3040 Brachytherapy Boost Underutilized in Underprivileged Minorities with Unfavorable Risk Disease Despite Superior Survival to External Beam Radiotherapy J. Kodiyan, M. Ashamalla, A. Guirguis, and H. Ashamalla; New York - Presbyterian Brooklyn Methodist Hospital, Brooklyn, NY Purpose/Objective(s): Despite greater recurrence free survival with brachytherapy boost (BT) in unfavorable risk prostate cancer, BT con- tinues to be underutilized in favor of dose escalated external beam radia- tion therapy (EBRT). We investigated overall survival (OS) and utilization patterns for BT in unfavorable disease cohorts using the National Cancer Database (NCDB). Materials/Methods: The NCDB was queried for men with prostate adenocarcinoma diagnosed between 2004 and 2013. All included pa- tients had unfavorable intermediate, high or very high risk (IR, HR, and VHR respectively) disease based on clinical T stage, clinical Gleason score, and PSA. Analyzed patients had a minimum 4-years follow-up and must have received either EBRT +ADT (antiandrogen therapy), EBRT +BT, or EBRT+BT+ADT. Patients with metastatic or nodal disease were excluded. Two groups were created based on receipt of BT and appropriately balanced using calculated propensity scores. OS of matched cohorts was analyzed using Kaplan-Meier sta- tistics and Cox proportional hazards regression models. Multivariate logistic regression was applied to the unmatched cohort to determine predictors for BT utilization. Results: Of 1,294,126 cases identified, 15,347 were selected for anal- ysis, with median follow-up time of 5.6 years (range, 4-12 years). Median age 69 (range, 37-90). Among 6,780 matched cases, BT-con- taining therapies were associated with significantly greater OS, 71% vs 58% at 10-years (log-rank p<0.001, HR 1.17, 95%CI, 1.03-1.34, pZ0.01). Predictors for improved OS included lack of comorbidities (HR 0.78, 95%CI, 0.64-0.95, pZ0.02) and IR over HR (HR 0.33, 95% CI, 0.23-0.46, p<0.001), while no significant difference in survival was observed between HR and VHR. Age groups 60-65 (HR 0.34, 95%CI, 0.13-0.91, pZ0.03) and 66-70 (HR 0.36, 95%CI, 0.14-0.94, pZ0.03) were predictors for better OS compared to age<60 (reference). Age 71- 90 trended toward improved OS compared to age<60, but did not reach significance (HR 0.53, 95%CI 0.23-1.22, pZ0.14). Variables signifi- cantly predicting for receiving BT included white or Asian race (OR 1.25, 95%CI, 1.13-1.39, p<0.001), treatment in community setting (OR 1.2, 95%CI, 1.11-1.3, p<0.001) or outside the Northeast (OR 1.75, 95%CI, 1.59-1.93, p<0.001), and high income (OR 1.25, 95%CI, 1.13-1.39, p<0.001). Significant predictors for not receiving BT include being uninsured (OR 0.28, 95%CI, 0.18-0.41, p<0.001) and age>60 (OR 0.57, 95%CI, 0.52-0.63, p<0.001). IR disease had the greatest odds of receiving BT (OR 1.4, 95%CI, 1.24-1.57, p<0.001), followed by HR (reference), then VHR (OR 0.63, 95%CI, 0.55-0.71, p<0.001). Conclusion: Despite superior overall survival with brachytherapy boost than with dose escalated external beam radiotherapy in unfavorable risk prostate cancer, it remains underutilized in African Americans, the unin- sured or low income, in aggressive disease (HR or VHR) and in patients >60 years old. Author Disclosure: J. Kodiyan: None. M. Ashamalla: None. A. Guirguis: None. H. Ashamalla: None. 3041 Are Oncologists Leaving Smaller Practices over Time? M. Lam, 1 , 2 J. Figueroa, 2 E.J. Orav, 3 and A. Jha 2 ; 1 Brigham and Women’s Hospital / Dana Farber Cancer Institute, Boston, MA, 2 Harvard T.H. Chan School of Public Health, Boston, MA, 3 Brigham and Women’s Hospital, Boston, MA Purpose/Objective(s): Medicare and private payers have increas- ingly shifted their methods of reimbursing healthcare providers from fee-for-service to alternative payment models. During the same time, and some argue in response to, there is some evidence that hospitals and physicians have been coming together to form larger organizations. However, we know very little about how these national trends have affected consolidation among medical and radiation oncologists. Materials/Methods: For 2013 and 2017, we identified medical and radiation oncologists in Physician Compare tied to individual or group practices. Physicians in the database have submitted a Medicare claim within the prior year, have at least one specialty, and are associated with at least one practice. A group practice is defined by the number that the physician uses to submit claims (not by employment status) and the data include every group practice in which a physician has practiced during the previous twelve months. We identified providers who identified as medical or radiation oncologists. We calculated the size of each oncology group practice. We allowed oncologists to be counted in more than one practice. We used the number of oncologists within each group to estimate the proportion of total oncologists practicing in various group sizes (solo oncologist, 2-10, 11-50, 51-99, 100+). Results: There were a total of 2,795 and 2,637 unique practices with 13,641 and 15,561 medical oncologists in 2013 and 2017. The mean number of medical oncologists per practice was 4.8 in 2013, rising to 5.8 in 2017. Practices with a single medical oncologist fell by 7% (1,173 to 1,086 practices) and those with 2-10 medical oncologists fell by 9% (1,370 to 1,242 practices). During the same period, practices with 11-50 and 51-100 medical oncologists increased by 40% (227 to 267 practices) and 14% (19 to 33 practices). There were a total of 1,620 and 1,603 unique practices with 5,556 and 6,222 radiation oncologists in 2013 and 2017. The mean number of radiation oncologists per practice was 3.4 in 2013 and 3.9 in 2017. Practices with a single radiation oncologist and 2-10 radiation on- cologists decreased by 6% (600 to 563 practices) and 1% (945 to 933 practices). During the same period, practices with 11-50 and 51-100 ra- diation oncologists increased by 43% (73 to 104 practices) and 50% (2 to 3 practices). Conclusion: We found that the number of oncologists e both medical and radiation e practicing in small groups is declining over time. These findings suggest that the oncology community does not appear to be im- mune from the broader national trends toward greater physician consoli- dation. These findings raise important issues about the impact of rising consolidation on the quality and costs of oncology care. While larger practices may be providing better value, more empirical evidence is needed on the impact on patient care. Author Disclosure: M. Lam: None. J. Figueroa: None. E.J. Orav: None. A. Jha: None. 3042 Population Density and Facility Type Influence Management of Prostate Cancer A.R. Lankford, 1 C.S. DiBiase, 2 S.K. Srivastav, 3 N.D. Scherzer, 1 J. Silberstein, 1 and S.J. DiBiase 4 ; 1 Tulane University School of Medicine, New Orleans, LA, 2 The Webb School of Knoxville, Knoxville, TN, 3 Tulane University Department of Global Biostatistics and Data Science, New Orleans, LA, 4 Department of Radiation Oncology, Weill Cornell Medical College, New York, NY Purpose/Objective(s): Men with localized prostate cancer have several conventional management options. Which option a patient chooses is likely influenced by multiple factors. In this study, we investigated the role of population density and facility types on first course treatment for men with localized prostate cancer in the United States. Materials/Methods: Using the National Cancer Database, we identified men who were diagnosed with localized prostate cancer from 2004- 2015. The U.S. was divided into three groups based on codification of population size and urbanization by the United States Department of Agriculture Economic Research Service: metropolitan, urban, and rural. To assess facility type influences, facilities were classified by the International Journal of Radiation Oncology  Biology  Physics E456