Association of Potentially Inappropriate Medication and potential drug interactions with Toxicity and Adherence to AntiNeoplastic Treatment - Abstract
Background: Approximately half the patients diagnosed with cancer are ?70 years implying a greater risk of non-adherence to cancer treatment due to frailty. Objectives of this study were to investigate how many older patients completed taxane-based treatment and if potentially inappropriate medications (PIMs) or potential drug interactions (PDIs) were associated with increased treatment-related toxicity and/or decreased treatment adherence. Further, we investigated whether ECOG performance status (PS) or CARG score identified patients with higher risk of treatment-related toxicity. Methods: A prospective observational cohort study of patients aged ?70 years starting a taxane-based chemotherapy regimen for any solid cancer disease, except gastrointestinal cancer. Patient, tumor and treatment characteristics were registered at baseline. Treatment-related toxicity was registered baseline and after every treatment cycle. PIMs were registered using the EU(7) PIM list. PDIs were identified via the Lexicomp and the Micromedex Interaction databases. Differences in patient, tumor, and treatment characteristics were described according to treatment-related toxicity (grade 1-2 vs 3-4) and according to treatment completion. Univariate logistic regression analyses were performed to determine the relation of PIMs and PDIs with treatment-related toxicity and treatment completion. Results: Ninety-six patients with a median age of 75 years (range 70-88) were included. Fifty-nine patients (55.2%) experienced severe toxicity, and only 20 patients (20.8%) completed treatment without dose reductions or delays. PDIs were not associated treatment completion. PIMs were associated with non-completion of planned chemotherapy, OR 3.21 (1.09-9.42), p=0.03. Neither PIMs nor PDIs were associated with increased risk of grade 3-4 toxicity to treatment. PS and CARG score did not predict toxicity. Conclusion: A minor proportion of older patients complete their planed therapy, implying that more focus on selecting the optimal treatment for the senior patients is needed, and that a more thorough assessment is warranted. PIMs were related to non-completion of chemotherapy but not to treatment-related toxicity. Older patients with cancer are a heterogeneous group and should be assessed individually recognizing that low-grade toxicity might be of high significance. Treatment decisions should be based on shared decisionmaking, and studies are needed to guide clinicians and older patients with cancer in making optimal treatment choices, such as more carefully selection for treatment and improvement of their condition before treatment.