[Adherence to adjuvant hormonal therapy in patients with breast cancer]

Adherence to hormonal therapy (HT) treatment is a complex and multifaceted issue that can determine variations in response to treatment. However, it is little known about it in routine clinical practice.

To assess adherence to HT from 1 to 5 years of 190 patients treated at the Hospital de Clínicas (in Montevideo, Uruguay), and to identify factors for the interruption of therapy.

190 patients treated with HT due to S I-III breast cancer were included from 2002 to 2012. The Kaplan Meier method was used to assess the proportion of patients who discontinued HT, and the univariate analysis with log-rank test was used to identify factors leading to its interruption.

Out of 190 patients enrolled in the study, 95.3, 87.9, 80.6, 76.4, and 69.5% were still complying with their HT by the first, second, third, fourth and fifth year, respectively. Therapy continuity was greater in patients who received HT combined with tamoxifen and aromatase inhibitors vs. those who received a single drug (p = 0.017).

This real-life evaluation showed that HT adherence was reduced by 30.5% at 5 years, despite that there is a well-known benefit of this treatment on overall survival (OS), that it is well-tolerated, and provided for free. In view of the significant impact that HT interruption may have on OS, further investigation is required to determine what cause patients to discontinue their HT, in order to guide our efforts and enable us to increase and optimize adherence.