Use of antipsychotic drugs during radiotherapy in adult cancer patients in Korea: A nationwide retrospective cohort study based on the health insurance review and assessment service database

Abstract Background Antipsychotic drugs (APDs) are used for treating mental illnesses and are also used by cancer patients. This study aimed to evaluate APD use in adult cancer patients who received radiotherapy (RT) in South Korea and assess the effects of APD use during RT on survival. Methods This retrospective cohort study utilized the Health Insurance Review and Assessment Service database of Korea. We included adult cancer patients who underwent RT or chemotherapy (CTx, cisplatin, or 5-Fluorouracil) between 2010 and 2020. The APDs included in the analysis were aripiprazole, quetiapine, olanzapine, risperidone, haloperidol, and chlorpromazine. Results Overall, 725,897 patients received RT, and 115,500 received concomitant chemo-radiotherapy (CCRT). Of them, 41,118 (5.6%) took APDs during RT, and 8,129 (7%) took APDs during CCRT. Overall, 27,789 (67.58%) patients who took APDs during RT were men, and 28,004 (68.2%) were aged ≥ 60 years. The most frequently used APD during RT was quetiapine (64.93%). The three cancer sites with the highest frequency of APD users during RT were the lungs (21.64%), breast (5.09%), and colorectum (4.44%). The three cancer sites with a high proportion of APD use during RT were the lungs (14.87%), brain (14.27%), and esophagus (12.95%). Patients who took APDs during RT had a higher mortality rate (HR: 3.45, p < 0.0001) compared to the non-APD patients. The patients taking high-dose APD had a lower mortality rate than those on low-dose APD (HR: 3.23 vs. 3.46, p < 0.0001). Conclusions Only 5.6% of patients who underwent RT used APDs, and quetiapine was the most frequently prescribed APD during RT. Patients who used APDs during RT had poorer survival than those who did not. Further studies are required to elucidate the effects of APDs on cancer patients. Trial registration: This study is retrospectively registered