ALK Testing Trends and Patterns Among Community Practices in the United States

Targeted therapy of ALK in patients with metastatic nonsquamous non-small-cell lung cancer (NSCLC) and ALK rearrangements improves outcomes compared with chemotherapy. This study assessed real-world ALK testing patterns among community practices in the United States in patients with advanced (stage IIIB or IV) NSCLC.

Patients age ≥ 18 years with two or more visits within the Flatiron Health electronic health record-derived database after January 2011 and diagnosed with stage IIIB or IV NSCLC through May 2017 were included in this analysis. Logistic regression was used to examine the association between demographic and clinical characteristics and testing for ALK rearrangements.

Of 31,483 patients analyzed from the database, 16,726 patients (53.1%) were tested for ALK rearrangements. ALK testing rates were 66.9% and 18.5% in patients with nonsquamous and squamous histology, respectively. Average ALK testing rates increased over time from 32.4% in 2011 to 62.1% in 2016. Fluorescent in situ hybridization was the most common ALK testing method. Agreement between fluorescent in situ hybridization and other assays ranged from 94.1% to 97.9%. Median (interquartile range) time from laboratory receipt of sample to first ALK test result was 7 (7) days; median time from advanced diagnosis to first ALK test result was 25 (29) days. Patients who were older, male, had a history of smoking, lived in non-Western US regions, and who had recurrent disease or squamous histology were less likely to be tested for ALK. Patients with Medicaid and Medicare insurance were less likely to be tested than patients with commercial insurance. Overall, 21.5% of patients initiated therapy (20.4% chemotherapy) before receiving test results.

ALK testing rates have increased over time. However, certain subgroups of patients are less likely to be tested, suggesting that additional education on molecular testing is warranted.