Germany has a long history of insufficient iodine supply and thyroid nodules occur in over 30% of the adult population, the vast majority of which are benign. Non-invasive diagnostics remain challenging, and ultrasound-based risk stratification systems are essential for selecting lesions requiring further clarification. However, no recommendation can yet be made about which system performs the best for iodine deficiency areas. In a German multicenter approach, 1211 thyroid nodules from 849 consecutive patients with cytological or histopathological results were enrolled. Scintigraphically hyperfunctioning lesions were excluded. Ultrasound features were prospectively recorded, and the resulting classifications according to five risk stratification systems were retrospectively determined. Observations determined 1022 benign and 189 malignant lesions. The diagnostic accuracies were 0.79, 0.78, 0.70, 0.82, and 0.79 for Kwak Thyroid Imaging Reporting and Data System (Kwak-TIRADS), American College of Radiology (ACR) TI-RADS, European Thyroid Association (EU)-TIRADS, Korean-TIRADS, and American Thyroid Association (ATA) Guidelines, respectively. Receiver Operating Curves revealed Areas under the Curve of 0.803, 0.795, 0.800, 0.805, and 0.801, respectively. According to the ATA Guidelines, 135 thyroid nodules (11.1%) could not be classified. Kwak-TIRADS, ACR TI-RADS, and Korean-TIRADS outperformed EU-TIRADS and ATA Guidelines and therefore can be primarily recommended for non-autonomously functioning lesions in areas with a history of iodine deficiency.

Due to the widespread use of ultrasound, small thyroid nodules (TNs) ≤ 10 mm are common findings. Standardized approaches for the risk stratification of TNs with Thyroid Imaging Reporting and Data Systems (TIRADS) were evaluated for the clinical routine. With TIRADS, the risk of malignancy in TNs is calculated by scoring the number or combination of suspicious ultrasound features, leading to recommendations for further diagnostic steps. However, there are only scarce data on the performance of TIRADS for small TNs. The aim was to compare three different TIRADS for risk stratification of small TNs in routine clinical practice. We conducted a retrospective cohort analysis of TNs ≤ 10 mm and their available histology. Nodules were classified according to three different TIRADS. In the study, 140 patients (n = 113 female) with 145 thyroid nodules (n = 76 malignant) were included. Most of the malignant nodules were papillary carcinoma (97%), and the remaining 3% were medullary carcinoma. For all tested TIRADS, the prevalence of malignancy rose with increasing category levels. The highest negative predictive value was found for ACR TI-RADS and the highest positive predictive value for Kwak-TIRADS. All tested variants of TIRADS showed comparable diagnostic performance for the risk stratification of small TNs. TIRADS seems to be a promising tool to reliably assess the risk of malignancy of small TNs.

Summary: Aim: In recent years, various professional societies published guidelines for diagnostic evaluation of thyroid nodules, in which the indication for scintigraphy is restricted to patients with subnormal TSH values. It is seen controversial whether such recommendations should be transferred to Germany, partly because of lower iodine intake in this country and the consequent higher percentage of autonomous thyroid nodules, which are not accompanied by a measurable dysfunction. Since reliable data to this topic are scarce, we analyzed multicentrically the spectrum of scintigraphically “hot” and “warm” nodules under the current epidemiological conditions. Patients, methods: In 10 German nuclear medicine out-patient institutions we evaluated the diagnostic data from a total of 514 patients, in whom unequivocally hyperfunctional nodules (focal increased uptake in comparison to perinodular tissue with a sonographically nodular correlative ≥1 cm) could be detected by 99mTcpertechnetate scintigraphy. To minimize selection bias, the surveys were not carried out in hospitals. The recorded parameters included the thyroid hormone levels, the global 99mTc-uptake (TcTU), the size of each nodule and the total autonomous nodular volume (Vaut). Results: Only 20% of the patients with “hot” nodules had subnormal TSH levels (<0.1 to 0.33 mU / l), the remaining patients had TSH levels from 0.34 to 3.5 mU /l (in one third of the patients TSH levels even exceeded 1.0 mU/l). Moreover, we found no relevant correlation between TSH and TcTU or Vaut. Conclusions: In Germany, in at far the largest proportion of patients with autonomous thyroid nodules objectified by means of scintigraphy, TSH levels are within the normal range. Since such nodules with maximum safety can be classified as benign, a corresponding scintigraphic finding has a high priority for the patient. These current data support that it is not reasonable to restrict scintigraphy to patients with subnormal TSH values in this country.

Background. Differentiated thyroid carcinoma (DTC) is characterized by an excellent prognosis with a 10-year survival rate > 90%. However, when DTC develops in a metastatic form, it has been shown to significantly impact patient survival and quality of life. Although I-131 has been shown to be an effective therapy in patients with metastatic DTC, whether its efficacy after recombinant human TSH (rhTSH) is comparable to endogenous TSH stimulation by thyroid hormone deprivation (THW) is still debated. Our present study was prompted to compare clinical results obtained in metastatic DTC by I-131 administered after rhTSH and THW stimulation protocols, respectively. Methods. A systematic search on PubMed, Web of Science, and Scopus was performed from January to February 2023. Pooled risk ratios with 95% CI were determined for evaluating the initial response after to I-131 therapy after preparation with rhTSH or THW and the disease progression. To track the accumulation of evidence and reduce type I errors because of small data, a cumulative meta-analysis was performed. A sensitivity analysis was also performed to examine the impact of individual studies on overall prevalence results. Results. Ten studies were included with a total of 1929 patients pre-treated with rhTSH (n = 953) and THW (n = 976), respectively. The cumulative data of our systematic review and meta-analysis showed an increase in the risk ratio over the years without any change in favour of a pre-treatment or the other on the effectiveness of I-131 therapy of metastatic DTC. Conclusions. Our data suggest that pretreatment with rhTSH or THW has no significant impact on the effectiveness of I-131 therapy for metastatic DTC. This implies that concerns about the use of one or the other pretreatment should be deferred to clinical evaluations made considering patient characteristics and reduction in side effects.

Background: We provide an update on calcitonin (Ctn) screening for the early detection of medullary thyroid carcinoma (MTC) and present the results of a large single-center analysis evaluating sex-specific cut-off-levels and long-term courses. Methods: A total of 12,984 consecutive adult patients (20.1% male and 79.9% female) with thyroid nodules who had undergone routine Ctn measurement were retrospectively analyzed. Patients with confirmed suspicious Ctn values were referred for surgery. Results: Ctn measurements were elevated in 207 (1.6%) patients, with values below twice the sex-specific reference limit in 82% of these cases. Further clarification was possible in 124/207 cases, of which MTC could be ruled out in 108 cases. Histopathological assessment confirmed MTC in 16/12,984 patients. Conclusions: Our extrapolated MTC prevalence of 0.14% is significantly lower than that described in early international screening studies. The stimulation test can usually be dispensable when using a decision-making concept based on sex-specific basal Ctn cut-off values. Ctn screening is recommended even in patients with very small thyroid nodules. High quality standards in pre-analytics, laboratory measurements, and the interpretation of data must be ensured, as well as close interdisciplinary cooperation between medical disciplines.

^99mTc-MIBI (MIBI) imaging is able to exclude malignancy of hypofunctioning thyroid nodules (TNs) with high probability but false positive results are frequent due to low specificity. Therefore, pre-test selection of appropriate TNs is crucial. For image evaluation visual and semiquantitative methods (Washout index, WOInd) are used. Aim of this study was to evaluate the diagnostic performance of MIBI imaging in hypofunctioning TNs with indeterminate fine-needle aspiration cytology results in a multicentric European setting. Patients with hypofunctioning TNs, EU-TIRADS 4 or 5, Bethesda III/IV and MIBI imaging were included. For visual evaluation the intensity of MIBI uptake in the TN was compared to normal thyroid tissue. 358 patients with 365 TNs (n = 68 malignant) were included. Planar imaging (SPECT) showed a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 96% (94%), 21% (22%), 22% (15%), 96% (96%), and 35% (32%). The WOInd (38.9% of all cases, optimal cutoff: −19%) showed a sens 100% (spec 89%, PPV 82%, NPV 100%, ACC 93%). For hypofunctioning TNs at intermediate or high risk with indeterminate cytology, a MIBI negative result on visual evaluation is an effective tool to rule-out thyroid malignancy. The semi-quantitative method could considerably improve overall diagnostic performance of MIBI imaging.