Background: Japanese patients with prostate cancer are typically treated with primary androgen deprivation therapy (ADT), most commonly administered as a combination of a luteinizing hormone-releasing hormone (LHRH) agonist and an antiandrogen (AA). Since LHRH agonists and AA therapy can be maintained for several years, the long-term effects of these treatments on patients must be carefully considered, including the risk of concomitant central nervous system (CNS) conditions which could affect treatment choices. Objective: To describe CNS-related concomitant conditions during ADT and/or AA treatment and the subsequent healthcare resource utilization in Japanese nonmetastatic castration-resistant prostate cancer (nmCRPC) patients. Methods: Patients diagnosed with nmCRPC and CNS-related conditions while on ADT and/or AA therapy between April 2009 and August 2017 were retrospectively followed up for a maximum of 2 years using a claims database. Results: A total of 455 patients (average age, 78.5 years), were included. The 3 most common concomitant CNS-related conditions were pain (~60% of events), insomnia (~30%), and headache (2%-3%). The frequency of CNS-related conditions in these patients increased approximately threefold after starting AA therapy (before, 969 events; after, 2802). On average, a patient had 10 episodes of concomitant CNS-related conditions in a year. Medical costs did not significantly increase due to CNS-related conditions. Discussion: The most frequently reported CNS-related conditions were pain, insomnia, and headaches. Furthermore, more concomitant CNS-related conditions 1 year after CRPC diagnosis and 1 year after starting AA treatment were recorded. Conclusion: Patients with nmCRPC experience an increase in the frequency of concomitant CNS-related conditions, including pain, insomnia, and headaches, after CRPC diagnosis or starting AA treatment. Future research should explore the causes of this increased frequency.
Keywords: androgen deprivation therapy; antiandrogen; castration-resistant prostate cancer; central nervous system-related; gonadotropin-releasing hormone analogs.