EGFR mutation testing and TKI treatment patterns among veterans with stage III and IV non-small cell lung cancer

Abstract

Background: Epidermal growth factor receptor (EGFR) mutation testing is recommended in metastatic non-small cell lung cancer (NSCLC). The objective of this study was to assess changes in EGFR mutation testing patterns and tyrosine kinase inhibitor (TKI) use in US veterans with stage III-IV NSCLC between 2013 and 2017.

Patients and methods: Retrospective study using linked data from Department of Veterans Affairs (VA) Cancer Registry System, Corporate Data Warehouse, commercial laboratories, and clinical notes. Generalized linear mixed models accounting for clustering by VA facility were used to determine factors associated with EGFR mutation testing.

Results: From 2013 to 2017, EGFR mutation testing increased from 29.5% to 38.4% among veterans with stage III-IV NSCLC and from 47.0% to 57.4% among veterans with stage IV non-squamous disease. Factors associated with increased odds of testing included being married, Medicare enrollment, and adenocarcinoma histology. Factors associated with decreased odds of testing included Medicaid eligibility, stage III disease, increasing age, being a current or former smoker, increasing Charlson-Deyo comorbidity score, and receiving cancer care in the South. Appropriate use of a TKI rose from 2013 to 2017 (17.2% to 74.1%).

Conclusion: EGFR mutation testing rates increased to almost 60% in the stage IV non-squamous NSCLC population in 2017, with residual opportunity for further increase. Several sociodemographic characteristics, comorbidities, and geographic regions were associated with EGFR mutation testing suggestive of inequitable testing decisions. Appropriate use of TKI improved drastically from 2013 to 2017 demonstrating rapidly changing practice patterns through the adoption phase of new treatment options.

Keywords: Cancer genomics; Targeted drug therapy.