The Use of Androgen Deprivation Therapy (ADT) and Chemotherapeutic Agents in New Zealand Men with Prostate Cancer

PURPOSE To assess the patterns of use of androgen deprivation therapy (ADT) and chemotherapeutic agents in New Zealand men with prostate cancer. METHODS Men diagnosed with prostate cancer between 2006 and 2011 were identified from the New Zealand Cancer Registry. Through data linkage with the Pharmaceutical Collection and the National Minimum Dataset information on subsidised anti-androgens, luteinising hormone-releasing hormone (LHRH) analogues, chemotherapeutic agents, and orchidectomy was retrieved. The frequency of ADT and chemotherapy use in the first year post-diagnosis was assessed by patients' age, ethnicity, and extent of disease at diagnosis. RESULTS The study population included 15,947 men diagnosed with prostate cancer, of whom 4978 (31%) were prescribed ADT or chemotherapeutic agents. ADT was dispensed for 72% of men with metastatic disease. Only 24 (0.2%) men received chemotherapeutic agents. Men with advanced (regional or metastatic) disease older than 70 were more likely to receive anti-androgens only and to be treated with orchidectomy compared with younger men. Māori and Pacific men (compared with non-Māori/non-Pacific men) were more likely to receive pharmacologic ADT, and Māori men were also more likely to be treated with orchidectomy. CONCLUSIONS It was expected that all men diagnosed with metastatic prostate cancer should be using ADT in the first year post-diagnosis. However, for more than one-fourth of men neither anti-androgens nor LHRH analogues were dispensed within this period. Chemotherapeutic agents were used very rarely, so it seems that both pharmacologic ADT and chemotherapy is under-utilised in New Zealand patients with advanced prostate cancer.