Molecular testing in advanced lung adenocarcinoma: A single-center experience.

Abstract

e21157 Background: Standard of care testing prior to first-line therapy for advanced lung non-small cell lung cancer (NSCLC) includes EGFR mutations, ALK rearrangements, and PD-L1 expression. There is limited real-world evidence on NSCLC molecular testing patterns in underrepresented racial and ethnic populations. Methods: We identified adult patients newly diagnosed with stage IV lung adenocarcinoma at the University of Illinois Hospital & Health Sciences System between January 1, 2015 and October 1, 2019. Rates of biomarker testing for EGFR, ALK, and PD-L1 were determined, as well as the median time from tissue biopsy to each result. Data were stratified by race and ethnicity. Timelines of molecular testing were studied in relation to cancer therapy initiation. Results: Among 80 patients diagnosed with advanced NSCLC, 70 (87.5%) received EGFR testing, 69 (86.3%) received ALK testing, and 40 (50%) received PD-L1 testing from 2015-2019. Thirty-one (81.6%) patients diagnosed from 2017-2019 had PD-L1 testing. Median time from biopsy to molecular test result in the overall population was 3.0 weeks for EGFR, 3.0 weeks for ALK, and 2.0 weeks for PD-L1. There was no significant difference in EGFR and ALK testing rates between Black and non-Black patients. PD-L1 testing was decreased in Black patients compared to non-Black patients ( p = 0.02) from 2015-2019, but there was no significant difference from 2017-2019. All three biomarkers had similar testing rates between White and non-White patients and between Hispanic and non-Hispanic patients. Median time from biopsy to PD-L1 result decreased from over 12 weeks in 2015 and 2016 to 2 weeks in 2018 and 2019. Six (7.5%) patients received first-line treatment before results were available. Two (2.5%) required treatment changes based on results. Conclusions: In an urban, academic center we found similar EGFR and ALK testing rates among race and ethnicity subgroups. PD-L1 testing was lower in Black patients from 2015-2019 but not after national guidelines recommended PD-L1 testing in 2017. Treatment was initiated without full biomarker data in multiple cases, sometimes leading to changes in therapy after results were obtained. Further studies are indicated to determine strategies for comprehensive, timely, and equitable biomarker testing in advanced NSCLC.[Table: see text]