Abstracts from the Abstracts from the Mid-Atlantic Section of the AUA 2021

© The Canadian Journal of Urology TM : International Supplement, October 2021 Moderated Poster Session 1: Prostate Cancer AReviewof SpaceOARComplications and Influential Patient Characteristics E. Mann, A. Quinn, C. Clark, N. Bowler, M. Mann, J. Mark, C. Lallas, R. Den, E. Trabulsi Sidney KimmelMedical College at Thomas JeffersonUniversity, Philadelphia, PA, USA Introduction and Objective: Approved by the FDA in 2015, SpaceOAR injections are a recent advancement to minimize rectal toxicity for prostate cancer treatment with radiotherapy. There is a paucity of literature examining complications of the procedure. We reviewed our experience of SpaceOAR placement for occurrence of complications and examined patient characteristics related to outcomes. Methods: We conducted a retrospective review of 233 patients who underwent SpaceOAR placement at our academic hospital by four surgeons and one radiation oncologist between 2018-2021. Variables such as demographics, oncologic parameters, radiation plan, and radiographic assessment of hydrogel placement were recorded. The Charlson Comorbidity Index (CCI) was used to assess comorbidity risk. Results: Of the 233 patients who received SpaceOAR, 25 (10.7%) experienced toxicity. All complications were mild (Grades 1-2) and transient. 7 patients experienced pelvic pain post placement, 5 experienced hematuria, 1 experienced rectal bleeding, 1 experienced urinary retention requiring straight catheterization, 8 experienced lower urinary tract symptoms, 1 experienced mild stress urinary incontinence, 1 experienced pelvic fullness, 2 experienced hemorrhoids, 4 experienced a change in bowel frequency, and 1 experienced a TIAa fewhours after placement. For patients who experienced complications, the average CCI was 3.16; in the groupwithout complications, the average CCI was 3.56 (p=NS). The patients without complications did have a higher BMI on average compared to those with (28.9 vs. 26.78, respectively (p=0.039145)). A total of 16 patients (6.9%) had some portion of the hydrogel injected into the rectal wall, which was never clinically significant. Conclusions: SpaceOAR placement is well tolerated with a low incidence of toxicity or related complications. Toxicity was mild (Grades 1-2) and transient in the majority of patients. Injection of hydrogel into the rectal wall was infrequent and was not clinically significant. Overall, the procedure is well tolerated with low rates of procedure-related toxicity. Do 5-alpha Reductase Inhibitors Effect the Diagnostic Accuracy of MRI- Fusion Biopsies? E. Mann, K. Berry, A. Quinn, C. Clark, J. Mark, T. Chandrasekar, E. Trabulsi, C. Lallas, L. Gomella, M. Mann Thomas Jefferson University, Philadelphia, PA, USA Introduction and Objective: Use of 5-alpha reductase inhibitors (5-ARIs) in prevention of prostate cancer has been examined from many angles. We aimed to test the hypothesis that reduced prostate size by the use of 5-ARIs may increase the diagnostic rate of MRI-fusion prostate biopsies. Methods: Retrospective review of one institution identified 215 consecutive MRI-fusion biopsies, 25 of which, were noted to be taking a 5-ARI at time of biopsy. Chi squared and Fischer tests were used to assess the significance of differences between biopsy results of each set of patients. Results: 52% of the patients on 5-ARIs had positive MRI-fusion biopsies (77% clinically significantly positive, defined as greater than grade group 1, and 23% insignificant), and 48%were negative. Of patients not taking 5-ARIs, 64% had cancer (41% significantly positive and 59% insignificant) and 36% were negative. There was no difference in rates of cancer detection in any core based on whether a patient was taking a 5-ARI, chi square 1.4, p=.23. There was also no difference in cancer detection in MRI regions of interest (ROI) alone in those taking a 5-ARI and those who were not, Chi square .33, p=.23. There was a significant difference in detection of significant cancers vs. insignificant in patients taking 5-ARIs, Fisher exact test value of .0179, p<.05; when comparing patients with significant vs. insignificant cancer found in the ROI, the Fisher exact test value was .131 <.05. Conclusions: Although 5-ARIs do not impact accuracy of MRI-fusion biopsies in our small study, more significant cancers were found in patients on 5-ARIs when considering all cores. It may be that with a larger patient population, further differences would be borne out. We continue to collect data to further explore this as it may influence the use of these medications around diagnostic testing in the future. MP1-05 MP1-04 6