Factors Affecting Androgen Deprivation Therapy Choice in Prostate Cancer Patients

The incidence of prostate cancer in Hong Kong almost tripled between 1996 and 2010, with the highest increased incidence rate in total forms of malignancy. The incidence of prostate cancer in Hong Kong increased up to 28.9 per 100,000 men in 2017 (Age-standardized rate) (Hong Kong Cancer Registry 2017) and ranked third in all men cancers in Hong Kong. Certain environmental elements have had an effect on the increased rate of prostate cancer, including the transition to Western dietary habits and an aging population because of the rise in average life expectancy. In addition to environmental causes, the medical development of laboratory diagnoses and wide prostate-specific antigen usage in Hong Kong have also contributed to the increase in diagnosis of prostate cancer in recent years. Certainly, the efforts from different health bodies in public education about the condition have helped to raise public awareness about the condition, which also increase the pick-up of early disease in Hong Kong.

Androgen deprivation treatment (ADT) has become the standard treatment for metastatic prostate cancer in the past decades. Androgen deprivation can be achieved by three main modalities, namely bilateral orchidectomy, gonadotropin-releasing hormone (GnRH) agonist and GnRH antagonist. Apart from injectable ADT, oral GnRH antagonist has been approved recently. ADT can be different in terms of mechanism of action, route of drug administration (injection vs oral), site of injection and frequency of drug administration. Each different formulation may contribute to patient's choice on their drug usage [1-3]. However, information regarding the preference of choice and factors affecting the choice of ADT formulation were not available in the literature. Therefore, in this study, possible factors that will affect patient's choice of ADT, reason and preference on their ADT choice will be investigated.

The objective of this study is to investigate possible factors that will affect patient's choice of ADT therapy. This is a cross-sectional study performed in Prince of Wales Hospital in Hong Kong. One hundred patients will be recruited for this study.

After obtaining informed consent, trained research staffs will assist the subjects to perform this cross-sectional survey. Information related to patients' background (including, but not limited to: age, educational level, work-status, living situation), disease background (stage of disease), concomitant drug usage & administrative frequency, preference on drug usage (ADT vs injection; frequency of drug administration), history of ADT usage, reason and preference on their ADT choice, will be collected from the survey.

Inclusion criteria

• Prostate cancer only happens in male patients
• Patients who are currently receiving at least one dose of LHRH agonist or antagonist, as androgen deprivation therapy
• Patients who are willing to consent and participate in this study

Exclusion criteria

• Patients who received bilateral orchidectomy as androgen deprivation therapy
• Patients who, in the opinion of investigators, are not able to comprehend about the study questions