Hormonioterapia no câncer de mama: fatores associados à adesão e persistência ao tratamento

Abstract

Hormonetherapy in breast cancer is key to the transition from active treatment to survival of care, because it improves the long-term survival results, as well as providing a better quality of life for patients and reduce hospital costs. However, to achieve desirable results in the coping of the disease is important adherence and persistence to the recommended treatment. It is known that the adherence and persistence to hormonetherapy may be influenced by several factors related to the patient, treatment, health services, beliefs and lifestyle, but have been little explored to date. The conduct of research able to scale these phenomena and portray them in a defined context is an important strategy for comparison, comprehension and production of evidence for health services in order to promote the success of therapy used and improved quality life of the patient. The aim of this study was to evaluate the adherence and persistence adjuvant hormonal therapy and its associated variables in patients with treatment for breast cancer in a referral hospital in oncology of southeastern Brazil. We conducted an analytical study of character and longitudinal design, from the collection of secondary data from 182 women with breast cancer who started hormone therapy in 2009 at the Hospital of the Muriaé Cancer - MG/Fundação Cristiano Varella, following for 5 years. Information relevant to the study (dependent and independent variables) were collected from medical records and hormonetherapy of dispensing control, the Hospital of the Muriaé Cancer - MG/Fundação Cristiano Varella pharmacy sector. For the calculation of adherence and persistence were used methods "Medication Possession Ratio" and "Estimated level of Persistence", respectively. Were considered adherent to the treatment women with Medication Possession Ratio greater than or equal to 80% and persistent those who did not discontinue for 60 days or more. To analyze the factors associated with adherence, bivariate analyzes were performed using the statistical test Chi-square (χ2). The probability of persistence was calculated using the Kaplan Meier compared by log-rank test. To estimate hazard ratios and the level of significance of the variables associated with persistence, univariate and multivariate Cox regression analyzes were conducted. The method "backward elimination" was used by removing the variables that did not remain significant in the final model (p ≤ 0.05) and the diagnosis of Schoenfeld residuals test to assess the proportionality of the Cox models. The adherence rate among participants was 85.2% at the end of follow-up, and of these, 47.7% were persistent. The persistence was modified over time, with 85.5% in the first year of treatment and 43.6% at the end of the 5 years. The results of the bivariate analysis for association between adherence rate and independent variables studied was not significant for any of them. In the multivariate Cox model, women with advanced stage at diagnosis, who did not undergo surgery and with a high number of hospital admissions (≥ 3 hospitalizations) showed increased risk of discontinuation of hormone therapy. It is observed that despite the accession this cohort is considerable, as time progresses there is a progressive increase in non-persistent patients to treatment, influenced by characteristics related to the severity of the disease, increasing the risk of inadequate therapeutic response and worse results for the rate of survival and recurrence of the disease in these women.