Psychosocial determinants of adherence with oral anticancer treatment: 'we don't need no education'

Given the potentially fatal consequences of inadequate adherence with oral anticancer treatment in persons with cancer, understanding the determinants of adherence is vital. This paper aims at identifying psychosocial determinants of adherence to oral anticancer treatment.

We reviewed the literature on psychosocial determinants of adherence with oral anticancer treatment, based on published literature in English, from 2015 to present. Literature searches were performed in PubMed, Embase, Web of Science, Cochrane library, Emcare, and PsychINFO, with 'cancer', 'medication adherence', 'psychology', and 'oral anticancer treatment' as search terms. The obtained 608 papers were screened by two independent reviewers.

In the 25 studies identified, illness perceptions, medication beliefs, health beliefs, and depression were found to be the major psychosocial determinants of adherence to oral anticancer treatment; sociodemographic and clinical characteristics were found to be of no major importance. The quality of the identified studies as assessed by two independent reviewers was found to be acceptable overall. The majority of papers were from North America and focused on patients with breast cancer; sample size varied from 13 to 1371; adherence was assessed with questionnaires derived from various theoretical models, pill counts and electronic pharmacy records; illness perceptions reflecting adaptive coping, and medication beliefs reflecting high necessity and low concerns were found to be associated with adherence.

Psychosocial concepts are major determinants of adherence with oral anticancer treatment. 'Beliefs about medicines' and 'illness perceptions' in particular determine adherence with this treatment. Studies aiming at impacting adherence would benefit from interventions with a solid basis in behavioral theory in order to help health care providers explore and address illness perceptions and medication beliefs. Pre-consultation screening of adherence behavior may be a helpful supportive approach to improve adherence. Blaming the victim ('patients should be educated about the importance of adherence') is better replaced by encouraging health professionals to identify and address maladaptive psychosocial determinants of adherence.