Adherence to endocrine therapy in women with breast cancer: development and preliminary validation of the A-BET questionnaire

Abstract

Purpose. To develop an Italian tool that measures the therapy adherence of women with breast cancer undergoing treatment with oral endocrine therapy. Methods A two-phase study was conducted, which followed the guidelines of the European Statistical System for the development and validation of a questionnaire. In the first phase, the questionnaire was developed; in the second phase, a preliminary validation was carried out on patients with breast cancer undergoing treatment with oral hormonal therapies. Results In its final version, the questionnaire presents 6 main items which aim to investigate the level of adherence, the degree of awareness of the nature of the drug taken and the reasons that may influence nonadherence. 82 patients were recruited in the validation study, with an average age of 56.4 years, while for the re-test 40 were selected with an average age of 57.3 years. Content validity reported excellent results. Cronbach's alpha of each item showed a strong degree of correlation. Conclusions. The creation of a tool for measuring adherence to endocrine therapy in breast cancer patients can be a valuable support for healthcare professionals involved in their care. Future studies should be aimed at using A-BET (Adherence – Breast Endocrine Therapy) on larger cohorts of patients in order to verify its validity / reliability more accurately and to be able to generalize the results.