Adherence evaluation of endocrine treatment in breast cancer: methodological aspects.
BACKGROUND
Current studies on adherence to endocrine therapy in breast cancer patients suffer from methodological limitations due to a lack of well-validated methods for assessing adherence. There is no gold standard for measuring adherence. The aim of our study was to compare four different approaches for evaluating adherence to anastrozole therapy for breast cancer with regard to concordance between methods.


METHODS
Outpatients with early breast cancer treated with anastrozole completed the multi-method assessment of adherence. We implemented a self-report scale (the Simplified Medication Adherence Questionnaire), physician- ratings, refill records and determination of anastrozole serum concentration.


RESULTS
Comparison of the four approaches using Spearman rank correlation revealed poor concordance across all methods reflecting weak correlations of 0.2-0.4. Considering this data incomparability across methods, we still observed high adherence rates of 78%-98% across measures.


CONCLUSIONS
Our findings contribute to the growing body of knowledge on the impact that methodological aspects exert on the results of adherence measurement in breast cancer patients receiving endocrine treatment. Our findings suggest that the development and validation of instruments specific to patients receiving endocrine agents is imperative in order to arrive at a more accurate assessment and to subsequently obtain more precise estimates of adherence rates in this patient population.
Department of Psychiatry and Psychotherapy, Innsbruck Medical University, Anichstraße 35, 6020, Innsbruck, Austria.
Anne S
AS
Oberguggenberger
Monika
M
Sztankay
Beate
B
Beer
Birthe
B
Schubert
Verena
V
Meraner
Herbert
H
Oberacher
Georg
G
Kemmler
Johannes
J
Giesinger
Eva
E
Gamper
Barbara
B
Sperner-Unterweger
Christian
C
Marth
Bernhard
B
Holzner
Michael
M
Hubalek
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000077384:Anastrozole; D018931:Antineoplastic Agents, Hormonal / Q000097:blood / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy*; D003625:Data Collection / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008875:Middle Aged; D009570:Nitriles / Q000097:blood / Q000627:therapeutic use*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D013997:Time Factors; D014230:Triazoles / Q000097:blood / Q000627:therapeutic use*; D016903:Drug Monitoring
D018931:Antineoplastic Agents, Hormonal; D009570:Nitriles; D014230:Triazoles; D000077384:Anastrozole