The authors identified 800 patients at their institution undergoing MRI-ultrasound fusion biopsy and further identified 209 patients on AS with at least two fusion biopsies between December 2013 and November 2016 or patients on AS prior to their first MRI and biopsy. Men with National Comprehensive Cancer Network (NCCN) very low-risk and low-risk criteria were included. Gleason upgrade was defined as detection of Gleason score ≥3+4. The proportion of patients experiencing upgrade on systematic biopsy, fusion biopsy, or both techniques was tabulated. Associations of clinical, pathologic, and imaging characteristics with biopsy upgrade were examined using descriptive characteristics and multivariable logistic regression. Among these 209 patients, 73 (35.0%) had at least two targeted biopsies (66% very low-risk and 34% low-risk disease). The time interval between biopsies was 12.6 months (IQR 11.2-17.7). The median PSA and PSA density were 5.4 ng/mL (IQR 4.2-7.1) and 0.11 ng/mL/mL (IQR 0.07-0.18), respectively. Twenty-one (29%) patients experienced Gleason upgrade on subsequent biopsy. Of those, 6 (8%), 5 (7%), and 10 (14%) had upgrade on systematic biopsy only, fusion biopsy only, and both systematic and fusion biopsy, respectively. Patients with upgrade on subsequent biopsy had higher PSA (p=0.02) and PSA density (p=0.02), greater number of positive systematic cores (p=0.001), and were among low-risk disease population (p=0.03). In logistic regression models including PSA density, and NCCN risk groups, greater number of positive cores in systematic biopsy (OR 1.88, 95%CI 1.23-2.92, p=0.005) was associated with the total Gleason upgrade on repeated biopsy.
In summary, among men with favorable-risk prostate cancer managed with AS, Gleason upgrade was detected in a 29% of patients on a second MRI fusion biopsy including both targeted and systematic regions. These findings appear to support the continued use of MRI fusion biopsy during surveillance due to risks of reclassification over time.
Presented by: Walter Hsiang, BS
Co-Authors: Kamyar Ghabili MD, Jamil Syed MD, Kevin Nguyen MS, Alfredo Suarez-Sarmiento MD, Michael Leapman MD and Preston Sprenkle MD
Affiliation: Yale School of Medicine Department of Urology, New Haven, CT
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