The letters we received in response to our article offer another opportunity to clarify some of the key messages of our CME article.
Unfortunately, only few studies that satisfy the criteria of evidence-based medicine have been conducted for thyroid disorders, although thyroid disease constitutes a very common problem. A comment on NNT/NNH would have been highly desirable but remains impossible due to lack of data and will therefore need to be an objective of future research.
We agree with our correspondents’ comments on the low sensitivity and specificity of scintigraphy as a method to detect cancer in patients with thyroid nodules. Thyroid scintigraphy has an altogether different purpose, namely, that of detecting thyroid autonomy, and is an excellent tool for just that. Especially on the background of an ageing population and the frequent exposure to contrast medium during CT scans and cardiac catheterization, the risk of iodine-induced hyperthyroidism due to thyroid autonomy should not be neglected. These insights are also reflected in the 2010 recommendations from AACE/AME/ETA.
Measurement of calcitonin in nodular thyroid disease (thyroid autonomy is the exception) has for many years been included in the European recommendations for the diagnostic evaluation of thyroid nodules (among others the thyroid section of the German Endocrine Society, the European Thyroid Association, AACE/AME/ETA). The notion “controversial” applies to the reluctance among US doctors to use the procedure, which has other reasons than confirmed evidence for the early detection of MTC: e.g. the aspect of cost and, in the past, the unavailability of a stimulation test in the US.
In Germany, one-time measurement of calcitonin in the initial work-up of nodular thyroid disease is a blessing, since it helps to detect MTC at an early stage. Thyroid specialists may advise in situations where interpretation of calcitonin levels is difficult. Operating on a euthyroid nodular goiter without preoperative calcitonin measurement is obsolete in Germany today.
Measuring thyroid autoantibodies is not routinely recommended in patients with nodular goiter . However if ultrasonography has raised the suspicion of autoimmune thyreopathy, measurement of e.g. TPO antibodies may be helpful (1).
The LISA study was conduced over one year; the study design is exemplary and it provides the only recent evidence for Germany, especially on the background of the German tradition of medical treatment of thyroid nodules/nodular goiter. As regards volume reduction, iodine was shown to be inferior to the combination treatment of iodine plus levothyroxine at one-year follow-up. A longer study period for LISA would have been highly desirable, in order to clarify several important aspects of management discussed in the article.
The reported follow-up interval in nodular goiter is controversial, and unfortunately no evidence exists for this either. Thus it is important to make the decision on an individual case basis (size of nodule, risk , probability of developing symptoms). The indication for treatment is naturally defined by balancing potential benefits, and risks. This key message was presented in our article just before the comments on treatment options.
The European and North American recommendations (AACE/AME/ETA) explicitly advise against percutaneous sonography-guided percutaneous alcohol instillation, because:
1. Studies showed recurrent autonomies over time, and
2. The options of radio-iodine treatment or thyroid surgery constitute reliable and safe interventions for the ablation of autonomies.
In selected cases, cysts still do constitute an indication for percutaneous sonography-guided percutaneous alcohol instillation.
We strongly advice against the proposed diagnostic and therapeutic nihilism when dealing with thyroid patients.
To wait for complications and risks would mean ignoring the following aspects:
1. Evidence has shown that thyroid malfunction is common in the general population and is associated with morbidity.
2. Long-term complications may arise from thyroid disorders that for patients and doctors are seemingly asymptomatic.
3. Thyroid autoimmunity is common and relevant in women who wish to start a family.
4. Clinical symptoms of thyroid malignancy indicate a tumor at an already advanced stage.
What is needed is a rational management of thyroid nodular disease, and our review article is intended to provide some decision aids and explanations to this end.
Fortunately, an announcement of “guidelines in development” also provides an opportunity to include corrections. In view of the responsibility for the well-being of patients receiving healthcare from GPs, we sincerely hope that this will be done, and we strongly invite the colleagues involved in guideline development to discuss this issue with the thyroid section of the German Endocrine Society.
Prof. Dr. Dr. med. Dagmar Führer
Klinik für Endokrinologie und Stoffwechselerkrankungen, Essen
Conflict of interest statement
Professor Führer is in receipt of honoraria for consultancy work from Astra-Zeneca and Pfizer. For continuing medical educational events and conferences she has received travel expenses and honoraria from Merck, Sanofi-Aventis, Ipsen, Pfizer, Novartis Amgen, and Astra-Zeneca. For conducting commissioned clinical studies she has received honoraria from Astra-Zeneca, Pfizer, Ipsen, Novartis, Bayer, Lilly, Novo Nordisk, Merck, and Sanofi-Aventis.
|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|