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Surgical therapy for thyroid neoplasms is based on tumor histology and comprises stage-adapted procedures with a high degree of inter-individual variability. This can range from waiting and monitoring, to extensive multivisceral surgery. Grouping together histologically different types of malignancies leads to false assumptions when gauging the radicality of surgery necessary in each particular case. Surgical therapy requires not only an understanding of the biological behavior of the tumor and the risk that it or the therapy poses to the patient, but also knowledge of a wide surgical spectrum of limited and complex resection procedures in the neck and thorax region. The following recommendations are based primarily on the guidelines of the Surgical Working Group for Endocrinology of the German Society for General and Visceral Surgery as well as on the authors' own experience and, where indicated, the guidelines of other working groups.

Multinodular goiter is a frequent disease which plays a central role in the daily routine of general and visceral surgeons. Analyses of the national DRG statistics reveal that total thyroidectomy is increasingly replacing partial thyroid resections. This paradigm shift is substantiated by the comprehension of multinodular goiter as a disease affecting the whole organ as well as the fact that total thyroidectomy avoids high risk secondary interventions for incidental thyroid carcinomas and recurrent disease while offering comparable operative risks. However, the available evidence on operative results originates predominantly from thyroid centers and clinical data regarding long-term effects of thyroid hormone substitution following total as well as sub-total thyroidectomy are lacking. Therefore, the preservation of functionally relevant normal thyroid tissue retains its relevancy as an alternative treatment. If a comparably low operative risk can be guaranteed and considering the patient's compliance, life situation and wishes, total thyroidectomy represents the optimal therapy for bilateral multinodular goiter.

Background: Clinically relevant thyroid carcinomas can be found in 5-6% of nodular goiters which undergo surgery. Moreover, multinodular goiters fre- quently contain hot areas. Therefore, efficient and rational methods for the differential diagnosis and decision are required to identify those nodules with an increased cancer risk or those which are hot among the many thyroid nodules., Methods: Description of a newly revised and further guidelines and consensus statements as well as selected literature search., Results: Already history, ultrasound and TSH (thyroid-stimulating hormone) determination do allow a first risk assessment for the further diagnostic work-up. Fine-needle biopsy (FNB) offers the best sensitivity and specificity for the distinction between benign and malignant thyroid nodules. The combination of several clinical and ultrasound criteria and laboratory determinations (calcitonin) can help with the selection of thyroid nodules with scintigraphically normal or decreased uptake > 1 cm for FNB. However, the efficiency of FNB requires sufficient training and experience of both the cytopathologist and the person performing FNB., Conclusion: Whereas solitary thyroid nodules with a suspicion for malignancy should be referred to the surgeon, euthyroid thyroid nodules without clinical ultrasound or cytological indicators of malignancy may be followed up - possibly under medication -, if surgery is not indicated by local complaints, tracheal or mediastinal involvement.

Up to 15 % of the adult German population display an enlarged thyroid gland and up to 30 % present thyroid nodules. Iodine deficiency is the most important factor in the etiology of nodular goiter. Insulin-like growth factor-I is overexpressed in thyroids in severely iodine deficient areas. There is evidence that iodolactones are mediators of thyroid hormone autoregulation. However familial and twin studies demonstrated a genetic component in the etiology of nodular goiter. Linkage analysis identified two chromosomal regions (MNG-1, Xp 22) in multinodular goiter. Other possible candidate genes or markers such as TG, TPO, NIS, PDS and TSH-R were not identified. Nodular goiter certainly comprises a number of genotypes. TSH receptor mutations result in activation of the cAMP cascade. Cells with a constitutively activated cAMP cascade have an increased growth advantage due to their TSH independent cAMP stimulation. Alimentary iodine supply should be the first choice in primary prevention of nodular thyroid disease in iodine deficient areas, because prevalence of nodular goiter is negative correlated with individual iodine status in epidemiological surveys. Surgical removal of nodular goiters should include nearly the hold thyroid tissue to avoid recurrent goiter.

An optimal supply of iodine--150-200 microg/day--has not yet been secured in all regions and in all phases of life. The appreciable diminishment in thyroid gland mass in children and adolescents is, however, indicative of an improvement in this situation. In elderly persons, however, prophylactic measures do not result in struma or nodule regression. Nodules are found in some 40% of women and 28% of men older than 45. Medical treatment of nodular goiter is aimed at achieving a reduction in size or preservation of the status quo. Depending on the size of the goiter, iodine-deficiency goiter is treated with iodine or a combination of iodine and levothyroxine. In view of the pathogenesis and the marginal alimentary lack that still persists, there are no adequate arguments for L-thyroxine monotherapy of uncomplicated iodine-deficiency goiter.

Investigations within the framework of the thyroid gland initiative "Papillon" turned up an unexpectedly high level of pathogenic findings. Determination of TSH and sonography are considered the pillars of the diagnostic evaluation of the thyroid gland. Useful further investigations aimed at excluding functional disorders are, for example, the determination of FT3 and FT4 or a search for autoantibodies. To investigate suspicious nodules and to exclude malignant processes, additional scintigraphy and, were indicated, fine-needle puncture can be applied. Depending on the individual situation of the patient, the therapeutic option of choice is surgical operation or treatment with iodine-31 therapy. Medical treatment of nodular goiter is currently still controversial.

In the framework of the Thyroid initiative Papillon 2001 - 2002 thyroid nodules and sonographically detectable focal lesions with a diameter more than 5 mm were verified in 23.1% of 64.123 persons without a history of thyroid disease. The frequency of such findings was with 33.0% in 46-65 years old persons three times higher then in persons aged 18-30 years (9.6%). In the diagnostic workup thyroid cancer was detected in 15 patients operated on up to now (6 women and 9 men; papillary cancers in 12 cases, follicular cancers in 3 cases) The smallest tumor had a diameter of 1.3 cm, the mean diameter was 2.3 +/- 91 cm. In 3 patients the tumor had invaded the tissue beyond the thyroid capsule, in 4 cases multicentric growth was detected. Lymph node metastases were found in 7/15 cases and distant metastases in 2/15 cases. These result reveal, that thyroid cancer detected by chance may be relatively aggressive. In daily routine, sonographically detectable lesions with poor echogenicity, irregular margins or internal calcifications with a diameter of more than 1 cm should be clarified by fine needle aspiration biopsy.

Seasonal variations in the frequency of thyrotoxicosis are known for a long time. Both, variations in the temperature and in the iodine supplementation are believed to affect the incidence of the diagnosis of hyperthyroidism. Seasonal variation of the incidence of hyperthyroidism was investigated before and after increase of salt iodination in 1990/1991. In the period from January 1987 to December 1995 hyperthyroidism was diagnosed for the first time on 4711 patients in our department. This population was subdivided according to etiology (Graves' disease, autonomous nodular goiter) and grade of hyperthyroidism (preclinical or clinical form). The so formed groups were divided according to the month of diagnosis into further 12 subgroups. Significant differences in month to month variation were found in the patients suffering from Graves' disease and autonomous nodular goiter with preclinical hyperthyroidism after increased iodine supplementation. The peak incidence of the diagnosis occurred in June, July, and August. Our results indicate that improved iodine supplementation may be the main cause of seasonal variations in the incidence of thyrotoxicosis.

The frequency distribution of immunogenic and non-immunogenic hyperthyroidism (IH, NIH) was evaluated retrospectively in the former endemic goiter area of Berne over a 15-year period (1976, 1982, and 1991). Out of 12,320 patients referred for thyroid examinations, 9.1% were hyperthyroid. NIH still predominates with a constant frequency of 59%; but the ratio between toxic adenomas (TA) and multifocal functional autonomies (MFA) was significantly inversed, from 2.6 over 0.9 to 0.4. The frequency of TA decreased from 41% to 17% and that of MFA increased from 16% to 38%. The arithmetic mean age at diagnosis was constant: 53.9 (IH), 61.5 (TA) and 67.5 years (MFA). The decreasing frequency of TA over the last 15 years is explained by an increased but still insufficient iodine supply.