e24062 Background: Advance care planning (ACP) is crucial for informed decision-making in patient care. However, barriers such as time constraints and discomfort with discussions hinder widespread ACP adoption. A previous study (Cohen et al. JNCCN 2023) indicated a low ACP engagement rate (17%), but participation in a palliative care program has shown potential to increase this proportion. Therefore, we sought to determine the prevalence of ACP and identify associated predictor factors among patients with cancer in Brazil enrolled in an outpatient palliative care (OPC) program. Methods: A retrospective analysis was performed from November 2022 to December 2023. Eligible patients were those who passed away during the study period and had received care from an OPC program at one of the largest private joint cancer centers in Latin America. We assessed the prevalence of ACP and explored its potential associations with clinical characteristics (age, gender and type of cancer), OCP support (follow-up period, appointments and family support), and end-of-life care (treatment in the past month, intensive care unit (ICU) admission in the past month, home care service referrals, and place of death).Comparative analyses involved two groups: those who had undergone ACP and those who had not (no-ACP). Logistic models were employed. Results: A total of 849 patients were included in the final analyses. Patients’ characteristics were well balanced between groups. Most patients were women (56%), with an average of 68.2 years (SD =15.3). Patients were mostly diagnosed with gastrointestinal (36%), breast (13%), and lung (13%) cancers. Notably, 43% of patients had ACP, significantly higher than literature controls (95% confidence interval [CI]= 22-31%, P = 0.001). Among the factors associated with ACP, clinical characteristics were not significant. However, OCP support and end-of-life care were significantly predicted by ACP, including the follow-up period (MACP= 179 vs. Mno-ACP= 101; P = 0.001), family support (MACP= 0.6 vs. Mno-ACP= 0.3; P < 0.001) , ICU admission at the last 30 days of life (ACP = 28% vs. no-ACP = 72%; P < 0.001), and home care service referral (ACP = 72% vs. no-ACP = 28%; P < 0.001). Conclusions: These findings underscore that prolonged engagement with the OPC program is associated with increased adoption of ACP among Brazilian patients with cancer. Given the scarcity of data from developing countries, our findings suggest that the OPC program plays a pivotal role in optimizing end-of life care support through ACP.