Adherence and discontinuation of oral hormonal therapy in patients with hormone receptor positive breast cancer.

Background: Oral treatment in women with breast cancer has been increasingly used. However, a potentially negative side of oral medication is poor patient adherence and/or discontinuation, which reduces the treatment effectiveness, accelerating progression of the disease and reducing the patient survival rate.
Aim of the Review: To compare the rates of adherence and/or discontinuation and the methodologies used to assess these outcomes. It was conducted an integrative review of original articles published from 2000 to 2012, in which their primary outcome was to quantify medication adherence and/or discontinuation of oral hormonal therapy in patients with hormone receptor positive breast cancer.
Methods: Original studies were searched in the PubMed/MEDLINE, Scopus, Embase and SciELO databases. The Medical Subject Heading was used to define descriptors. The descriptor "breast neoplasms" was used in all combinations. Each of the descriptors "medication adherence" and "patient compliance" were combined with each of the following descriptors "tamoxifen", "aromatase inhibitors", "selective estrogen receptor modulators", or the terms "letrozole", "anastrozole", and "exemestane".
Results: Twenty-four original articles were included. Our study showed a wide range of adherence and discontinuation rates, ranging from 45-95.7 and 12-73 %, respectively. Regarding the methodological development of the selected articles, a high prevalence (87.5 %) of prospective and/or retrospective longitudinal studies was found. In addition, there was a high prevalence of studies using a database (70.8 %). Among some of the studies, it was shown that patient adherence to hormonal therapy gradually reduces, while discontinuation increases during the treatment.
Conclusions: It was observed a great diversity among rates of adherence and/or discontinuation of hormonal therapy for breast cancer, which may be due to a lack of methodology standardization. Therefore, adequate and validated methods to ensure reliability of the results and allow comparison in the literature are needed. Furthermore, adherence decreases and discontinuation increases over time, suggesting the need for patient continuous education and a pharmacotherapeutic follow up by health professionals to improve these clinical outcomes.