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EAU 2018: Prostate MRI Reveals More Clinically Significant Cancers, Reduces Overdiagnosis Compared to Standard Biopsy

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Key Points

  • The researchers found that 71 (28%) of the 252 men in the MRI arm of the study avoided the need for a subsequent biopsy.
  • Of those who needed a biopsy, the researchers detected clinically significant cancer in 95 (38%) of the 252 men, compared with 64 (26%) of the 248 men who received only the TRUS biopsy.

A large international study has shown that magnetic resonance imaging (MRI) can reduce the number of invasive prostate biopsies by up to 28%. The PRECISION trial showed that using MRI to target prostate biopsies leads to more harmful and fewer harmless prostate cancers being diagnosed. The results were presented at the European Association of Urology (EAU) Congress in Copenhagen, with simultaneous publication by Kasivisvanathan et al in The New England Journal of Medicine.

First author of the study Veeru Kasivisvanathan, MRCS, of University College London, said, “PRECISION is the first international multicenter randomized trial to show the benefits of using MRI at the start of the prostate cancer diagnosis process. In men who need to have investigation for prostate cancer for the first time, PRECISION shows that using an MRI to identify suspected cancer in the prostate and performing a prostate biopsy targeted to the MRI information leads to more cancers being diagnosed than the standard way that we have been performing prostate biopsy for the last 25 years.”

Caroline Moore, MD, FRCS (Urol), Reader in Urology at University College London and senior author of the study, commented, “We compared standard prostate biopsy to the use of MRI, offering targeted biopsies to only those men who had a suspicious MRI. The MRI pathway detected more harmful cancers that needed treatment, and it reduced overdiagnosis of harmless cancers, even though fewer men had a biopsy in the MRI arm.”

Background

Prostate cancer is currently diagnosed by examining biopsy samples taken from the prostate via a procedure called transrectal ultrasound guided prostate biopsy (TRUS), which involves taking around 10 to 12 samples from the prostate using a probe with a special needle. It is uncomfortable, costly, and carries a slight risk of infection, and because it involves estimating the position of a possible tumor, tumors may also be missed by this method. The PRECISION study investigated whether an MRI scan can avoid the need for biopsy in some patients or give better diagnostic information where a biopsy is necessary.

Method

Researchers from 23 centers randomly allocated 500 men to be examined either with a standard 10 to 12 core TRUS biopsy, or with an initial MRI scan followed by a targeted biopsy if the MRI showed an abnormality. The main aim was to assess what proportion of men were diagnosed with clinically significant prostate cancer (defined as a Gleason Grade of ≥ 3+4). It also aimed to assess the proportion of men who were diagnosed with clinically insignificant cancer (Gleason Grade 3+3).

Results

The researchers found that 71 (28%) of the 252 men in the MRI arm of the study avoided the need for a subsequent biopsy. Of those who needed a biopsy, the researchers detected clinically significant cancer in 95 (38%) of the 252 men, compared with 64 (26%) of the 248 men who received only the TRUS biopsy.

“This shows that a diagnostic pathway with initial MRI assessment followed by biopsy when required can not only reduce the overall number of biopsies performed, but can give more accurate results than TRUS biopsy alone. We also found that patients who had MRI had fewer side effects than those who just had the standard TRUS biopsy. This is because the MRI allows some men to avoid biopsy and in those who need one, is able to better indicate which area of the prostate needs to be investigated, so you don’t need to randomly sample the whole prostate and can use fewer biopsy cores,” explained Dr. Kasivisvanathan.

Several elements need to be considered for MRI to be generally adopted in the diagnostic process. As Dr. Kasivisvanathan said, “The ability to perform good quality MRI and the ability to interpret the MRI information are specialist skills. We will therefore need appropriate training for clinicians to use the technology and changes in health services to increase availability and capacity to perform prostate MRI. In the long-term, this new diagnostic pathway can be cost-effective. Costs can be saved by the reduction in the number of men undergoing biopsy in the first place, by the earlier diagnosis of harmful cancers, and in the avoidance of the diagnosis of harmless cancers.” 

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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