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Introduction: The treatment approach for recently diagnosed advanced non-small cell lung cancer (NSCLC) with EGFR mutations primarily relies on confirming the tissue diagnosis as non-squamous NSCLC. This routine clinical practice of tissue diagnosis imposes several barriers and delays in turnaround time (TAT) for biomarker testing, significantly delaying the time to treatment. The objective of this study is to investigate the 'plasma first' approach for detection of EGFR mutation in advanced stage treatment naïve NSCLC patients., Methods: We prospectively collected blood samples of treatment naïve patients with clinical and radiological suspicion of advanced stage NSCLC prior to obtaining tissue biopsy. Plasma cfDNA was tested for EGFR mutation using two different methods. We compared the sensitivity and TAT of liquid biopsy with tissue biopsy., Results: In total, we analyzed plasma cell-free DNA (cfDNA) of 236 patients suspected of having advanced NSCLC for EGFR mutations. We observed a notably shorter turnaround time (TAT) of 3 days, which was significantly quicker compared to the 12-day TAT for tissue biopsy (p < 0.05). The ddPCR method had a sensitivity of 82.8%, which was higher than 66.34% sensitivity of ARMS-PCR. The current study also highlights that there is no significant difference in the clinical outcome of the patients whether treated based on liquid biopsy only or tissue biopsy (median progression-free survival of 11.56 vs. 11.9 months; p = 0.94)., Conclusions: Utilizing a 'plasma first' strategy, given its shorter turnaround time, strong positive concordance and comparable outcomes to tissue biopsy, emerges as a highly specific and reliable method for detecting EGFR mutations in advanced-stage NSCLC., (© 2024. The Author(s).)

Introduction: DNA extracted from malignant pleural effusion (PE) sediments is the traditional source of tumor DNA for predictive biomarker molecular testing (MT). Few recent studies have proposed the utility of cell-free DNA (cfDNA) extracted from effusion cytology centrifuged supernatants (CCS) in MT. The aim of this study was to assess the feasibility and utility of molecular testing on cfDNA extracted from PE CCS in lung cancer patients., Materials and Methods: The study was of prospective design. All PE CCS were collected and stored. Subsequently, in patients confirmed as primary lung adenocarcinoma (LUAD) and where patient matched effusion sediment/tissue biopsy/plasma was being tested for EGFR mutations, cfDNA extraction and EGFR MT by real-time polymerase chain reaction (qPCR) were performed. Custom panel targeted next-generation sequencing (NGS) (Ion Torrent; Thermo Fisher, Carlsbad, CA) was also performed wherever feasible., Results: Out of 299 PE CCS collected, 20 CCS samples were included in the study. Concordant EGFR mutations were detected in pleural effusion CCS of 10 of 11 (91%) EGFR mutant cases as per qPCR performed on the matched sediment DNA (n = 8), lung biopsy (n = 2), and plasma (n = 1) samples. In 1 positive sample, CCS detected additional EGFR T790M mutation. Among 10 CCS samples also tested by NGS, additional EGFR mutations missed by qPCR were picked up in 2 (2 of 10). Success of mutation detection in CCS cfDNA did not correlate with cfDNA quantity or tumor fraction in sediment., Conclusions: cfDNA from effusion CCS is a reliable and independent source of tumor DNA highly amenable for MT and complement results from other tumor DNA sources for comprehensive mutation profiling in LUAD patients., (Copyright © 2024 American Society of Cytopathology. Published by Elsevier Inc. All rights reserved.)