Trends in megestrol acetate prescription among Korean patients with biliary-pancreatic cancer and their impact.

85 Background: Chemotherapy-induced anorexia poses a significant challenge for cancer patients, particularly in biliary tract cancer (BTC) and pancreatic ductal adenocarcinoma (PDAC), known for their poor response to treatment. Megestrol acetate (MA), a commonly prescribed appetite stimulant, is associated with concerns regarding thrombosis and polypharmacy. Understanding the trends in MA prescription and its cascade effects is essential for optimizing cancer care. Methods: We conducted a retrospective cohort study using data from the Health Insurance and Review Assessment Service (HIRA) database in South Korea. The study included patients diagnosed with BTC and PDAC between 2008 and 2017. Prescription trends for MA, thrombosis events, anticoagulant prescriptions, and total parenteral nutrition (TPN) were analyzed. Statistical analysis included Chi-square tests and Kaplan-Meier estimates. Results: In our analysis of 41,670 patients with BTC and PDAC between 2008 and 2017, MA prescriptions increased notably, with PDAC patients rising from 7.85% to 51.84%. TPN prescriptions remained consistently high, especially among patients prescribed MA. For instance, in 2008, 94.71% of BTC patients prescribed MA received TPN, compared to 70.34% without MA. Similarly, in 2017, 87.56% of those prescribed MA received TPN, compared to 61.63% without MA. Among BTC patients with long-term MA prescriptions, 16.34% received anticoagulants, compared to 4.92% without MA (p<0.001). Among PDAC patients, 18.3% with long-term MA prescriptions received anticoagulants, compared to 7.12% without MA (p<0.001). Conclusions: The study highlights the escalating trend in MA prescriptions among BTC and PDAC patients, along with increased thrombosis diagnoses and anticoagulant prescriptions. These findings underscore the importance of understanding and managing the cascade effects of MA use and associated polypharmacy in optimizing cancer care and improving patient outcomes.