FOIU 2018: Can MRI Replace Biopsy in Men on Active Surveillance?

Tel-Aviv, Israel (UroToday.com) Arnauld Villers, MD presented and explained his support of multiparametric MRI (mpMRI) replacing biopsy in men on active surveillance (AS) of prostate cancer (PC). According to the EAU guidelines, there are considerable variations among studies regarding patient selection, follow-up schedule, and the use of confirmatory or repeat biopsy and MRI.

There are several unanswered questions raised by the introduction of mpMRI in AS. Can per-protocol repeat biopsy at 1 year be avoided for men on AS and replaced by:

Per protocol mpMRI before biopsy at one year, and then at X years?
For cause only MRI during follow-up, if PSA kinetics are suspicious?
Followed by targeted biopsies if mpMRI shows a lesion with a PIRADS score of above 3?
Is mpMRI sufficient to detect disease progression?

In a series of 196 men on AS with targeted biopsies of visible MRI tumors – 18% progressed to Gleason score 3+4 from Gleason score 3+3.¹ In another series, 152 men on AS with targeted biopsies of visible tumors at mpMRI, a total of 22.4% progressed from Gleason score 3+3 to Gleason 3+4. For MRI prediction of progression, the positive predictive value was calculated as 53% and the negative predictive value was 80%.²

According to the most recent EAU guidelines, mpMRI should not solely replace repeat biopsy during AS. Moreover, the use of mpMRI prior to any follow-up biopsy is not supported by any strong evidence. Robust data on the use of repeat mpMRI instead of repeat biopsy in AS is currently lacking.³ However, in patients considered for AS, using mpMRI and targeted biopsies at entry is associated with a progression rate of 14-16% at 2 years.⁴

In conclusion, low-risk men with negative mpMRI may have indeed favorable outcome on AS, regardless of the extent of low-grade cancer at biopsy. The follow-up strategy still relies mainly on clinical and biopsy assessment. It is based on serial digital rectal examinations (at least once a year), PSA (at least once every 6 months), and repeated biopsy (at a minimum interval of 3-5 years). MPMRI cannot be used as a stand-alone tool to trigger follow-up biopsies.³

References:
1. Nasin, J Urol 2017
2. Watson-Diaz, J Urol 2015
3. Briganti A. EAU position on active surveillance. Eur Urol 2018
4. Thurtle. BJU Int. 2018

Presented by: Arnauld Villers, MD, Lille University, France

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre @GoldbergHanan at the 2018 FOIU 4th Friends of Israel Urological Symposium, July 3-5. 2018, Tel-Aviv, Israel

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