a follow-up appointment an average of two years later.

Each scan was then used to calculate a figure called an Apparent Diffusion Coefficient, a measurement of water movement within tissue. The team had previously shown that these measurements are significantly lower in patients with high-risk tumours, but this is the first time they have been calculated for men under Active Surveillance.

By their follow-up appointment, 17 men had required treatment as their cancer had progressed, while 33 men remained under Active Surveillance. The team found that diffusion-weighted measurements fell between the two scans in men who progressed to treatment, but remained similar for men still under Active Surveillance.

“The scans clearly showed which men’s cancers were progressing,” says study leader Professor Nandita deSouza. “If the technique continues to show promise in larger-scale studies, it could one day save men under Active Surveillance from the discomfort and potential complications of regular biopsies.”