Open Access Open Badges Research article

Influence of a patient information program on adherence and persistence with an aromatase inhibitor in breast cancer treatment - the COMPAS study

Volker Ziller12*, Ioannis Kyvernitakis12, Dana Knöll12, Astrid Storch12, Olaf Hars3 and Peyman Hadji12

Author Affiliations

1 Department of Gynecology, University hospital of Giessen and Marburg GmbH, Marburg, Baldingerstrasse, 35033 Marburg, Germany

2 Department of Endocrinology, Reproductive Medicine and Osteoporosis, University hospital of Giessen and Marburg GmbH, Marburg, Baldingerstrasse, 35033 Marburg, Germany

3 Olaf Hars Statistical Consulting, Berlin, Germany

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BMC Cancer 2013, 13:407  doi:10.1186/1471-2407-13-407

Published: 4 September 2013



It is known that suboptimal adherence rates may affect endocrine treatments for breast cancer, but little information has been reported whether any efforts to improve treatment adherence have been successful. We designed a randomized, controlled study to investigate the effect of oral or written patient information program on adherence and persistence when receiving an aromatase inhibitor (AI).


The study cohort included 181 female patients receiving an adjuvant AI treatment randomly assigned to one of three groups. The first group received reminder letters and information booklets, the second group was reminded and informed through telephone calls and the control group received neither. The primary endpoint was the rate at which patients were classified as adhering to treatment after twelve months.


Baseline results showed a well-balanced randomization with no significant differences between groups. After 12 months, 48% (CI 35–62) of the control group, 62.7% (CI 49–75) in the telephone group and 64.7% (CI 51–77) in the letter group were adhering to therapy. A post hoc pooled analysis with a one-way hypothesis for both interventions versus control indicated a significant difference between the groups favouring the intervention (p = 0.039).


The aim of this study was to investigate the efficacy of a simple and practical interventional program in enhancing adherence to breast cancer treatment. Patients receiving additional/supplemental information appeared to have an improved adherence rate even though the differences between groups were not statistically significant for the primary endpoint.

Adherence; Compliance; Aromatase inhibitors; Breast cancer; Endocrine treatment