The impact of opioid use prior to pancreatic cancer diagnosis on overall survival: Insights from SEER-Medicare data.

e16424 Background: Pancreatic cancer has a poor prognosis, with a 5-year survival rate of only 9%. Pain is one of the most common symptoms, often requiring opioid prescriptions for management. Prior studies have reported mixed findings on post-diagnosis opioid use and survival, but the impact of pre-diagnosis opioid use remains largely unexplored. This study evaluates the effect of pre-diagnosis opioid use on survival outcomes. Methods: This retrospective cohort study used the SEER-Medicare database to evaluate overall survival among patients diagnosed with pancreatic cancer between 2011 and 2017. Eligible patients who were either stage 3 or 4, were categorized into three groups: chronic opioid users, acute opioid users and non-opioid users. Chronic opioid use was defined as having an opioid supply for more than 90 days within a 120-day period, while acute opioid use was defined as having a supply of less than 90 days within the same period, both measured within one year before diagnosis. Patients were required to be continuously enrolled in Medicare Parts A, B, and D for at least one year. The primary endpoint was overall survival, defined as the time from the date of pancreatic cancer diagnosis to the date of death from any cause or the last follow-up date. Kaplan-Meier survival analysis was used to evaluate overall survival between groups. Cox proportional hazards models were used to adjust for potential confounders, including demographic and clinical characteristics. Descriptive analyses and chi-square tests were applied for baseline characteristics. Results: Among 2,035 patients with newly diagnosed cancer, 68.11% used opioids in the year prior to diagnosis. Of these 39.12% and 28.99% were classified as acute and chronic users, respectively. Cox proportional hazards analysis revealed that patients with pancreatic cancer in the tail had a lower mortality risk compared to those with tumors located in the head of the pancreas (aHR = 0.75, 95% CI: 0.62–0.91, p = 0.0046). Older age was associated with increased mortality (aHR = 1.37, 95% CI: 1.16–1.61, p < 0.0001 for age 70–74; aHR = 1.21, 95% CI: 1.03–1.41, p = 0.014 for age > 75). Not receiving chemotherapy (aHR = 1.21, 95% CI: 1.03–1.42, p = 0.01) or surgery (aHR = 1.80, 95% CI: 1.53–2.12, p < 0.0001) increased the risk of mortality. Both chronic (HR = 1.25, 95% CI: 1.069–1.462, p = 0.0052) and acute opioid use before diagnosis (aHR = 1.21, 95% CI: 1.05–1.40, p = 0.0087) were associated with worse survival compared to non-users. Conclusions: Pre-diagnosis opioid use, regardless of chronicity, is associated with worse survival outcomes in pancreatic cancer patients, emphasizing the need for careful evaluation of opioid use patterns and their potential impact on treatment adherence and survival. More work is needed to establish the mechanistic underpinnings of opioid-related mortality in patients with pancreatic cancer.