Purpose: Currently 5% of all available antineoplastic drugs and 20% to 25% of those in development are oral formulations. Common misconceptions about oral therapy are that it simplifies delivery of care and that it is associated with fewer adverse events (AEs), both of which are not always true. Furthermore, the onus of treatment delivery shifts from the clinic to the patient, sometimes creating problems regarding medication adherence. Risks of nonadherence include compromised treatment efficacy and risk of increased toxicity. We reviewed the use of oral antineoplastic therapy at the Providence VAMC with the aim of identifying ways to improve safety and adherence.
Methods: We conducted a retrospective chart review. Patients were included if they were prescribed an oral antineoplastic agent, excluding hormonal therapy, from November 2008 until November 2013. Demographic and clinical data collected included age, sex, number of household inhabitants, comorbidities, number of prescribed medications, oral antineoplastic agent, type of cancer, treatment intent (curative vs palliative), documentation of medication adherence, and documentation of AEs Data were then evaluated for patterns and issues specifically related to adherence and AEs.
Results: We identified 170 patients who were prescribed a nonhormonal oral antineoplastic therapy from November 2008 until November 2013. The most commonly prescribed medications were capecitabine, etoposide, and hydroxyurea. Medications with the highest rates of nonadherence were capecitabine (11/35; 31%), hydroxyurea (10/27; 37%), and sorafenib (3/11; 27%). Furthermore, 50% of all patients taking capecitabine experienced AEs, half of whom needed to discontinue or switch treatment.
Conclusions: As the number of oral antineoplastic therapies increases, optimizing adherence is a growing area of concern. Our data show that one-third of patients exhibited nonadherence to treatment. The most common reasons for nonadherence were AEs and difficulty following complex dosing schedules. Based on this quality assessment project, we propose moving forward with a quality improvement project to evaluate whether targeted interventions can improve medication adherence. Suggested interventions include providing additional written patient education materials with information on dosing schedule, indications to call the physician, and/or a follow-up telephone call to inquire about adherence and AEs.
