General discussion 497 13 To the best of our knowledge, the EfFECTS trial provided the highest level of evidence on the matter for the first time, thereby creating highly valuable results for clinical practice and future research, but also encountering important learning points. In addition to the topics that have already been discussed in the individual preceding chapters of this thesis, the current chapter will discuss some of the remaining challenges in the optimization of the diagnosis of indeterminate thyroid nodules. This comprises the current thyroid guidelines and their progressive insights, and the current and future challenges in clinical practice and research, including important considerations for future research that emerged during the execution of the EfFECTS trial and the writing of this thesis. Current guidelines and progressive insights The current national and international guidelines make varying recommendations for additional diagnostics in the workup of indeterminate thyroid nodules. In the following sections, we will discuss the position of [18F]FDG-PET/CT and MD in the current Dutch, American Thyroid Association (ATA), European Thyroid Association (ETA), and French guidelines, taking into account the year of publication of the respective guideline and progressive insights in the field. In the current Dutch thyroid guidelines, which were published in 2014, the diagnostic potential of [18F]FDG-PET/CT is discussed based on the evidence of the 2011 meta-analysis by Vriens et al. [38, 467]. Based on expert opinion, our national guidelines advised that [18F]FDG-PET/CT may be considered in patients who prefer to refrain from diagnostic surgery. Selective application of MD is recommended, provided that it may change the course of management, with a side note that MD on FNAC samples is mainly still in the future [467]. In the current 2015 ATA guidelines, a striking statement was made regarding the accuracy requirements of additional testing for thyroid nodules. Even though it was nearly written in the guidelines’ margins, this advice has since been widely adopted in diagnostic studies. It stated that an ideal rule-in test for thyroid malignancy would have a positive predictive value (PPV) similar to a malignant cytological diagnosis (i.e., 97%) and an ideal rule-out test would have a negative predictive value (NPV) similar to a benign cytological diagnosis (i.e., 96%) [17, 23]. These PPVs and NPVs should be precise and reproducible [17]. Although its diagnostic potential in indeterminate thyroid nodules was acknowledged based on, among other things, the previous meta-analysis from our research group [38], [18F]FDG-PET/CT was not routinely recommended in the current ATA guidelines as higher level evidence was lacking:
RkJQdWJsaXNoZXIy MTk4NDMw