472 chapter 12 procedures) or IV diagnosis was established by blinded central review by two dedicated thyroid pathologists. None of the patients underwent MD before trial inclusion. Next, all patients underwent one [18F]FDG-PET/CT of the neck using a standard acquisition and reconstruction protocol in accordance with the European Association of Nuclear Medicine (EANM) guidelines (Supplementary Table 1)[468, 469]. Two independent, blinded, experienced nuclear medicine physicians visually assessed all scans. An [18F]FDG positive index nodule was defined as any focal [18F]FDG uptake in the thyroid that corresponded to the index nodule in location and size and that was visually higher than the background uptake in the surrounding normal thyroid. The maximum standardized uptake value (SUVmax) was additionally measured to support the visual interpretation. When visually [ 18F] FDG negative, patients allocated to the [18F]FDG-PET/CT-driven investigational arm were advised active surveillance of the nodule. All other patients, i.e., those with an [18F]FDG positive index nodule and/or all patients allocated to the control arm, were advised to undergo diagnostic surgery. All postoperative management was based on the local histopathological diagnosis and current guidelines [17, 467]. In the current study, we performed a pre-planned elaborative analysis of the trial data, comprising additional MD and encompassing the whole trial cohort. The research was completed in accordance with the Declaration of Helsinki as revised in 2013. The trial protocol was approved by the IRB, the Medical Research Ethics Committee on Research Involving Human Subjects region ArnhemNijmegen, Nijmegen, the Netherlands, on 10 November 2014 (Ethics board approval number: 20141205). All trial participants gave their written informed consent prior to any study procedures. Molecular analysis For MD, total nucleic acid (DNA and RNA) was isolated from tumour cells scraped off cytology slides or from micro-dissected cytology cell blocks [684-686]. Next-generation sequencing (NGS) was performed on the Ion Torrent GeneStudio™ S5 platform at the ISO15189 accredited Molecular Diagnostics Unit of the Pathology department of the Leiden University Medical Centre (Leiden, The Netherlands) using custom NGS panels for somatic mutation analysis, gene fusion analysis, and CNA and loss of heterozygosity (LOH) analysis. As previously described, the custom Ampliseq™ Cancer Hotspot v6 panel (Thermo Fisher Scientific, Waltham, MA, USA), which targets 87 genes that are relevant for the characterization of thyroid neoplasms, and the Archer® FusionPlex CTL v2 panel (ArcherDX Inc., Boulder, CO, USA), which assesses 19 relevant genes, were used for somatic mutation and gene fusion analysis, respectively (details provided in the Supplementary Data) [525, 684-686]. CNA-LOH analysis was performed using the custom AmpliSeq™ NGS genomewide LOH v2 panel, which assesses LOH and other chromosomal imbalances using 1,500 SNPs, evenly distributed across all autosomes and the X chromosome. Dependent on the cytological classification, the three NGS panels were applied according to a predefined flowchart (Figure 1). To save valuable resources, application was stepwise in nodules with non-oncocytic cytology: somatic
RkJQdWJsaXNoZXIy MTk4NDMw