Molecular analysis of circulating tumour DNA (ctDNA) is becoming increasingly important in clinical treatment decisions. A pilot External Quality Assessment (EQA) scheme for ctDNA analysis was organized by four European EQA providers under the umbrella organization IQN Path, in order to investigate the feasibility of delivering an EQA to assess the detection of clinically relevant variants in plasma circulating cell-free DNA (cfDNA) and to analyze reporting formats. Thirty-two experienced laboratories received 5 samples for EGFR mutation analysis and/or 5 samples for KRAS and NRAS mutation analysis. Samples were artificially manufactured to contain 3 mL of human plasma with 20 ng/mL of fragmented ctDNA and variants at allelic frequencies of 1 and 5%. The scheme error rate was 20.1%. Higher error rates were observed for RAS testing when compared to EGFR analysis, for allelic frequencies of 1% compared to 5%, and for cases including 2 different variants. The reports over-interpreted wild-type results and frequently failed to comment on the amount of cfDNA extracted. The pilot scheme demonstrated the feasibility of delivering a ctDNA EQA scheme and the need for such a scheme due to high error rates in detecting low frequency clinically relevant variants. Recommendations to improve reporting of cfDNA are provided.

Liquid biopsy testing is a new laboratory-based method that detects tumour mutations in circulating free DNA (cfDNA) derived from minimally invasive blood sampling techniques. Recognising the significance for clinical testing, in 2017, IQN Path provided external quality assessment for liquid biopsy testing. Representatives of those participating laboratories were invited to attend a workshop to discuss the findings and how to achieve quality implementation of cfDNA testing in the clinical setting, the discussion and outcomes of this consensus meeting are described below. Predictive molecular profiling using tumour tissue in order to select cancer patients eligible for targeted therapy is now routine in diagnostic pathology. If insufficient tumour tissue material is available, in some circumstances, recent European Medicines Agency (EMA) guidance recommends mutation testing with plasma cfDNA. Clinical applications of cfDNA include treatment selection based on clinically relevant mutations derived from pre-treatment samples and the detection of resistant mutations upon progression of the disease. In order to identify tumour-related mutations in amongst other nucleic acid material found in plasma samples, highly sensitive laboratory methods are needed. In the workshop, we discussed the variable approaches taken with regard to cfDNA extraction methods, the tests, and considered the impact of false-negative test results. We explored the lack of standardisation of complex testing procedures ranging from plasma collection, transport, processing and storage, cfDNA extraction, and mutation analysis, to interpretation and reporting of results. We will also address the current status of clinical validation and clinical utility, and its use in current diagnosis. This workshop revealed a need for guidelines on with standardised procedures for clinical cfDNA testing and reporting, and a requirement for cfDNA-based external quality assessment programs.

In personalized medicine, predictive biomarker testing is the basis for an appropriate choice of therapy for patients with cancer. An important tool for laboratories to ensure accurate results is participation in external quality assurance (EQA) programs. Several providers offer predictive EQA programs for different cancer types, test methods, and sample types. In 2013, a guideline was published on the requirements for organizing high-quality EQA programs in molecular pathology. Now, after six years, steps were taken to further harmonize these EQA programs as an initiative by IQNPath ABSL, an umbrella organization founded by various EQA providers. This revision is based on current knowledge, adds recommendations for programs developed for predictive biomarkers by in situ methodologies (immunohistochemistry and in situ hybridization), and emphasized transparency and an evidence-based approach. In addition, this updated version also has the aim to give an overview of current practices from various EQA providers.

A stitch in time saves nine: external quality assessment rounds demonstrate improved quality of biomarker analysis in lung cancer A stitch in time saves nine: external quality assessment rounds demonstrate improved quality of biomarker analysis in lung cancer

Predictive biomarkers allow clinicians to optimise cancer treatment decisions. Therefore, molecular biomarker test results need to be accurate and swiftly available. To ensure quality of oncology biomarker testing, external quality assessments (EQA) for somatic variant analyses were organised. This study hypothesised whether laboratory characteristics influence the performance of laboratories and whether these can be imposed before authorisation of biomarker testing. Longitudinal EQA data from the European Society of Pathology were available over six (metastatic colorectal cancer) and four years (non-small cell lung cancer), including the percentage of analysis errors and technical failures, and information on laboratory characteristics (accreditation status, laboratory setting, number of samples analysed and detection method). Statistical models for repeated measurements were used to analyse the association between the EQA results and the laboratory characteristics. Laboratory accreditation was associated with fewer analysis errors in early stages of biomarker introduction into the laboratory. Analysing more samples, or university and research laboratories showed better performance. Changing the detection method did not have an effect. The indicators support the clinicians in choosing molecular pathology laboratories by improving quality assurance and guaranteeing patient safety. Accreditation of laboratories, centralisation of biomarker testing or a university and research setting should be stimulated.