Influence of female sex hormones on thyroid parameters determined in a thyroid screening.

This is a cross-sectional study with a non-randomly selected population to ascertain the influence of female sex hormones on thyroid function. TSH, TT4, FT4, TT3 and FT3 were determined in 251 women using either oral hormonal contraceptives or hormone replacement treatment, 255 women not taking either, and a control group of 900 men. Women with normal thyroid morphology using oral hormonal contraceptives in the pre-menopausal group had a significantly higher TT4 and TT3, and lower FT3, respectively, than both non-users and men. FT4 and TSH remained unchanged. In the peri-/post-menopausal group, thyroid function of women using hormone replacement treatment was not significantly different from non-users, but either women still had a significantly lower FT3 than men. We conclude that oral hormonal contraceptives and hormone replacement treatment increase TT4 and TT3 and do not influence FT4 and TSH. They decrease FT3 which is in contrast to what would be expected theoretically and what has been observed in earlier studies.

Autoantibodies to thyroperoxidase (TPOAb) in a large population of euthyroid subjects: implications for the definition of TPOAb reference intervals.

OBJECTIVE: Measurement of autoantibodies against thyroperoxidase (TPOAb) plays an important role in the diagnosis of autoimmune thyroid disease. The assessment of reference intervals for TPOAb, however, is a controversial issue since elevated TPOAb values are sometimes found in subjects without other evidence of thyroid disease. METHODS: TPOAb were measured in 1,295 euthyroid individuals using a highly sensitive, fully automated chemiluminescence assay (Advantage A-TPO, Nichols Institute Diagnostics, CA, USA). The study subjects participated in a population study on the prevalence of thyroid disorders in the German federal state of Saxony, an area of mild iodine deficiency. RESULTS: TPOAb above the detection limit of 0.45 IU/ml were found in 1,277/1,295 euthyroid individuals. TPOAb values in the low measurable range below 1.1 IU/ml followed a normal distribution, and this was independent of age and sex. When using a cut-off value of 1.1 IU/ml, which corresponds to a sensitivity of 79% and a specificity of 95% resulting from the receiver-operator characteristic plot for discrimination between a main type and other types with a higher mean value of TPOAb, elevated TPOAb were found in 14.4% of euthyroid men and in 25.8% of euthyroid women. CONCLUSIONS: The results demonstrate for the first time that TPOAb are detectable in nearly all euthyroid individuals and that TPOAb values in the low measurable range are normally distributed. The distribution of TPOAb values in the low range is independent of age and sex. Based on these data, reference intervals for TPOAb can be defined that are independent of the population investigated. The clinical significance of slightly elevated TPOAb, however, has still to be defined by prospective studies.

Dosimetry of 188Re-hydroxyethylidene diphosphonate in human prostate cancer skeletal metastases.

UNLABELLED: 188Re-Hydroxyethylidene diphosphonate ((188)Re-HEDP) was used in previous studies for the palliative treatment of metastatic bone pain. However, the kinetic and radiation-absorbed doses have not been well documented. Therefore, the aim of this study was to gather dosimetric data for (188)Re-HEDP. METHODS: Thirteen prostate cancer patients with skeletal involvement were treated with 2,700-3,459 MBq (mean dose, 3,120 MBq) (188)Re-HEDP. Patients underwent whole-body scans 3, 20, and 28 h after therapy. The effective half-life, residence time, and radiation-absorbed dose values were calculated for the whole body, bone marrow, kidneys, and bladder as well as for 29 bone metastases. The urinary excretion rate was determined in 6 urine samples of each patient collected over 48 h at 8-h intervals beginning immediately after the administration of (188)Re-HEDP. After injection of (188)Re-HEDP, blood samples were taken weekly for 6 wk, and platelet and leukocyte counts were performed. RESULTS: The mean effective half-life was 15.9 +/- 3.5 h in bone metastases, 10.9 +/- 2.1 h in the bone marrow, 11.6 +/- 2.1 h in the whole body, 12.7 +/- 2.2 h in the kidneys, and 7.7 +/- 3.4 h in the bladder. The following radiation-absorbed doses were calculated: 3.83 +/- 2.01 mGy/MBq for bone metastases, 0.61 +/- 0.21 mGy/MBq for the bone marrow, 0.07 +/- 0.02 mGy/MBq for the whole body, 0.71 +/- 0.22 mGy/MBq for the kidneys, and 0.99 +/- 0.18 mGy/MBq for the bladder. (188)Re-HEDP showed a rapid urinary excretion within the first 8 h after therapy, with 41% of the (188)Re-HEDP administered being excreted. Forty-eight hours after therapy, the excretion rate was 60% +/- 12%. Only 1 patient showed a decrease of platelet count below 100 x 10(9) counts/L. None of the patients presented with a decrease of leukocyte count below 3.0 x 10(9) counts/L. CONCLUSION: (188)Re-HEDP is an effective radiopharmaceutical used in the palliative treatment of metastatic bone pain. The radiation-absorbed dose is acceptable for bone pain palliation with low doses for the normal bone marrow and the whole body.

Retinoic acid for redifferentiation of thyroid cancer--does it hold its promise?

OBJECTIVES: To evaluate the effectiveness of isotretinoin for improving (131)I uptake in recurrent/metastasized thyroid cancer with no/insufficient (131)I uptake. DESIGN: Retrospective analysis of 25 patients treated between June 1999 and May 2001. METHODS: 15 female and 10 male patients were given isotretinoin at 1 mg/kg for 3 months, followed by (131)I treatment. All patients received a (131)I scan 72 h after administration, thyroglobulin measurement, chest X-ray and ultrasound of the neck, and some patients underwent a (18)F-fluorodeoxyglucose (FDG) positron emission tomography (n=14) and computed tomography scan of the chest (n=11). RESULTS: In two out of 14 patients with raised thyroglobulin but no (131)I uptake, a slightly improved (131)I uptake was seen. In a further 11 patients an improvement of (131)I uptake of known lesions was desired or further non-(131)I-accumulating lesions were known. A dosimetrically relevant improvement of uptake was seen in three of these patients. (18)F-FDG uptake and thyroglobulin did not correlate with the success/failure of the isotretinoin treatment. Side effects including a strong "sunburn", cheilitis, mucositis, conjunctivitis and raised transaminases occurred in two-thirds of patients. They were of an overall tolerable level and were reversible after isotretinoin had been stopped. CONCLUSION: From our clinical experience over a period of 2 years we conclude that the therapeutic effect of isotretinoin in thyroid cancer is certainly less than previously reported. An indiscriminate use of isotretinoin in all patients with otherwise untreatable thyroid cancer cannot be recommended.

FDG-PET in the pretherapeutic evaluation of primary squamous cell carcinoma of the oral cavity and the involvement of cervical lymph nodes.

PURPOSE: The diagnostic role of positron emission tomography (PET) with 2-deoxy-2-[18F]fluoro-D-glucose (FDG) in squamous cell carcinoma of the oral cavity is evaluated. PROCEDURES: In 38 patients, the results of FDG-PET, magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound were compared. The standard uptake values (SUV) of FDG-PET were correlated to histopathological grading and DNA-image cytometry. RESULTS: In the case of lymph node metastases, the sensitivity of FDG-PET (93%) was higher than the sensitivity for the compared methods. The specificity was best for CT. SUVs of diploid tumor cell lines seemed to be lower than in non-diploid tumor cell lines. CONCLUSIONS: The high sensitivity and the high negative predictive value of PET may lead to more restrictive therapeutic regimens regarding lymph node metastases. Studies are necessary regarding possible relationships between glucose metabolism and tumor grading.