Background: Multiple randomised clinical trials, including TROG9601 and TROG0304, have shown the oncological benefits of combining androgen deprivation therapy (ADT) and radiation therapy (RT) for prostate cancer.
Aims: We aim to evaluate the variations in the ADT use with RT at a population-based level in Australia and New Zealand.
Methods: This study included men enrolled in the Prostate Cancer Outcomes Registry Australia and New Zealand (PCOR-ANZ) who were diagnosed with intermediate-risk prostate cancer (IRPC) or high-risk prostate cancer (HRPC) between 2015 and 2022 and documented to have RT as primary treatment. The primary outcome is ADT utilisation. Covariables evaluated were jurisdictions, area of residence, socioeconomic status (SES), and treatment centres. Multivariable logistics regressions were used to identify covariables associated with ADT use. All analyses were performed separately for IRPC and HRPC.
Results: 14610 men were included in this study, of which 8611(59%) had ADT with RT – 40%(2870/7054) in IRPC, and 76%(5741/7556) in HRPC. There were large variations in ADT use between jurisdictions, ranging from 22% to 73% for IRPC (P<0.001) and 56% to 92% for HRPC (P<0.001). Men living in regional/remote areas were more likely than men in major cities to have ADT– 47%vs35% for IRPC (P<0.001), and 78%vs71% for HRPC (P<0.001). Men from highest SES quintiles were less likely to have ADT (30% for IRPC and 63% for HRPC) compared to the remaining four quintiles (P<0.001). Men treated in private institutions were less likely to have ADT compared to public institutions – 33%vs47% for IRPC (P<0.001), and 71%vs80% (P<0.001). In multivariable analyses, jurisdictions, area of residence, SES and treatment centres remained significantly associated with ADT use.
Conclusions: This is the largest contemporary Australasian series reporting on the pattern of ADT use with RT, with notable variations in practice.