RESUMO
PURPOSE: Genomic analysis of plasma cell-free DNA has become a widespread tool for advanced non-small-cell lung cancer care. Whereas accuracy has been reported on widely, its usefulness is also tied tightly to its turnaround time (TAT), which is not well studied. METHODS: We studied the TAT of commercial plasma next-generation sequencing (NGS; Guardant360) for 533 results from 461 patients at our center between August 2016 and October 2019. The study received institutional review board approval as a quality improvement study; therefore, the results of the test and clinical setting were not analyzed. RESULTS: TAT from blood draw to result (median of 9 days) was slightly longer than the TAT from laboratory receipt to result, a median of 7 days. Testing volume at our center increased three-fold over the time of the study. During this period, clinical TAT decreased from an initial median of 12 days to a median of 8 days in 2018, but more recently the median increased slightly to 9 days. During the most recent 12 months, 231 (95%) of 247 cases resulted within 14 days from blood draw, with delayed results usually because of billing, whereas 44 cases (18%) resulted within 7 days of blood draw. Studying 92 cases drawn in the most recent 3-month period, the median time of result receipt was 4:01 pm Eastern Time/1:01 pm Pacific Time; 39 results (43%) were returned after 5:00 pm Eastern Time. CONCLUSION: In a large single-institution experience, we find that plasma NGS results can routinely be expected within 2 weeks, but uncommonly result within 1 week, supporting the need for new strategies to incorporate plasma NGS into the initial genotyping of advanced non-small-cell lung cancer.
