77 Background: Several studies have attempted to explore treatment refusal in patients with cancer (CA). We performed a study that focused on patients with advanced CAs, characterizing those in this group that refused therapy. Based on this study, we sought to determine if some variables significantly correlated with ‘no treatment’ decisions, compared with a group of similar patients who accepted therapy. Methods: Our inclusion criteria were patients aged 18-75 years, diagnosed with stage IV CAs (per the American Joint Committee on Cancer staging) between 1/1/2010 and 12/31/2015 and refused therapy (Cohort 1). A randomly selected group of patients with stage IV CAs who accepted treatment in the same timeframe were used for comparison (Cohort 2). We used Proc SurveySelect and a simple random sampling method to create Cohort 2. Geisinger Health System’s data was used. Results: We found 508 patients for cohort 1, and 100 patients for cohort 2. The significance level was < 0.05. Female sex was associated with treatment acceptance (51/100, 51.0%) compared with refusal (201/508, 39.6%); p = 0.03. There was no association between treatment decision and race, marital status, BMI, tobacco use, previous CA history, or family CA history. Government-funded insurance was associated with therapy refusal (337/508, 66.3%) than acceptance (35/100, 35.0%); p < 0.0001. Cohort 1 had an older population compared with cohort 2 (p < 0.0001). The mean age of cohort 1 was 63.1 years (standard deviation (σ) 8.1), and 59.2 (σ 9.9) in cohort 2. The most common malignancy site in both cohorts was the respiratory system but this was not related to treatment decisions. Patients with pancreatic CA tended to refuse treatment (p = 0.0009). Only 19.1% (97/508) in cohort 1 were referred to palliative medicine, with 18% (18/100) in cohort 2; p = 0.8. There was an insignificant trend for patients who accepted treatment to have more comorbidities per the Charleston Comorbidity Index (CCI) (p = 0.08). The mean CCI in cohort 1 was 6.5 (σ 3.7), and 8.0 (σ 3.9) in cohort 2. Treatment of psychiatric disorders after CA diagnosis was inversely associated with treatment refusal (p < 0.0001). Conclusions: Male sex, older age, government-funded health insurance, and pancreatic CAs were associated with treatment refusal in advanced CA patients. Those who refused treatment were not increasingly referred to palliative medicine. Treatment of psychiatric disorders after CA diagnosis was associated with treatment acceptance.[Table: see text]