Patients' Adherence in the Maintenance Therapy of Children and Adolescents with Acute Lymphoblastic Leukemia

Background: Acute lymphoblastic leukemia (ALL) is the most common form of paediatric cancer. Maintenance therapy as last treatment phase includes oral chemotherapy with methotrexate (MTX) and mercaptopurine (6-MP), self-or parent-administered at home, given for about 1 1/2 years, and qualified as decisive for an optimum therapy outcome. The aim of our study was to analyze factors influencing the adherence of patients with ALL undergoing maintenance therapy and their families. Methods: A multi-method study was undertaken between 11/2011 and 10/2014 with patients surveyed by the Hannover Medical School outpatient clinic, including a questionnaire survey and qualitative interviews with parents as well as blood samples of the patients. Results: 33 questionnaires, 27 interviews and blood samples of 26 patients could be analyzed. Only one third of the blood samples showed concentrations of the 6-MP active metabolite within the therapeutic reference range. Parents named the clinical doctor as their main advisor on medication intake. 36 % (12/33) of the participants stated that medication intake has not always occurred the way medication was prescribed. Drug formulation and drug intake information could be identified as determinants of adherence. Parents' problems to obtain information are partly caused by different study results concerning the correct timing of the drug intake and drug interactions with milk products. Conclusion: Parents' information on drug therapy should be more consistent and the pharmaceutical formulations have to be adapted to patients' needs to improve adherence and thereby the chance of long-term remission.