AUA 2018: Risk Stratification for Active Surveillance: mp-MRI

San Francisco, CA (UroToday.com) M. Minhaj Siddiqui, MD gave a talk on the role of multiparametric MRI in active surveillance (AS) for prostate cancer. AS has been demonstrated to be a safe and effective method to manage prostate cancer in properly selected men. AS involves regular follow-up with PSA, DRE, and repeat prostate biopsy. Progression rate to definitive treatment has been reported to range between 15-40%. It is unclear how much of “progression” is due to previously undiagnosed higher risk tumor vs. true progression of the tumor from low to higher risk.

MP-MRI with targeted biopsy helps improve the reliability of tumor sampling and prevents missed diagnosis of clinically significant disease.

A prospective study published in JAMA 2015 [1] analyzed 1003 men biopsied for suspicion of prostate cancer. All these patients underwent MRI and had targeted biopsies and standard 12-core biopsies performed on all men. A total of 248 (25%) men were diagnosed with intermediate/ high-risk cancer on targeted biopsy. However, 93/248 of these patients (38%) were diagnosed as no cancer or low risk disease on standard biopsy only. In the PROMIS study, 572 patients underwent MRI, 12-core TRUS, and transperineal saturation biopsy. This study clearly demonstrated the ability of MRI to risk stratify men with clinically significant prostate cancer.[2]

When examining the role of MPMRI vs. genomic test/biomarkers, it is likely that they are complementary to each other. MRI helps to localize and identify the most aggressive tumor. Biomarkers can provide deeper functional insight into the future potential of the tumor. Biomarker characterization is only as good as the quality of the tissue it is characterizing. 

Siddiqui concluded and stated that MPMRI has great utility for characterization of prostate cancer and can identify more aggressive disease in up to 40% of AS patients. MPMRI has a potential complementary role to tissue biomarkers as it helps to localize the optimal tissue to apply the biomarker analysis to. If one asks which step to do first, MPRMI makes the most sense.


Presented by: M. Minhaj Siddiqui, MD, University Maryland School of Medicine

References:
1. Siddiqui MM, Rais-Bahrami S, Turkbey B, et al. Comparison of MR/ultrasound fusion-guided biopsy with ultrasound-guided biopsy for the diagnosis of prostate cancer. JAMA. 2015 Jan 27;313(4):390-7. doi: 10.1001/jama.2014.17942.
2. Hashim U Ahmed et al. Diagnostic accuracy of multi-parametric MRI and TRUS biopsy in prostate cancer (PROMIS): a paired validating confirmatory study. Lancet. 2017 Feb 25;389(10071):815-822. doi: 10.1016/S0140-6736(16)32401-1. Epub 2017 Jan 20.

Written by:  Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre @GoldbergHanan at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA