Patients’ Preferences and the Time to Finish Gonadotropin-Releasing Hormone (GnRH) Agonist and Antagonist Injections in Japanese Prostate Cancer Patients

Introduction Currently, androgen deprivation therapy (ADT) plays a key role in treating advanced prostate cancer, particularly in elderly patients. With the advent of gonadotropin-releasing hormone (GnRH) medications, ADT has shifted from surgical to medical castration. While GnRH agonists and antagonists remain mainstream treatments for prostate cancer, there has been no research comparing the burden each drug places on patients. Methods A study conducted at Yokohama City University Medical Center analyzed 851 hormonal injections administered between August 2018 and February 2019. The study evaluated the time from prescription to completion of injection, as well as the perceived physical and mental burden on patients. Results showed that injections of degarelix took significantly longer time to injection than other treatments. Leuprorelin 22.5 mg most effectively reduced outpatients' hospital visits, primarily due to its six-month dosing interval and convenient kit formulation. Degarelix required a longer process, including drug dilution and cooling of the injection site to prevent potential skin reactions, contributing to its extended administration time. Results In terms of patient burden, leuprorelin 22.5 mg was associated with the least discomfort, showing minimal difference from the oral formulation. One limitation of this study is that the method of leuprorelin administration in Japan (subcutaneous injection) differs from that in other countries (intramuscular injection). Conclusion In summary, the six-month leuprorelin 22.5 mg regimen reduces hospital time. Patient burden was also considered a factor in the selection of GnRH preparations.