Conclusion
	Thyroid carcinomas are the most frequent endocrine malignancies displaying a wide variety of different types. Fortunately the most frequent ones are the less aggressive differentiated ones with a favourable prognosis. The good prognosis is, however, dependent from an early initial treatment and also an early treatment of local relapse/metastases. A good diagnostic work-up of thyroid nodules is therefore important and a careful long-term follow-up mandatory. Due to the occasional occurrence of very late metastatic disease (e.g. 30 years after initial treatment)(2) the follow-up should be life-long although the follow-up intervals can be extended with time. The introduction of the tumour markers, in particular Tg for the differentiated carcinomas, has substantially facilitated the post-therapy follow-up but it has to be kept in mind that there are pitfalls in the use of serum Tg as the only follow-up variable. For that reason it is still recommended to perform regular I-131 wbs in many of the patients, yet with longer intervals. In patients with presence of TgAb in serum I-131 wbs is probably necessary at more frequent intervals. No prospective follow-up studies have been performed to clearly identify patients in need of a frequent assessment with both serum Tg and I-131 wbs and those needing only serum Tg measurements during levothyroxine therapy. However, the available retrospective sudies on mobidity and mortality indicate that the follow-up could probably be stratified according to risk factors, i.e. in a young patient with a non-metastatic papillary carcinoma, having had a total thyroidectomy, showing no uptake after ablation with I-131, with unmeasurable Tg after therapy and without TgAb does not require life-long wbs but only measurement of serum Tg during treatment with levothyroxine.