SUO 2017: The Institutional Learning Curve For Prostate MRI And MRI-US Fusion-targeted Biopsy: Improvements In Cancer Detection Over Time Based On 1400 Prostate Biopsies

Washington, DC (UroToday.com) Introduction: While MRI-US Fusion-targeted biopsy (MRF-TB) allows for improved targeting and detection of clinically significant prostate cancer (PCa), a concerning proportion of clinically significant disease is still missed on MRF-TB. In this study the authors evaluated the impact of the learning curve associated with MRF-TB in detection of PCa on cancer detection rates (CDR) over time as well as the outcomes of repeat MRF-TB in men with continued suspicion for cancer.

Methods: This was a secondary analysis of 1813 prostate biopsies in a prospectively acquired cohort of men presenting for prostate biopsy over a 4-year period. All men underwent pre-biopsy MRI and were assigned a maximum MRI suspicion score (mSS). Men with an MRI abnormality underwent combined MRF-TB and systematic biopsy (SB). The Cochran-Armitage Trend Test was used to calculate the relationship between operator experience and CDR. Biopsy outcomes between initial and repeat biopsy were evaluated for Gleason upgrade rates and newly detected cancer.

Results: Cancer detection rate increased 27% over time with increased institutional experience in men with mSS 4 and 5 lesions. Increased operator experience significantly correlated with detection of Gleason ≥ 3+4 PCa over time. Out of 108 men who underwent repeat MRF-TB, 35% were upgraded, with 47% due to increase in Gleason score and 53% due to newly detected PCa. 53% of men with mSS 4 and 5 lesions were upgraded compared to only 23% of men with mSS 1 and 2 lesions on repeat biopsy.

Conclusion: Increasing cancer detection rate over time and high upgrade rates on repeat MRF-TB demonstrate the significant learning curve associated with MRF-TB. This study demonstrates, despite its retrospective design and obvious selection bias, that men with low risk or negative biopsy results with persistent concerning lesions on MRI should be promptly re-biopsied. However, improved targeting accuracy with operator experience can help decrease the number of missed clinically significant PCa.

Presented by: Xiaosong Meng, New York, USA

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, @GoldbergHanan, at the 18th Annual Meeting of the Society of Urologic Oncology, November 29-December 1, 2017 – Washington, DC