Learning Objectives After completing this course, the reader will be able to: Identify the most frequent errors made in KRAS testing in this study and the possible consequences for a patient. Describe factors that could increase the chance of an error during KRAS testing. This article is available for continuing medical education credit at http://CME.TheOncologist.com The use of epidermal growth factor receptor–targeting antibodies in metastatic colorectal cancer has been restricted to patients with wild‐type KRAS tumors by the European Medicines Agency since 2008, based on data showing a lack of efficacy and potential harm in patients with mutant KRAS tumors. In an effort to ensure optimal, uniform, and reliable community‐based KRAS testing throughout Europe, a KRAS external quality assessment (EQA) scheme was set up. The first large assessment round included 59 laboratories from eight different European countries. For each country, one regional scheme organizer prepared and distributed the samples for the participants of their own country. The samples included unstained sections of 10 invasive colorectal carcinomas with known KRAS mutation status. The samples were centrally validated by one of two reference laboratories. The laboratories were allowed to use their own preferred method for histological evaluation, DNA isolation, and mutation analysis. In this study, we analyze the setup of the KRAS scheme. We analyzed the advantages and disadvantages of the regional scheme organization by analyzing the outcome of genotyping results, analysis of tumor percentage, and written reports. We conclude that only 70% of laboratories correctly identified the KRAS mutational status in all samples. Both the false‐positive and false‐negative results observed negatively affect patient care. Reports of the KRAS test results often lacked essential information. We aim to further expand this program to more laboratories to provide a robust estimate of the quality of KRAS testing in Europe, and provide the basis for remedial measures and harmonization.

No abstract

No abstract

e15112 Background: To validate the Idylla MSI Test to detect microsatellite instability (MSI) in colorectal cancer (CRC) samples in comparison with Promega MSI Analysis System v1.2 (Promega MSI) and in conditions similar to normal use. Methods: The study was performed on residual formalin-fixed and paraffin-embedded (FFPE) samples obtained from routine diagnostics by two centers, University Hospital Aarhus and University Hospital Antwerp. Samples originated from CRC patients (all stages). Both centers performed the Idylla MSI Test (with 7 novel homopolymer deletion markers) at their premises on 150 and 180 samples, respectively. The comparator method, Promega MSI, was performed for all 330 samples by University Hospital Antwerp. Results: Seven (n=7) of 330 samples were excluded from the concordance analysis due to invalid or error (failed) results for Idylla MSI Test and/or Promega MSI. For the 323 valid results, overall, positive and negative percentage agreement were 99.7% (98.3%-100%;), 98.7% (92.9%-99.8%) and 100% (98.5%-100%), respectively. A higher number of invalids was observed for Promega MSI (2.1%) compared to the Idylla MSI Test (0.6%) taking into account per protocol retesting (18 retests for Promega MSI (6%) and 3 for Idylla MSI Test (1%)). Conclusions: This study validated the Idylla MSI Test with high performance and low invalid rate to discriminate MSI-H from MSS status on a clinical routine set of CRC samples.

No abstract