Adherence to hormone therapy in patients with mCRPC: psychometric validation of the A-HT questionnaire

The incidence rate of prostate cancer (PCa) in many Western countries is high, contributing greatly to the cancer disease bur-den. In most cases, patients progress to metastatic disease defined as castration-resistant prostate cancer after androgen deprivation (mCRPC) following primary treatment where the majority of patients receive first-line new-generation oral hormonal therapies (HT) such as Abiraterone Acetate (AA) and Enzalutamide (ENZ). Despite the importance of correct intake of these drugs, adherence in patients with mCRPC is still poorly investigated and managed with measures not specific to this population. A self-report questionnaire was developed and validated with women with breast cancer treated with oral HT (A-BET). Therefore, this study aims to test the psychometric properties of this instrument on patients with mCRPC treated with AA or ENZ. A prospective observational validation study. The questionnaire was completed by all participants and again after 7/10 days by a randomized subsample to assess stability. Sixty-six patients completed the study (mean age of 72.8 years) and 31 completed the re-test (mean age of 72.7 years). Content validity reported excellent results. Cronbach's alpha of each item showed a strong correlation. Validation of an instrument to measure adherence to HT in patients with mCRPC can be a valuable tool for health professionals involved in patient care. In addition, having a population-specific validated instrument allows to make comparisons between results from different observations.