P3.13-03 Real-World Anaplastic Lymphoma Kinase Testing Practices: Results from a Survey in the United States

Abstract

Anaplastic lymphoma kinase (ALK) translocation is a clinically validated predictive biomarker in multiple cancer types including non-small cell lung cancer, and widespread adoption of diagnostic assays permits a review of test performance. This analysis presents ALK and epidermal growth factor receptor (EGFR) testing rates, expediency, and results from 4 large national laboratories. Deidentified data from January 2013 to December 2015 were compiled from 40 states and Washington DC and included in the final analysis. ALK status was evaluated with the Vysis ALK Break Apart FISH Probe Kit; EGFR status was evaluated by therascreen EGFR RGQ PCR Kit, cobas EGFR Mutation Test, or Sanger sequencing. Results from the most recent conclusive test were used. Collection to order (time from date of biopsy to date of biomarker test order), order to results (time from date of biomarker test order to date of available results), and overall turnaround times (collection to order + order to results) were evaluated. Results were analyzed by laboratories and US regions (Northeast, Midwest, South, and West). Data were summarized with descriptive statistics. s of 59,058 ALK and 50,992 EGFR tests were collected; 50,023 patients were tested for both ALK and EGFR, 9035 had results for ALK only, and 969 for EGFR only. Mean patient ages at ALK-positive (ALK+) and EGFR-positive (EGFR+) diagnoses were 62.5 and 69.0 years, respectively. Overall ALK+ and inconclusive rates were 2.8% and 6.5%, respectively, vs 10.4% and 6.2% for EGFR testing. ALK+ (2.3–5.1%) and inconclusive (1.1–17.4%) rates varied between test centers. In the western US, the ALK+ rate (3.3%) was comparably greater than in other regions (2.4–2.7%). The median turnaround time was 15 days, with a median of 10 days for collection to order and 4 days for order to results; some regional variation was seen in turnaround time (14–18 days). No correlation was seen between age and turnaround time. EGFR+ and ALK+ rates and age distributions were consistent with prior reports. An interesting geographic difference in ALK rates was seen that warrants further investigation. The average turnaround time was longer than current guidelines recommend, suggesting an opportunity to improve current testing practices.