Fatores associados com não adesão ao tratamento com tamoxifeno em paciente com câncer de mama : um estudo de intervenção da atividade farmacêutica.

Abstract

Breast cancer (CM) is a public health problem, and the most common type of neoplasm is in women worldwide. For CM with positive estrogen receptor has as a treatment hormonal therapy, in which the pioneer was for tamoxifen (TAM) and continuous being widely used. It is effective to reduce recurrence and mortality, but a term for its treatment is long, at least 5 years, and could impair adherence. Non-adherence generates a potential problem in the treatment efficacy of patient and economic issues for health institutions. Thus, understanding the adherence as dependent variable, the objectives of this dissertation are: to estimate the effects of the pharmaceutical activity of education on adherence behavior and pharmacotherapeutic knowledge of the drug TAM in patients with CM of the Integrated Oncology Center (COI); to describe the sociodemographic, socioeconomic, clinical, behavioral characteristics, characteristics of pharmacotherapy, health and service of women with CM that attend at COI; to evaluate an association of sociodemographic, socioeconomic, clinical, behavioral factors, characteristics of pharmacotherapy, health and service with no treatment; to identify the factors associated with non-adherence to TAM therapy for CM and to evaluate how TAM drug interactions with CYP2D6 inhibitors (cytochrome P450 family 2 subfamily D member 6) of these patients. The study presents an almost experimental design of pre and post-treatment measures with non-equivalent group control that also originates cross-sectional studies. The sample is composed of women aged ≥ 18 years, with diagnosis of CM, that uses TAM medicine for over 6 months, and who are applied to the COI health service. The results of this study were: Pharmaceutical intervention had no influence on adherence, however, potentiated the knowledge of the TAM drug of the patients by increasing the number of correct answers, promoting clarification of side effects and forgetfulness of dose; The proportion of women who joined the therapy was 60% (95% confidence interval (IC): 0.50-0.70). The probability of adhesion decreases with younger women (≤49 years), with development of side effects such as hot flashes, fluid retention and myalgia; and present 2˃ side effects. After multivariate logistic regression analysis only the side effects liquid retention remained significantly less likely to become adherent; Thirty-two percent (95% IC: 0.23-0.41) of patients use a CYP2D6 inhibitor concomitant with TAM and among these 41% (95% IC: 0.23-0.59) are non-adherent. Concomitant use of fluoxetine with TAM negatively influences the adherence of hormone therapy in the treatment of breast cancer. It was concluded that the pharmaceutical intervention had a positive effect in the CM patients. Factors such as age, number of side effects e developed and specific side effects influence the adherence rates of CM patients. More than 1/3 of women do not adhere to hormone therapy and concomitantly use CYP2D6 inhibitors with TAM. In the interdisciplinary team, the pharmacist is essential and need to intensify health care practices focused on these patients.