SUO 2017: MRI Fusion Biopsy is Associated with a Higher Rate of Pathologic Downgrading at Radical Prostatectomy

Washington, DC ( MRI targeted fusion biopsy has higher sensitivity and specificity in predicting Gleason score compared with standard 12-core biopsy [1]. Dr. Beksac and co-authors presented results of their study assessing MRI fusion biopsy and pathologic staging at the time of radical prostatectomy. Gleason score discordance may still occur post radical prostatectomy, which can impact decision-making. The objective of this study was to analyze the patterns of Gleason downgrading after standard biopsy versus fusion biopsy.

The authors reviewed their institutional database to identify 589 prostate cancer patients who received a radical prostatectomy between February 2014 and October 2015. All preoperative biopsies were re-reviewed by a genitourinary pathologist. Gleason score concordance of biopsy and final pathology was compared between standard biopsy and fusion biopsy groups. Downgrading was defined as the change from Gleason Group 3, 4 or 5 on biopsy to Gleason Group 1 or 2 on RP pathology. Additional clinical and pathologic factors associated with downgrading were analyzed. Statistical analysis was performed using Student’s t-test or Mann Whitney U test for continuous variables and Chi-square or Fisher's exact tests for categorical variables. Multivariate analysis was done using a binomial logistic regression model.

There were no significant differences between the two groups (standard biopsy: n=476; fusion biopsy: n=104) in terms of PSA (p=0.49), PSA density (p=0.17), maximum % core (p=0.83), clinical stage (p=0.13), MRI volume (p=0.10) and MRI ECE (p=0.13). The fusion biopsy group had more patients who downgraded on final pathology compared with standard biopsy (18.5% vs. 9.7%, p=0.01) Downgrading did not impact pathological outcome. Downgrading was not associated with pathologic stage (p=0.53), extraprostatic extension (p=0.39), lymph node invasion (p=0.24), nor positive surgical margin status (p=0.41). A multivariate regression model including PSA, maximum % core, MRI volume and MRI ECE demonstrated that targeted biopsy was the only factor independently associated with downgrading after radical prostatectomy (p=0.01)

In summary, the authors observed increased downgrading from high/intermediate risk groups to low risk groups after fusion biopsy compared with standard biopsy. This information should be used in shared decision making for prostate cancer management.


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;313(4):390-397.

Presented by: Alp Tuna Beksac, MD¹

Co-Authors: Shivaram Cumarasamy MD², Akriti Gupta MD², Kanika Mahajan BDS, MPH², Ugo Falagario MD², Sonya Prasad BA², Isuru Jayaratna MD², Andrew Charap BS², Emma Rosenbluth BA², Sara Pasik BA² and Ash Tewari MD²

Affiliation: ¹Icahn School of Medicine at Mount Sinai, New York City, NY; ²Icahn School of Medicine at Mount Sinai, New York, NY

Written by: Zachary Klaassen, MD, Society of Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre @zklaassen_md at the 18th Annual Meeting of the Society of Urologic Oncology, November 20-December 1, 2017 – Washington, DC