Abstracts from the New England Section of the AUA 2021

NE-AUA 2021 Abstracts 4 Social and Environmental Risk Factors at the Census Tract Levels for Patients Undergoing Radical Cystectomy for Urothelial Carcinoma in Rhode Island in the Last 20 Years Borivoj Golijanin, BS 1 , Sarah Andrea, PhD 1 , Justin Bessette, BS 1 , Rebecca Ortiz, BA 1 , Philip Caffery, PhD 1 , Timothy O’Rourke, MD 2 , Christopher Tucci, MS, RN-BC, CURN, NE-BC 1 , Ali Amin, MD 3 , Dragan J. Golijanin, MD 1 1 Minimally Invasive Urology Institute, The Miriam Hospital; The Warren Alpert Medical School of Brown University, Providence, RI, USA; 2 The Minimally Invasive Urology Institute, The Miriam Hospital; The Warren Alpert Medical School of Brown University, Providence, RI, USA; 3 Department of Pathology and Laboratory Medicine, The Miriam Hospital; The Warren Alpert Medical School of Brown University, Providence, RI, USA Introduction: Tobacco smoking and occupational exposure are well documented urothelial carcinoma (UC) risk factors. Potentially upstream neighborhood-level factors are underexplored. We examined the association between sociodemographic and pollution composition and incidence of UC treated by radical cystectomy (RC) and overall survival (OS) in Rhode Island. Materials &Methods: 484 patients underwent RC from 1/2000 to 12/2020 at Brown University affiliated hospitals. Patient addresses were linked to census tractlevel data on neighborhood sociodemographic composition and locations of leaking underground storage tanks, superfund sites, sanitary waste sites, and active solid waste facilities. Using Poisson and Cox proportional hazards models, we assessed incidence of RC and OS as a function of neighborhood pollution, area deprivation index (ADI), poverty, and racial composition quartiles in separate models adjusted for year and age at time of RC. Results: Average agewas 68 years, 73%men, and 90%white, with clinical stage T2 in 32%, Tis in 5%, Tx in 8%, and 3% had no information. Likelihood of RC positively correlated with greater neighborhood pollution (RR for 4th vs. 1st quartile:1.39, 95%CI:1.08,1.79), predominance of white population (RR for 4th vs. 1st quartile:1.94, 95%CI:1.41,2.66) and negatively with greater poverty (RR for 4th vs. 1st quartile: 0.44, 95% CI:0.33, 0.58). Five-year OS rate was 56%, in neighborhoodswith highest poverty rates (Q4) was 45%, and in neighborhoods with lowest rates of poverty (Q1) was 62%. ComparedwithQ1, the hazard ratio for those in Q4 poverty neighborhoods was 1.72 (95% CI:1.16,2.55). Conclusions: Inequalities in social determinants of health influence incidence and outcomes of UC patients undergoing RC. Patients undergoing RC were more likely to bewhite and living in affluent neighborhoods ( Figure 1 ), however, this could be an artifact of selective survival. Those living in neighborhoods with greater number of pollutants underwent RC at greater rates ( Figure 2 ). Risk of death in the first five years following RC was greatest for those living in neighborhoods with low socioeconomic status. Further research is needed to study contextual factors defining the differences in RC use and OS of patients withUC. Health policies and screening programs can target these high-riskUC hot-spots in order to improve earlier detection and patient outcomes. Standard Versus Extended Lymph Node Dissection at the Time of Radical Cystectomy for Bladder Cancer: Emulation of a Clinical Trial Alejandro Abello, MD, MPH 1 , Sumedh Kaul, MS 1 , Aaron Fleishman, MPH 1 , Joaquim Bellmunt, MD, MPH 1 , Irving Kaplan, MD 1 , Simon Kim, MD 2 , Peter Chang, MD, MPH 1 , AndrewWagner, MD 1 , Ruslan Korets, MD 1 , Aria Olumi, MD 1 , Boris Gershman, MD 1 1 Beth Israel Deaconess Medical Center, Boston, MA, USA; 2 University of Colorado, Aurora, CO, USA Introduction: It is uncertain whether lymphadenectomy (LND) provides a survival benefit in patients undergoing radical cystectomy (RC). In the only completed randomized trial on this topic - LEA AUO AB 25/02 - extended LND (eLND) was associated with improved survival compared to limited/ standard (sLND), although these associations did not reach statistical significance. Herein, we emulated a pragmatic clinical trial designed to resemble the LEA trial. Materials &Methods: We identified patients in the National Cancer Database who met the following eligibility criteria based on the LEA trial: adult 40-79 years old, Charlson 0-1, underwent RC with LND for high-grade cT1 / cT2- T4a cNany cM0 urothelial carcinoma of the bladder from 2006-2015, without neoadjuvant chemotherapy, at a hospital performing ≥16 RC/year. sLND and eLND were defined as removal of 4-11 and ≥12 lymph nodes based on the LEAtrial. Apropensity score (PS) was estimated for receipt of eLND, and the associations of LND type with overall survival (OS) were evaluated adjusting with inverse probability of treatment weights (IPW). Results: A total of 2248 patients formed the study cohort, including 436 with sLND and 1812 with eLND. Baseline characteristics were well-balanced after PS adjustment. During a median follow-up of 37.5 months, eLND was associated with significantly improved 5-year OS compared to sLND (60% vs. 48%; HR 0.72, 95%CI: 0.61-0.85, p<0.01; Figure 1 ). Effect estimates were consistent across all potential treatment effect modifiers, including cT stage, cN stage, and age ( Figure 2 ). Results were robust in sensitivity analyses that modified the definitions for LND and relaxed the annual RC hospital volume requirement. Conclusions: In observational analyses designed to emulate a completed clinical trial, eLND was associated with improved OS compared to sLND among patients undergoing RC. Survival and effect estimates were similar to those in the LEA trial but statistically significant due to larger sample size. 3 Scientific Session I: Oncology I 3