Abstracts from the New England Section of the AUA 2020: A Virtual Experience

© The Canadian Journal of Urology TM : International Supplement, August 2020 3 Urine Derived Lymphocytes Demonstrate Marked Differences in the Expression of Immune Checkpoint Molecules PD1 and NKG2A between Non-muscle Invasive and Muscle Invasive Bladder Cancer John R. Heard, MS , Andrew Charap, BS, John Sfakianos, MD Icahn School of Medicine at Mount Sinai, New York, NY Introduction: Lymphocytes in the urine of patients with muscle invasive bladder cancer (MIBC) have been found to be representative of those in the tumor microenvironment. Given this relationship, we hypothesized that analysis of immune checkpoint molecules on these cells may reveal differences between the microenvironment of non-muscle invasive bladder cancer (NMIBC) and muscle invasive bladder cancer (MIBC). The checkpoint molecule PD1 is the target of numerous monoclonal antibody treatments for MIBC and its role in suppression of the immune response to cancer has been well studied. The novel checkpointmoleculeNKG2Aisan inhibitoryreceptorfoundonNKandTcellsandNKG2A blocking monoclonal antibodies are currently in clinical trials for other cancer types. We sought to better understand the immune modulatory landscape of NMIBC and MIBC by studying urine derived lymphocyte expression of PD1 and NKG2A. Materials & Methods: In this study, urine was obtained from patients diagnosed with bladder cancer prior to receiving treatment. Patients were sorted into disease groups based on the pathology results from staging cystoscopy (NMIBC n = 4, MIBC n = 6). Urine was collected via void at office visit or catheterization prior to cystoscopy or cystectomy. On the same day as collection, urine derived cells were isolated by centrifugation, treatedwith ACK lysis buffer for removal of erythrocytes, stained, and analyzed via flow cytometry. Statistical analysis between groups was calculated using unpaired 2-tailed student’s t-test. Results: There were significant decreases in the ratio of both NK cells and T cells to total urine cells for the MIBC group (p < 0.05, p < 0.05). The percentage of CD4+ and CD8+ T cells expressing PD1 was significantly higher in the MIBC group (p < 0.05, p < 0.005). The NMIBC group was found to have an increased percentage of CD8+ T cells expressing NKG2A (p < 0.05). Analysis of lymphocytes expressing both NKG2A and PD1 found a significant increase in this phenotype among CD4+ and CD8+ T cells in the MIBC group compared to NMIBC (p < 0.05, p < 0.01). Conclusions: We conclude that it is feasible to detect differences in the urine lymphocyte composition and immune checkpoint profile between NMIBC and MIBC. Our analysis revealed increased expression of inhibitory marker PD1 on T cells from the urine of MIBC patients, suggesting the tumor microenvironment in MIBC is more inhibitory and contains moredysfunctionalTcellsthenNMIBC.Conversely,the inhibitoryreceptorNKG2A,whose role in tumor immunology is still under investigation, was expressed by fewer CD8+ T cells in MIBC compared to NMIBC. However, CD4+ and CD8+ T cells expressing both PD1 and NKG2A were present in a higher proportion for the MIBC group. These differences may reflectdisparities inthemechanismof immunemodulationbythetumormicroenvironment between these two diseases. *Max K. Willscher Award Eligible 1* 2 The Impact of Partial versus Complete BCG Intravescial Therapy on Bladder Cancer Outcomes in High-risk Non-muscle Invasive Bladder Cancer (NMIBC): Implications for Global BCG Shortages Michael E. Rezaee, MD, MPH 1 ,A.Aziz Ould Ismail, MD, MS 2 , Chiamaka L. Okorie, BSc 3 , Kristine E. Lynch, PhD 4 , Florian R. Schroeck, MD, MS 5 1 Dartmouth-Hitchcock Medical Center, Lebanon, NH; 2 VAMedical Center, White River Junction, VT; 3 Geisel School of Medicine at Dartmouth, Lebanon, NH; 4 VA Salt Lake City Health Care System and University of Utah, Salt Lake City, UT; 5 White River Junction VA Medical Center, White River Junction, VT Introduction: Adjuvant intravesical Bacillus Calmette-Guérin (BCG) is used to reduce disease recurrence and progression in patients with high-risk non-muscle invasive bladder cancer (NMIBC). Unfortunately, repetitive global shortages of BCG have disrupted guideline-recommended intravesical therapy practices for many high-risk patients. BCG instillations have been rationed (i.e., partial induction), so at least those at highest risk for disease recurrence and progression can undergo BCG treatment. The impact of delivering fewer BCG instillations than currently recommended has not been thoroughly evaluated. The purpose of this study was to assess the association of partial vs. complete BCG induction with bladder cancer outcomes in patients with high-risk NMIBC. Materials&Methods: This isaretrospectivecohortstudyofVeteranswhowerediagnosed with high-risk NMIBC (high grade (HG) Ta, T1, or Carcinoma in Situ) between 2005 and 2011 who received at least one dose of adjuvant BCG during a 6 month intravesical therapy window after diagnosis. Patients were categorized into partial BCG induction (< 5 BCG instillations) versus complete BCG induction (>= 5 BCG instillations) groups. Propensity score adjusted regression models were used to assess the association of partial BCG induction with risk of disease recurrence and bladder cancer death, stratified by Ta vs. T1 disease. Associations with progression to invasive disease (T1/T2) or bladder cancer death were evaluated among those diagnosed with HG Ta disease. Results: Among 540 patients with high-risk NMIBC, 114 (21.1%) received partial BCG induction, while 426 (78.9%) received complete BCG induction. This reflected a mean of 2.8 (SD 1.2) versus 6.0 (SD 0.8) induction doses per patient, respectively. Baseline patient characteristics did not differ significantly between groups. Partial vs. complete BCG induction was not significantly associated with increased risk of disease recurrence for patients with HG Ta (cumulative incidence ([CIn] 46.6% vs. 53.9% at 5 years, p = 0.38) or T1 (CIn 47.1% vs. 56.7 at 5 years, p = 0.19) disease. Similarly, partial vs. complete BCG induction was not significantly associated with increased risk of bladder cancer death for patients diagnosed with HG Ta (CIn 4.7% vs. 5.4% at 5 years, p = 0.87) or T1 (CIn 10.0% vs. 11.4% at 5 years, p = 0.77) disease. Among patients diagnosed with Ta disease, partial vs. complete BCGwas not significantly associatedwith risk of progression to invasive disease (T1/T2) or bladder cancer death (CIn 13.1% vs. 19.0% at 5 years, p = 0.37; Figure Panel 1). Conclusions: Patients with high-risk NMIBC who underwent partial BCG induction experienced similar bladder cancer outcomes compared to those who received complete BCG induction.ThesefindingssuggestthatareducednumberofadjuvantBCG instillations inthe inductionperiodmaybeanalternativetreatmentstrategyforsomehigh-riskpatients, particularly during global shortages of BCG. Figure 1 : Cumulative incidence plots showing the probability of disease recurrence, bladdercancerdeath,andprogression to invasivedisease(T1/T2)byBCG inductionstatus. WITHDRAWN 2 Scientific Session I: Oncology I