Serum thyroglobulin concentration in nontoxic goiter and response to surgery with special reference to risk of goiter relapse

Effectiveness of prophylactic therapy on goiter recurrence in an area with low iodine intake--a sonographic follow-up study

There is no agreement as to whether or not drug treatment after surgery for nodular goiter is effective in preventing recurrence of goiter. Data about recurrences in areas of marginally low iodine intake (like Germany) vary widely. Therefore, we performed a retrospective study in 104 patients who had been treated surgically because of benign uninodular or multinodular goiter. The mean follow-up period was 6.4 years (minimal 1 year) with at least three examinations. Thyroid ultrasound with volumetric analysis was recorded in each patient. Thirty-two patients did not receive any prophylaxis, 50 patients were treated with L-thyroxine, 17 patients with a combination of L-thyroxine and iodine and 5 patients with iodine alone. Recurrence of goiter was documented in 28.0% of the untreated patients and in 8.9% of the patients on prophylaxis (P < 0.05). The mean increase of thyroid volume was 7.3 ml versus 3.1 ml in patients without versus with prophylactic drug treatment (not significant). No significant correlation was found between the increase of thyroid volume and age of the patients, follow-up time, or initial thyroid volume, respectively. These data clearly demonstrate the effectiveness of prophylactic drug therapy to prevent recurrence of goiter after thyroid surgery in an iodine-deficient area.

Endemic goiter and endemic thyroid disorders

The primary role of iodine deficiency in goitrogenesis and the prevention and treatment of endemic goiter by iodine supplementation is firmly established. Unfortunately, implementation of iodine prophylaxis programs has met with considerable technical and socioeconomic difficulties. Besides, lack of knowledge concerning some of the other causative factors of endemic goiter has prevented development of appropriate measures for its complete eradication in those areas where goiter persists in spite of prolonged and adequate iodine supplementation. At present, no less than 5% of the world's population have goiters and associated disorders, resulting in a public health and socioeconomic problem of major proportions. Seventy-five percent of people with goiter live in less developed countries where iodine deficiency is prevalent. Goiter prevalence rates of more than 50% and the highest frequency of severe cases of iodine deficiency disorders, namely, cretinism, congenital hypothyroidism, and various degrees of impairment of growth and mental development are found in endemic areas with extreme iodine deficiency. Goiters are usually multinodular and of very large size, producing, on occasion, signs of compression that require surgery. Recurrence rates are as high as 25-30% and second surgery accounts for 16% of all thyroidectomies. Unfortunately, most of these goiters occur in areas with highly restricted medical and surgical facilities. Twenty-five percent of people with goiters live in more developed countries where goiter continues to occur in certain areas despite iodine prophylaxis. Iodine-sufficient goiters are associated with autoimmune thyroiditis, hypothyroidism, hyperthyroidism, and thyroid carcinoma. Goiter is of considerable surgical significance in iodine-sufficient endemic areas and, to a lesser degree, in nonendemic areas where it is called "sporadic" goiter. Recurrence rates of iodine-sufficient goiter are 10-19% following thyroidectomy. Since most of these goiters grow by mechanisms other than increased thyrotropin (TSH) stimulation, treatment with suppressive doses of L-thyroxine is inefficient and, because of possible complications, not recommended. Although Graves' hyperthyroidism is not directly related to endemic goiter, it does relate adversely with ingestion or administration of iodine. At present, Graves' disease is treated with 131I or antithyroid drugs in more than 90% of the cases. The incidence rates of papillary, follicular, and anaplastic thyroid carcinomas appear to be related to endemic goiter and iodine supplementation, with surgery being required in essentially all of these cases.

Anti-thyroid peroxidase antibodies in thyroid disorders and non-thyroid autoimmune diseases

A new commercial method for measurement of anti-thyroid peroxidase (anti-TPO DYNOtest, Henning, Berlin) was evaluated in normal subjects and in patients with autoimmune thyroid and non-thyroid diseases, and compared to an immune fluorescence method for measurement of anti-microsomal antibodies (MicAb), and a radioimmunological method for quantifying thyroglobulin antibodies (TgAb). The majority of normal subjects had anti-TPO levels below 52 U/ml and patients with Hashimoto's thyroiditis had levels above 200 U/ml, with a good correlation to MicAb. In other autoimmune thyroid diseases the correlation was less pronounced. In non-thyroid autoimmune diseases MicAb showed falsely positive reactions in the presence of other autoantibodies, e.g. mitochondrial antibodies. The present study indicates that the anti-TPO method should probably replace measurements of MicAb for routine clinical use, thus providing a sensitive, precise, antigen specific method with the ability to reveal quantitative fluctuations. The study also indicates that TgAb could be abolished in routine diagnosis of autoimmune thyroid diseases and be reserved for special clinical situations, research purposes as well as measurement in sera before evaluation of serum thyroglobulin levels.