Complementing Tissue Testing With Plasma Mutation Profiling Improves Therapeutic Decision-Making for Patients With Lung Cancer.

Yukti Choudhury,Jamie Mong,Augustine Tee,Kao Chin Ngeow,Min-Han Tan,Ruth Rosalyn Goh,Jonathan Poh,Jun Li Shi

doi:10.3389/fmed.2022.758464

Abstract

BackgroundTissue biopsy is an integral part of the diagnostic approach to lung cancer. It is however invasive and limited by heterogeneity. Liquid biopsies may complement tissue testing by providing additional molecular information and may be particularly helpful in patients from whom obtaining sufficient tissue for genomic profiling is challenging.MethodsPatients with suspected lung cancer (n = 71) were prospectively recruited. Blood and diagnostic tissue samples were collected within 48 h of each other. Plasma cell-free DNA (cfDNA) testing was done using an ultrasensitive amplicon-based next-generation sequencing (NGS) panel (plasma NGS testing). For cases diagnosed as non-small cell lung carcinoma (NSCLC) via histology or cytology, targeted testing for epidermal growth factor receptor (EGFR) mutations was performed using tissue biopsy samples (tissue EGFR testing), where available. Concordance of clinically actionable mutations between methods and sample types was assessed.ResultsFor confirmed NSCLC cases (n = 54), tissue EGFR test results were available only for 70.3% (38/54) due to sample inadequacies, compared to blood samples for 98.1% (53/54) cases. Tissue EGFR testing identified sensitizing EGFR (L858R or exon 19 deletion) mutation in 31.6% (12/38) of cases. Plasma NGS identified clinically actionable mutations in 37.7% (20/53) of cases, including EGFR mutations in two cases with no tissue EGFR results, and mutations in KRAS, BRAF, and MET. The overall sensitivity of sensitizing EGFR mutation detection by plasma NGS was 75% (9/12), and specificity was 100% (25/25) in patients tested in both tissue EGFR and plasma NGS (n = 37). In this cohort of patients, tissue EGFR testing alone informed clinical decisions in 22.2% (12/54) of cases. Adding plasma NGS to tissue EGFR testing increased the detection rate of actionable mutations to 42.6% (23/54), representing a 1.9-fold increase in clinically relevant findings. The average turnaround time of plasma NGS was shorter than standard tissue testing (10 vs. 29.9 days, p < 0.05).ConclusionsIn the first-line setting, plasma NGS was highly concordant with tissue EGFR testing. Plasma NGS increases the detection of actionable findings with a shorter time to results. This study outlines the clinical utility of complementary plasma mutation profiling in the routine management of lung cancer patients.

Highlights

Lung cancer is the most common cause of cancer death worldwide and nonsmall cell lung cancer (NSCLC) accounts for 85% of all the lung cancers, making NSCLC a major cause of mortality [1]
Molecular diagnostic testing combined with molecular targeted agents directed against driver mutations in EGFR, ALK, ROS1, BRAF, MET, RET, and most recently KRAS has significantly improved the outcomes for patients with advanced disease harboring these alterations [6, 7]
This study focuses on standard tissue testing for mutations in the EGFR gene, which is mutated in 40–60% of Asian patients and 10–20% of Caucasian patients with NSCLC [22]

Summary

Introduction

Lung cancer is the most common cause of cancer death worldwide and nonsmall cell lung cancer (NSCLC) accounts for 85% of all the lung cancers, making NSCLC a major cause of mortality [1]. Major progress has been made in the treatment of advanced NSCLC with the identification of specific driver mutations and the development of targeted therapies [3, 4]. Molecular diagnostic testing combined with molecular targeted agents directed against driver mutations in EGFR, ALK, ROS1, BRAF, MET, RET, and most recently KRAS has significantly improved the outcomes for patients with advanced disease harboring these alterations [6, 7]. The most recent National Comprehensive Cancer Network (NCCN) guideline recommendations (Version 5.2021) for the management of NSCLC include testing for EGFR, BRAF, ALK, ROS1, RET, KRAS, MET exon 14 skipping, and NTRK in nonsquamous lung cancer, as part of broader molecular profiling [8]. Tissue biopsy is an integral part of the diagnostic approach to lung cancer. Liquid biopsies may complement tissue testing by providing additional molecular information and may be helpful in patients from whom obtaining sufficient tissue for genomic profiling is challenging

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