SUO 2017: Does MPMRI Perform Differently in Men Undergoing Targeted Biopsy for Evaluation Of Prostate Cancer Versus those on Active Surveillance?

Washington, DC (UroToday.com) Multi-parametric MRI (mpMRI) has becoming increasingly used in the diagnosis and management of prostate cancer, developing a role in the improved diagnosis and staging of localized disease. However, while the shine of the new technology has worn off to some degree, it remains an important tool in the arsenal of the urologist and urologic oncologist. 

As a result of the anatomic detail it provides, there has been utilization of mpMRI in men being evaluated for prostate cancer (pCa) and those with a diagnosis of prostate cancer but considering active surveillance (AS). While there is evidence supporting the use of mpMRI in both these groups of men (only in men with prior negative biopsy in the former group), this group compares the performance of mpMRI between these two groups. 

The authors identified a consecutive series of men who underwent MRI-US fusion biopsy of the prostate for the diagnosis of prostate cancer or men diagnosed with low-risk prostate cancer considering AS. Specifically, patients with PIRADS 3+ lesions then underwent targeted fusion biopsy, looking for detection rate of Grade Group 2 or higher (GG2+) pCa in targeted biopsies. The detection rate for PIRADS 3, 4 and 5 ROI’s were compared between the two groups. They then matched men from both cohorts based on age, PIRADS score, and year of mpMRI and repeated the analysis. 

Of the patients selected, 102 were being considered for AS, while 349 were undergoing evaluation for pCa diagnosis. The proportion of targeted biopsies that found GG2+ cancer in men in the AS cohort versus the evaluation cohort were 8.3% vs. 11.1% (p=0.540) for PIRADS 3, 16.9% vs. 35.8% (p=0.007) for PIRADS 4, and 36.8% vs. 44.1% (p=0.571) for PIRADS 5 ROI’s, respectively. After adjusting for relevant mpMRI and clinical risk factors, we found that that men in the diagnostic evaluation cohort had a higher likelihood of finding a GG2+ pCa in the targeted biopsy, compared to men on AS [OR 2.0 (95%CI: 1.2-3.5), p=0.01]. The association was primarily in men with no prior negative biopsy – likely because they received inappropriate diagnostic evaluation according to the guidelines; systematic biopsy alone would have picked up many of these cancers. 

Matching men by age, PIRADS score, and year of mpMRI left us 138 men in each group. Repeat analyses on the matched cohort continued to show an increased likelihood of GG2+ cancer on targeted biopsy in men undergoing evaluation for pCa, compared to men on AS [OR 2.1 (95%CI: 1.1-4.0), p=0.03]. 

Based on this, the authors concluded that targeted biopsy of similar risk ROI’s yielded more GG2+ cancer in men undergoing evaluation for pCa compared to those on AS. However, it is unclear if this changes management – will the authors reduce mpMRI in the AS cohort? What do the findings imply?

Limitations / Discussion Points:

1. These are two different clinical groups. With a diagnosis of PCa already, the patients considering AS are a more select group. The PPV of a test depends heavily on the population being tested.

2. It is unclear from the abstract if this was a targeted biopsy alone or systematic biopsy as well. Recent evidence suggests the negative predictive value of targeted biopsies alone is poor; systematic biopsies continue to pick up disease not found on targeted cores. 

3. The patient selection was very poorly worded. The AS cohort – are these patients being considered for AS or those on AS for some time? 

4. The patients being evaluated for prostate cancer diagnosis were a mix of men with prior negative biopsy (N=124) and no prior negative biopsy (n=225). Unfortunately, it has never been established in the latter setting. 


Presented by: Marcelo P. Barboza MD¹

Co-Authors:  Nachiketh Soodana Prakash MD MS¹, Isildinha M. Reis PhD², Feng Miao PhD², Maria C. Velasquez MD¹, Rosa Castillo MD³, Chad R. Ritch MD MBA¹, Mark L. Gonzalgo MD PhD¹, Bruce Kava MD¹, Ramgopal Satyanarayana MD¹, Dipen J. Parekh MD¹ and Sanoj Punnen MD MAS¹

Affiliation: ¹Department of Urology, University of Miami Miller School of Medicine, Miami, FL, USA; ²Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, USA; ³Department of Radiology, University of Miami Miller School of Medicine, Miami, FL, USA

Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, twitter: @tchandra_uromd at the 18th Annual Meeting of the Society of Urologic Oncology, November 20-December 1, 2017 – Washington, DC