24 chapter 2 surgical risks. In the case of malignant lesions, a second-stage completion thyroidectomy is often indicated, which is associated with additional costs and higher risks of surgical complications [5356]. An additional preoperative test or combination of tests for thyroid nodules with indeterminate cytology should prevent unbeneficial diagnostic hemithyroidectomies for benign nodules, limit the number of two-stage surgeries for thyroid malignancies, or both. With rapidly advancing technology, the possibilities for additional diagnostic techniques seem endless: the applications of existing diagnostics such as ultrasound, PET/CT and immunocytochemistry are extended and more clearly demarcated for use in indeterminate thyroid nodules. High-tech molecular tests such as gene mutation panels, gene or microRNA expression profiles and sequencing techniques are hot-topic [44, 57-61]. Every currently known engagement point from the genotype to the phenotype of the tumour is being explored. Combined, the various research fields encompass an extensive range of investigative methods. Individually they usually focus on one or two methods only, making one-to-one comparison of these diagnostics difficult. The 2015 American Thyroid Association (ATA) guidelines suggested several additional tests, but a definitive answer or complete overview of all available tests is still lacking [17]. Alongside higher-level expert discussions and lobbying of med tech companies, clinical endocrinologists and thyroid surgeons ponder about the best solution for their individual patients. Their choices depend on the characteristics of their patient populations, availability and costs of a certain test, and personal preference. In any case, a useful additional test should be accurate, accessible, affordable and affect patient management. This review aims to provide practical considerations for physicians involved in the management of patients with thyroid nodules. It gives an overview of the available literature on additional diagnostic tests for thyroid nodules with indeterminate cytology. We will work our way down from genotype to phenotype, discussing both anatomical and functional techniques, from the state-of-the-art molecular and imaging biomarkers as well as widely available conventional imaging techniques. The ability of a test to distinguish between malignant and benign nodules in a preoperative setting is discussed, focusing on clinical validation and utility, and including the development phase, costeffectiveness and availability of each technique, where appropriate. Table 2 provides a summarized overview of the discussed diagnostics and their main attributes.
RkJQdWJsaXNoZXIy MTk4NDMw