The Relationship Between Guideline-Recommended Initiation of Therapy, Outcomes, and Cost for Patients with Metastatic Non-Small Cell Lung Cancer

BACKGROUND: Guideline-recommended therapy for metastatic non-small cell lung cancer (mNSCLC) encourages evidence-based treatment; however, there is a knowledge gap regarding the influence of guideline-recommended initiation of therapy on outcomes and cost. OBJECTIVE: To investigate if lack of guideline-recommended initiation of first-line systemic therapy was associated with worse patient outcomes and increased costs for patients with mNSCLC. METHODS: In this retrospective analysis, 1,344 Medicare patients with mNSCLC were identified from Humana data. Performance status (PS) was imputed using procedure, diagnosis, and durable medical equipment codes pre-index. Guideline-recommended initiation of therapy was defined as ≥1 cycle of National Comprehensive Cancer Network-recommended first-line therapy based on age and PS or targeted therapies regardless of age and PS. Demographics and clinical characteristics were compared by guideline-recommended initiation of therapy. A Cox model assessed factors associated with 6-month mortality. End-of-life quality of care indicators included hospital admission and oncology infusions 30 days preceding death and were evaluated using logistic regression models. A generalized linear model assessed the relationship between guideline-recommended initiation of therapy and total health care costs in the 6 months post-index controlling for clinical, demographic, and treatment characteristics. Logistic models for inpatient stays and emergency department visits were also evaluated. RESULTS: Guideline-recommended therapy initiation was observed in 75.5% of patients. Patients not initiating guideline-recommended therapy were older, with a mean (SD) age of 72.5 (6.7) versus 71.2 (6.2) years (P = 0.001), and more frequently identified as having a low-income subsidy (30.0% vs. 16.4%; P < 0.001). Among the 24.6% of patients who died ≤ 6 months post-index, a greater percentage had not initiated guideline-recommended therapy (28.8% vs. 23.2%; P = 0.040). In adjusted models, PS (not initiation of guideline-recommended therapy) was predictive of mortality (patients with poor PS had an 84% higher probability of death [P = 0.014]). Among decedents, 64.2% were hospitalized, and 33.9% had an oncology-related infusion within 30 days of death, with no differences by guideline-recommended initiation of therapy. These end-of-life quality indicators were not associated with guideline-recommended initiation of therapy in adjusted models. Overall, 47.5% of patients who initiated guideline-recommended therapy were hospitalized compared with 55.0% of patients who did not (P = 0.026). Patients initiating guideline-recommended therapy had higher post-index total and oncology-related health care costs and fewer hospitalizations. In models, these differences in costs and hospitalizations were not associated with initiation of guideline-recommended therapy. CONCLUSIONS: Most patients initiated guideline-recommended therapy, with no differences in mortality and quality of care at the end of life by guideline-recommended initiation of therapy, though adherence beyond treatment initiation was not assessed. Unadjusted hospitalization rates were lower and costs were higher for patients who initiated guideline-recommended therapy. These differences were no longer observed after risk adjustment, suggesting that they may have been influenced by patient characteristics, disease progression, and subsequent treatment decisions.