From the Dana-Farber Cancer Institute; Patient Safety Center, University Medical Center, Utrecht, The Netherlands; and the Departments of Medicine and Epidemiology, and the Rowan Breast Center, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA
Authors’ disclosures of potential conflicts of interest are found at the end of this article.
Address reprint requests to Angela DeMichele, MD, MSCE, Co-Director, Rowan Breast Center, Abramson Cancer Center, University of Pennsylvania, 3 Perelman Center, 3400 Civic Center Blvd, Philadelphia, PA 19104; e-mail: Angela.demichele{at}uphs.upenn.edu
Overview: With the increasing development and marketing of oral therapies for cancer, the issue of patient nonadherence has become an increasingly important one to the oncology community. Poor adherence can have a significant detrimental effect on clinical trial results and on "real-world" patient outcomes, affecting both the efficacy and effectiveness of medications. In a variety of patient populations, nonadherence has been associated with increased costs, including more physician visits, higher hospitalization rates, and longer stays. When patients participating in clinical trials are nonadherent, inaccurate conclusions may be drawn regarding toxicity and efficacy. Poor adherence to an oral experimental agent has the potential to strongly bias results if the control is a placebo or an intravenous therapy. Barriers to adherence can be attributable to the individual, culture, or system within which the individual receives care. On the individual level, theories of control and learning are frameworks that can provide insight into why individuals have difficulty adhering to oral chemotherapy regimens. Patients from certain cultural backgrounds may share particular beliefs about the nature of cancer that affect adherence behaviors. Contextual system factors, such as treatment protocols, dispensing procedures followed by pharmacies, availability of health education or medication counseling, number of other concurrent medications and possible drug interactions, and the patient's ability to pay for the medication may also affect adherence. Strategies to address adherence in chronic medical conditions, such as cancer, often consist of informational interventions, behavioral interventions, or a combination of both. Methods to improve adherence in children and adolescents requires a specialized approach.
