[L-thyroxine therapy in differentiated thyroid carcinoma: criteria for evaluation of TSH suppression]. / Leczenie L-tyroksyna zróznicowanego raka tarczycy: kryteria supresji wzglednej.

UNLABELLED: Life-time L-thyroxine therapy is obligatory in patients treated for differentiated thyroid carcinoma (DTC) in order to suppress serum TSH. The rationale for that is the TSH stimulation of follicular cells' growth and the presence of TSH receptors on DTC cells. Nevertheless, the exact criteria for TSH suppression in DTC are not specified and are a matter of discussion, stimulated by the recent progress in the evaluation of thyroxine side effects on bone and heart. The aim of the study was the optimalization of the reference range for TSH suppression in DTC patients in order to minimalize the risk of iatrogenic thyrotoxicosis. One hundred and twenty nine patients were randomly chosen among patients treated radically for DTC (116 females and 13 males). Basal and TRH stimulated TSH level, FT4 and FT3 serum level were estimated by microimmunoenzymatic method, while SHBG was estimated by immunofluorimetry. Full suppression (basal TSH < 0.05) was obtained in 64 patients (49%), submaximal suppression (TSH between 0.1 and 0.3 mU/l) was observed in 21 patients (16%). In 29 patients (22%) no suppression was obtained by the applied dose of thyroxine. The risk of iatrogenic hyperthyreosis, as judged by the increase of FT3 or SHBG, was found to be 38% in patients with full suppression and only 5% in patients with submaximal suppression (p < 0.05). CONCLUSION: 1. Suppression of TSH secretion was achieved in 80% of patients with differentiated thyroid carcinoma. The control of TSH level must be controlled every 3 months in 5 first years of therapy. 2. The optimal serum TSH level for L-thyroxine therapy in asymptomatic patients after radical treatment of differentiated thyroid carcinoma ranges between 0.1 to 0.3 mU/L. This range ensures the expected suppression of TSH with only minimal risk of iatrogenic hyperthyreosis.

[Effects of L-thyroxine suppressive therapy on cardiac mass in patients with differentiated thyroid cancer]. / Wplyw leczenia supresyjnego L-tyroksyna chorych na zróznicowanego raka tarczycy na mase miesnia sercowego.

Patients with differentiated thyroid carcinoma (DTC) receive a life time l-thyroxine therapy in suppressive doses and may exhibit signs of cardiac hypertrophy. The aim of the study was to analyze the left ventricle mass parameters by echocardiography in patients treated with suppressive doses of thyroxine and to relate them to the possible occurrence of cardiac arrhythmias. Ninety four patients aged 19-70 years treated chronically with l-thyroxine were randomly chosen from the population of patients with DTC without concomitant diseases of circulatory system. They were divided into two subgroups according to the length of thyroxine therapy (< 60 months and > or = 60 months). Control group consisted of 41 healthy volunteers, aged 22-73 years. Heart muscle dimensions were measured by echocardiography. Left ventricle mass (LVM) and mass index (LVMI) was calculated. Electrocardiography according to Holter was carried out in 57 patients. The results of echocardiography in the whole group of patients did not differ significantly from the control group, although a tendency towards higher dimensions of the left ventricle was observed. No correlation of hormonal parameters, or thyroxine dose, with LVM or results of Holters ecg was noted. When patients were subdivided into two groups, according to the duration of therapy, significantly higher values of LVM (215 +/- 64 g versus 186 +/- 55; p < 0.05) and LVMI (114 +/- 31 g/m versus 102 +/- 23 g/m; p < 0.05) were observed in patients treated > or = 60 months in comparison to the control group. When results of Holter's ecg in patients with increased LVMI were analyzed, cardiac rhythm disturbances were stated in 50% of them, but most were of minor clinical relevance. Suppressive l-thyroxine therapy does not induce significant left heart hypertrophy during the first 5 years of treatment. Patients treated through a longer period of time should be controlled by echocardiography because of the increasing risk of the left ventricle hypertrophy and arrhythmia.

[Prospective analysis of criteria for interpreting measurements of thyroglobulin serum concentration during conditions of endogenous TSH stimulation in serum of patients with differentiated thyroid carcinoma]. / Prospektywna analiza kryteriów interpretacyjnych oznaczania stezenia tyreoglobuliny w warunkach stymulacji endogennym TSH w surowicy chorych na zróznicowane raki tarczycy.

The aim of this study was the assessment of diagnostic value of thyroglobulin serum measurement in patients with DTC during endogenous TSH stimulation. Thyroglobulin was measured by immunofluorometric method (Delfia-Wallac) in patients after combined surgery and I131 ablation. Predictive values for two threshold levels 10 and 30 ng/ml were compared. At 5 years follow up it has been demonstrated, that Tg values higher than 10 ng/ml were the true signals of DTC relapse only in 46% patients. Tg values higher than 30 ng/ml were associated with disease progression in 65% of patients. Thus, we accept Tg concentration of 30 ng/ml measured during endogenous TSH stimulation as a good cut-off limit for the detection of DTC progression. Reduction of this threshold up to 10 ng/ml is associated with the increased risk of false positive results.

[Comparison of efficacy of various methods of thyroglobulin measurements in differentiated thyroid cancer]. / Porównanie skutecznosci róznych metod oznaczania tyreoglobuliny jako markera zróznicowanego raka tarczycy.

Monitoring patients with differentiated thyroid carcinoma (DTC) by thyroglobulin (Tg) measurements requires selecting optimal methods used for detection of this marker. An increase the thyroglobulin concentration in serum is a predictor of tumor recurrence. All serum thyroglobulin assays can be falsified by presence of Tg autoantibodies, which are present in approximately 20% of DTC patients. The aim of this study was a comparison of the clinical utility of two different methods for determining serum Tg concentration in monitoring patients with DTC during thyroxine treatment. Tg concentration was measured in serum samples of 1530 patients with DTC during replacement thyroid hormone using two methods: fluoroimmunometric assay (IFMA) Wallac Delfia Thyroglobulin and immunoradiometric assay (IRMA) Brahms DYNOtest Tg-S. 1847 values of Tg concentration and recovery test detected between 1992 and 1995 years using IFMA methods and 1187 values of Tg and thyroglobulin autoantibodies concentration measured in 2000 year using IRMA methods were also included. The correlation between Tg values in all patients group wasn't good (r = 0.83; p < 0.05), but when we excluded patients with incorrect recovery test determined by IRMA, the correlation factor was higher (r = 0.94; p < 0.05). The estimation of Tg recovery test obtained in IRMA assay eliminated from monitoring only 3% patients with DTC, when IFMA assay excluded nearly 1/5 patients, whereas the estimation Tg autoantibodies 7% from all patients. The IRMA method is the most resistant to interference and allows to monitor a reliably greater group of patients with DTC during thyroxine treatment.

[Evaluation of bone density in women after thyroid cancer surgery and treatment with suppressive doses of L-thyroxine]. / Ocena gestosci kosci u kobiet po operacji raka tarczycy, leczonych supresyjnie L-tyroksyna.

The aim of this work was to evaluate the degree of bone resorption and incidence of osteoporosis in female postmenopausal patients with differentiated thyroid cancer treated with suppressive doses of thyroxine. During the regular follow-up of women with differentiated thyroid cancer, densitometry of lumbar spine (L2-L4) and femoral head were performed. urine concentration of deoxypyridinoline and calcium-phosphate metabolism were also evaluated. Osteoporosis was diagnosed in 11% of patients, all without hormone replacement therapy (HRT). Mean bone density was significantly higher in patients treated with HRT. A decrease in bone mass was related to the duration of thyroxine therapy. The best results of bone mass density were obtained in patients on HRT and with short duration of thyroxine therapy. Deoxypiridinoline estimation did not exhibit significant differences between groups, however it was useful in the individual evaluation of bone resorption.