Abstract Background Improvements in breast cancer treatment and care have resulted in improved outcomes and decreased mortality. These improvements, however, come with great expense. Despite efforts from health care systems, a significant proportion of the population remains uninsured. The uninsured population is often underprivileged, undereducated and more likely to come from racial/ethnic minority groups. This combination of factors results in a delay in diagnosis, presentation at later stage, and decreased access and compliance with treatment. The goal of the current study is to describe a method for treating an uninsured, underprivileged breast cancer population and the resulting outcomes. Methods Retrospective review was performed of all breast cancer patients seen at Maricopa Medical Center, the safety net hospital in Phoenix, AZ. All breast cancer patients seen from January 1, 2000 to December 31, 2020 were included. Baseline data for every patient was compiled prospectively, supplemented by retrospective chart review. The data included sociodemographic information, health literacy assessment, and diagnostic tests. Health literacy was assessed using the Newest Vital Sign (NVS). Breast cancer treatment, follow up, and mortality were documented. Beginning on July 1, 2006 a new process was implemented to facilitate care of uninsured patients. More details will be included in the poster presentation. Briefly, however, core needle biopsies were performed in the Breast Clinic by the Breast surgeon or Physician assistant during the initial consultation. Rather than requiring full payment of the planned operation upfront, instead a down payment was made with a plan for payment in installments of the remainder of the cost. For chemotherapy and targeted therapy, a process was implemented to apply for discounted medications for appropriate regimens. There are no radiation therapy facilities at Maricopa Medical Center. An agreement was therefore made with a Radiation oncology group in Phoenix to provide discounted radiation therapy. The treatment was paid through treatment grants as well as fundraising activities by the Health Foundation of the hospital. In 2011, the Breast surgeon underwent training for genetic counseling at City of Hope Medical Center to provide genetic counseling for these patients. Results A total of 1,797 patients were included. Among them, 661 patients were seen before the process (BP) was started, while 1,136 patients were seen after the new process (NP) was implemented. Overall, the mean age of the patients was 52 years with most patients being Hispanic (56%). On average the patients had 10 yrs of education and 18% had adequate health literacy. The majority of patients were not employed (70%) and completely uninsured (56%) or underinsured (31%). Only 18% of patients underwent screening mammography and as a result 67% of patients presented at stage II or later. Despite the barriers mentioned above, the NP group underwent a higher percentage of breast conservation procedures (75% versus 47%, p < 0.001). A higher percentage of the NP group received adjuvant therapy: Chemotherapy (91% vs 70%, p < 0.001), Radiation therapy (91% versus 70%, p < 0.001), and initiated endocrine therapy (87% versus 67%, p < 0.001). At a mean follow up of 8 years, these improvements in adjuvant therapy resulted in a lower incidence of both ipsilateral breast tumor recurrence and chest wall recurrence (2% vs 16%, p < 0.001 and 5% versus 8%, p = 0.21, respectively) and improvement in overall survival (90% vs 81%, p < 0.001). Conclusions Despite treatment of a population with many barriers to breast cancer management, implementation of a treatment process improved access to diagnosis and surgical therapy as well as recommended adjuvant therapy. These improvements resulted in lower local recurrence rates and improved survival in an uninsured population. Citation Format: Ian Komenaka, Trevin Reyes, Jacqueline Gilbert, Chiu-Hsieh Hsu, Waqas Arslan, Gilbert Ramos, John Dover, Herbert Hitchon, Jesse Nodora, Elena Martinez. A successful method for treatment of an uninsured underprivileged breast cancer population [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-09-10.