Orally Administered Cancer Therapy: Breaking Down Barriers to Adherence and Quality of Life.

Abstract

Over the past 2 decades, many orally administered cancer therapy options have become available.1 As of 2010, 20% to 25% of cancer therapeutics in development were oral formulations,2 and the number of oral therapies has increased dramatically over the past decade with the addition of small-molecule biologics.1 Possibly in part because intravenous medications are often perceived to increase medical complications, inconvenience, cost, and poor quality-of-life (QoL), studies have confirmed that many patients prefer oral to intravenous chemotherapy,3,4 This has, in turn, led to trials comparing the efficacy and outcomes of oral versus intravenous therapies because patients did not want to sacrifice efficacy for convenience.4 Although many comparative trials have shown equal or better outcomes with oral therapies,3 several challenges remain, including patient safety, monitoring of adverse effects, and medication adherence.5 Adherence is a global medical issue across disease sites.6 Within cancer care, the earliest reports of nonadherence rates were documented in breast cancer with endocrine therapies, ranging from 12% to 59% with tamoxifen and 9% to 50% with aromatase inhibitors.7 In a systematic review by Greer et al,1 adherence estimates were widely variable among studies (49%–100%), due to the diverse methods for assessing adherence, lack of standardization in defining optimal adherence, considerable differences in length of follow-up, and poor quality of studies. Nonetheless, poor adherence rates have been confirmed and have been linked to downstream consequences, such as poorer clinical outcomes, development of medication resistance, increased consumption of healthcare resources, and lower QoL.7,8 Therefore, clinicians need to identify barriers to adherence and establish standard protocol and documentation procedures for prescribing oral therapeutic agents, educating patients on appropriate use, monitoring adverse effects, and tracking adherence.1 Barriers to adherence are multidimensional and include patient-related factors (comorbidities, cognitive abilities, and health literacy), disease-related factors (severity of symptoms, points of progression of disease), therapy-related factors (complex regimens, inconsistent prescription labelling, drug–drug or drug–food interactions, adverse effects), healthcare-related factors (inadequate training, ineffective communication), and social and economic factors (limited insurance, lack of access to good care).1,2 Ideally a standardized, comprehensive oral cancer therapy delivery program should be developed that can be tailored to the patient and their specific barriers. However, few intervention studies have been effective, due to methodological concerns.1 Only 1 of 12 intervention studies reviewed by Greer et al1 may have had an effect on adherence. This signifies the need for further knowledge of what factors have the most impact on adherence. In this issue of JNCCN, Jacobs et al9 aimed to measure adherence rates of patients on oral cancer therapies across various cancer types, identify the physical and psychological symptoms of these patients, and describe correlates to adherence and QoL. They hypothesized that poor adherence would likely be associated with