e13515 Background: Reducing avoidable hospital and emergency department (ED) use are national priorities in cancer care. Acute care centers (ACCs) that expand access for patients with oncologic emergencies are increasingly implemented as alternatives to inpatient and ED care. The impact of these ACCs is uncertain. Additionally, how to rigorously evaluate these interventions and to iteratively improve their effectiveness remains unclear as infrastructure interventions such as ACCs are not amenable to experimental manipulation. Methods: We are developing a novel quasi-experimental framework for evaluating and improving the effectiveness of an ACC intervention at the Simmons Comprehensive Cancer Center (SCCC) of the University of Texas Southwestern. SCCC covers one of the largest geographic regions of any academic medical center in the country, creating challenges addressing access to care. Drawing on the Andersen model for healthcare utilization we hypothesize that ACC effectiveness is mediated through enabling factors, particularly distance. Our initial evaluation framework draws on an untreated control group design with multiple pretest and post-test samples. The control group is comprised of patients living in zip codes farther away from the ACC. Additional analytic work will assess the feasibility of adding a matching cohort group structure based on factors such as onset of illness and matching individual patient episodes based on risk adjustment parameters. If the ACC is later expanded to other sites, the design can be further developed by adding a switching replications methodology to augment the quasi-experiment. Data collection draws on claims data provided through SCCC’s participation in Medicare’s Oncology Care Model (OCM). Results: Over OCM’s initial four performance periods (each six months long), all-cause risk adjusted hospitalization rates for SCCC patients ranged from 25.2% to 27.2%. All-cause risk adjusted OCM ED use ranged from 28.1 to 29.9%. Seeking to improve performance for both, SCCC leadership initially implemented a temporary urgent care clinic in August 2018. This initial prototype clinic was formalized into an operational ACC in August 2020. Evaluation of the impact of this ACC intervention is ongoing. Conclusions: ACCs represent potentially important means to reduce avoidable hospital and ED use. However, complex infrastructure interventions are not amenable to experimental evaluations assessing their impact, and it remains difficult to gain insights into how to tailor services through these interventions to support patients with oncologic urgencies and emergencies. Quasi-experimental approaches when integrated alongside ACC interventions represent promising mechanisms of evaluation and continuous quality improvement.