Expert opinion on NSCLC small specimen biomarker testing - Part 2: Analysis, reporting, and quality assessment

Abstract

The diagnostic work-up for non-small cell lung cancer (NSCLC) requires biomarker testing to guide therapy choices. This article is the second of a two-part series. In Part 1, we summarised evidence-based recommendations for obtaining and processing small specimen samples (i.e. pre-analytical steps) from patients with advanced NSCLC. Here, in Part 2, we summarise evidence-based recommendations relating to analytical steps of biomarker testing (and associated reporting and quality assessment) of small specimen samples in NSCLC. As the number of biomarkers for actionable (genetic) targets and approved targeted therapies continues to increase, simultaneous testing of multiple actionable oncogenic drivers using next-generation sequencing (NGS) becomes imperative, as set forth in European Society for Medical Oncology guidelines. This is particularly relevant in advanced NSCLC, where tissue specimens are typically limited and NGS may help avoid tissue exhaustion compared with sequential biomarker testing. Despite guideline recommendations, significant discrepancies in access to NGS persist across Europe, primarily due to reimbursement constraints. The use of increasingly complex testing methods also has implications for the reporting of results. Molecular testing reports should include clinical interpretation with additional commentary on sample adequacy as appropriate. Molecular tumour boards are recommended to facilitate the interpretation of complex genetic information arising from NGS, and to collaboratively determine the optimal treatment for patients with NSCLC. Finally, whichever testing modality is employed, it is essential that adequate internal and external validation and quality control measures are implemented.

Keywords: Best practice; External quality assessment; Liquid biopsy; Molecular diagnostics; Next-generation sequencing; Non-small cell lung carcinoma.

Fig. 1

Summary of recommendations from international guidelines for a approved and b emerging biomarkers [8, 57]. Figure adapted from Kerr et al. [8]. Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved. Reproduced under the terms of Creative Commons Attribution 4.0 International (CC BY 4.0) license. ^aNCCN Clinical Practice Guidelines In Oncology (NCCN Guidelines^®) for NSCLC provide recommendations for certain individual biomarkers that should be tested and recommend testing techniques but do not endorse any specific commercially available biomarker assays or commercial laboratories, ^bbiomarker testing for KRAS and RET is recommended in the NCCN Guidelines^®, ^cthe NCCN Guidelines^® do not recommend TMB testing. ALK anaplastic lymphoma kinase, AMP Association for Molecular Pathology, ASCO American Society of Clinical Oncology, BRAF B-Raf proto-oncogene, CAP College of American Pathologists, EGFR epidermal growth factor receptor, ERBB2 Erb-B2 receptor tyrosine kinase 2, ESMO European Society for Medical Oncology, HER2 human epidermal growth factor receptor 2, IASLC International Association for the Study of Lung Cancer, IHC immunohistochemistry, KRAS Kirsten rat sarcoma viral oncogene homolog, MET hepatocyte growth factor receptor, NCCN National Comprehensive Cancer Network, NTRK neurotrophic tyrosine receptor kinase, PD-L1 programmed cell death ligand 1, RET rearranged during transfection, ROS1 ROS proto-oncogene 1, TMB tumour mutational burden

Fig. 2

Summary of country-specific guidelines for biomarker testing of advanced or recurrent NSCLC [8]. Figure adapted from Kerr et al. [8]. Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved. Reproduced under the terms of Creative Commons Attribution 4.0 International (CC BY 4.0) license. ALK anaplastic lymphoma kinase, BRAF B-Raf proto-oncogene, EGFR epidermal growth factor receptor, ERBB2 Erb-B2 receptor tyrosine kinase 2, HER2 human epidermal growth factor receptor 2, KRAS Kirsten rat sarcoma viral oncogene homolog, MET hepatocyte growth factor receptor, NGS next-generation sequencing, NRG1 neuregulin-1, NSCLC non-small cell lung cancer, NTRK neurotrophic tyrosine receptor kinase, O optional, P preferred, PD-L1 programmed cell death ligand 1, RET rearranged during transfection, ROS1 ROS proto-oncogene 1, TMB tumour mutational burden. ^aNTRK is also test-approved in limited circumstances; in England, some targeted therapies for other biomarkers may be available through the Cancer Drugs Fund. ^bConsider other molecular tests, depending on clinic or drug availability. ^cNTRK, KRAS, MET, RET, and ERBB2/HER2 will be included in the current revision. ^dThe use of these biomarkers as individual tests is currently not indicated; instead, it is advised to include them in extended panels performed either initially in all advanced NSCLCs or when previous EGFR/ALK/ROS1/BRAF testing is negative. ^eLiquid biopsy testing is recommended if the patient cannot undergo biopsy or if tissue molecular analysis results are uninformative. ^fLiquid biopsy for EGFR assessment only when tissue biopsy is not available. ^gOn-demand testing for cases not fulfilling the reflex criteria (e.g. for squamous carcinomas with some suggestive clinical features [young age, non-smoker, etc.])

Fig. 3

Diagnostic algorithm for liquid biopsy use in advanced/metastatic NSCLC (updated IASLC consensus statement) [34]. Figure reproduced from [34], J Thorac Oncol, Vol. 16, Rolfo C, et al., Liquid Biopsy for Advanced NSCLC: A Consensus Statement From the International Association for the Study of Lung Cancer, pages 1647–1622. Copyright (2021), with permission from J Thorac Oncol. Published by Elsevier Ltd. All rights reserved. Sequential approach: tissue followed by cfDNA complementary approach, concurrent tissue and cfDNA, plasma first approach, cfDNA first. cfDNA cell-free DNA, IASLC International Association for the Study of Lung Cancer, NSCLC non-small cell lung cancer

Fig. 4

Error rates in lung cancer biomarker analysis for EGFR, ALK, and ROS1 across EQA schemes run by the European Society of Pathology, 2012–2015 [58]. Figure adapted from Keppens et al. [58]. Copyright © 2021 The Authors. Published by Impact Journals. All rights reserved. Reproduced under the terms of Creative Commons Attribution 3.0 International (CC BY 3.0) license. ALK anaplastic lymphoma kinase, EGFR epidermal growth factor receptor, EQA external quality assessment, FISH fluorescent in situ hybridisation, IHC immunohistochemistry, ROS1 ROS proto-oncogene 1