MRI Guided Biopsy to Find “Hidden” Prostate Tumors

Why do some men with elevated prostate specific antigen (PSA) levels who are carefully monitored and undergo repeated negative biopsies still develop aggressive prostate cancer? Clinical researchers at Princess Margaret Hospital (PMH) in Toronto, Canada believe they can now answer that baffling question.

The answer, they say, is hidden tumors located on the top of the prostate that evade traditional diagnostic procedures, including ultrasound-guided needle biopsy. The PMH research, published online today in the British Journal of Urology International (BJU 8938), demonstrates that magnetic resonance imaging (MRI) is the best tool to reveal such tumours.

“Our findings identify a specific high-risk group whose tumors are difficult to diagnose because of location. These men benefit from MRI, which guides the biopsy procedure with a high degree of accuracy,” says author Dr. Nathan Lawrentschuk, Urologic Oncology Fellow, PMH Cancer Program, University Health Network.

MRI machine

“The research team calls the clinical presentation of elevated PSA and repeated negative biopsy results in ‘prostate evasive anterior tumor syndrome’ (PEATS).”

This use of MRI is not foolproof but it is a significant advance. A team of urologists, surgeons, radiologists and pathologists studied 31 PMH patients who had positive biopsy results and tumors on top of their prostate as shown on MRI. They found that MRI was able to help diagnose hidden prostate tumors 87% of the time.

Dr. Lawrentschuk says clinicians need to be aware of PEATS because these hidden tumors can be aggressive.


Princess Margaret Hospital, Toronto, Canada is a member of University Health Network, which also includes Toronto General Hospital and Toronto Western Hospital. All three are research hospitals affiliated with the University of Toronto. Their research arm is Ontario Cancer Institute.

Link to ABSTRACT of the publication

The role of magnetic resonance imaging in targeting prostate cancer in patients with previous negative biopsies and elevated prostate-specific antigen levels.


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Edited by J. Strax 10/08/09