Poor Sensitivity and Specificity
A CME article published in Deutsches Ärzteblatt gives rise to the expectation that it reflects confirmed results. The article by Führer et al. clearly does not meet this expectation. The authors postulate that in every case of a thyroid nodule, scintigraphy should be undertaken at least once. The sensitivity and specificity of this investigation are poor with regard to malignancies (2, 3). It is easy to form an impression of unjustifiably excessive diagnostic testing (seeing that the material that is mass-handled is radioactive). The recommendation to measure calcitonin in every patient with nodular goiter is controversial, to say the least. This recommendation may be appropriate for specialist endocrinology outpatient clinics. For general practice, with its low incidence of thyroid malignancies, it is definitely excessive. The recommendation to measure thyroid antibodies is not sufficiently supported—especially with regard to the relevance of the result for subsequent clinical action. The authors finally recommend a combination of iodine and L-thyroxine. The LISA study cited by the authors (4) investigated iodine and L-thyroxin in isolation as well as in combination. The treated nodules were 1.47–1.96 mL in size. The relative reduction in size by 17.3% therefore corresponded to an absolute reduction of 0.25–0.33 mL—a completely irrelevant order of magnitude. The thyroid volume of 18.2–18.8mL decreased by 1.5 mL, which is similarly irrelevant.
Clinically relevant end points, such as frequency of thyroidectomies or development of thyrotoxicosis, were not studied. The recommendation given in the article is not supported by this study. To publish a CME article full of unconfirmed, not evidence-based, recommendations for maximum diagnostic testing and treatment as a CME article in Deutsches Ärzteblatt suggests, in my opinion unjustifiably, that the authors are describing the current gold standard.
Dr. med. Günther Egidi
Arzt für Allgemeinmedizin, Bremen, email@example.com
Conflict of interest statement
The author declares that no conflict of interest exists.
|1.||Führer D, Bockisch A, Schmid KW: Euthyroid goiter with and without nodules—diagnosis and treatment. Dtsch Arztebl Int 2012; 109(29–30): 506–16. VOLLTEXT|
|2.||Procopiou M: Wann und wie muss ein Schilddrüsenknoten abgeklärt werden? Therapeutische Umschau 2011; 68: 285–9. MEDLINE|
|3.||Cronan J: Thyroid Nodules. Is it time to turn off the US machines? Radiology 2008; 247: 602–4. MEDLINE|
|4.||Grußendorf M, Reiners C, Paschke R, Wegscheider K: Reduction of thyroid nodule volume by Levothyroxine and Iodine alone and in combination: A randomized, placebo-controlled trial. J Clin Endocrinol Metab 2011; 96: 2786–95. MEDLINE|