Thyroid nodular disease is common, but predicting the risk of malignancy can be difficult. In this prospective study, we aimed to assess the diagnostic accuracy of shear wave elastography (SWE) in predicting thyroid malignancy. Patients with thyroid nodules were enrolled from a surgical tertiary unit. Elasticity index (EI) measured by SWE was registered for seven EI outcomes assessing nodular stiffness and heterogeneity. The diagnosis was determined histologically. In total, 329 patients (mean age: 55 ± 13 years) with 413 thyroid nodules (mean size: 32 ± 13 mm, 88 malignant) were enrolled. Values of SWE region of interest (ROI) for malignant and benign nodules were highly overlapping (ranges for SWE-ROImean: malignant 3–100 kPa; benign 4–182 kPa), and no difference between malignant and benign nodules was found for any other EI outcome investigated (P = 0.13–0.96). There was no association between EI and the histological diagnosis by receiver operating characteristics analysis (area under the curve: 0.51–0.56). Consequently, defining a cut-off point of EI for the prediction of malignancy was not clinically meaningful. Testing our data on previously proposed cut-off points revealed a low accuracy of SWE (56–80%). By regression analysis, factors affecting EI included nodule size >30 mm, heterogeneous echogenicity, micro- or macrocalcifications and solitary nodule. In conclusion, EI, measured by SWE, showed huge overlap between malignant and benign nodules, and low diagnostic accuracy in the prediction of thyroid malignancy. Our study supports that firmness of thyroid nodules, as assessed by SWE, should not be a key feature in the evaluation of such lesions.
Kristine Zøylner Swan, Steen Joop Bonnema, Marie Louise Jespersen, and Viveque Egsgaard Nielsen
Selma Flora Nordqvist, Victor Brun Boesen, Åse Krogh Rasmussen, Ulla Feldt-Rasmussen, Laszlo Hegedüs, Steen Joop Bonnema, Per Karkov Cramon, Torquil Watt, Mogens Groenvold, and Jakob Bue Bjorner
Objective: ThyPRO is the standard thyroid patient-reported outcome (PRO). The change in scores that patients perceive as important remains to be ascertained. The purpose of this study was to determine values for minimal important change (MIC) for ThyPRO.
Methods: A total of 435 patients treated for benign thyroid diseases completed ThyPRO at baseline and 6 weeks following treatment initiation. At 6-weeks follow-up, patients also completed Global Rating of Change items. For each 0-100 scale, two MIC values were identified: an MIC for groups, using the ROC curve method and an MIC for individual patients, using the reliable change Index.
Results: ROC analyses provided group-MIC estimates of 6.3 to 14.3 (score range 0-100). Evaluation of area under the curve (AUC) supported the robustness for 9 of 14 scales (AUC > 0.7). Reliable change index estimates of individual-MIC were 8.0 to 21.1. For all scales but two, the individual-MIC values were larger than the group-MIC values.
Conclusions: Interpretability of ThyPRO was improved by the establishment of MIC values, which was 6.3 to 14.3 for groups and 8.0 to 21.1 for individuals. Thus, estimates of which changes are clinically relevant, are now available for future studies. We recommend using MIC values found by ROC analyses to evaluate changes in groups of patients, whereas MIC values identified by a dual criterion, including the reliability of changes, should be used for individual patients, e.g. to identify individual responders in clinical studies or practice.