Free communications - Thyroid carcinoma
	There were several reports concerning medullary carcinoma. Colombo-Benkmann, Heidelberg, Germany, reported results of methoxy-iso-butyl-isonitril (MIBI) 99mTC-scanning to localize recurrent medullary thyroid carcinoma (MTC) in 11 patients with no or suspected recurrences. One patient was correctly diagnosed as being free of recurrence, whereas in the remaining 10 patients 14 areas were correctly localized by this technique, as confirmed histologically. (Comment: We like to see results in more patients using this promising radio-pharmacon.) Heshmati et al., Paris, France, studied expression of calcitonin gene-related peptide (CGRP) and of calcitonin (CT) after stimulation with pentagastrin in 13 patients with MTC and in 16 normals. All patients reacted dramatically with regard to CT with a mean increment after stimulation of 1631 % over basal values. Only 3MTC patients had an increment higher than 100% over basal values regarding CGRP expression. Hardly any stimulation of expression of both substances was seen in controls. It is concluded that in most patients with MTC there is a dissociation between CGRP and CT secretion, although both peptides are encoded by the calcitonin gene in the thyroid and in the nervous system. Robinson, Sidney, Australia, studied mutations in the RET oncogen known to occur in families with MTC and multiple endocrine neoplasia type 2A (MEN 2A). Seven separate mutations have been found in 15 Australian families. They performed a thyroidectomy in a patient on the basis of a suspected gene mutation, although in this subject the CT peak after pentagastrin was just below the upper normal limit (189 pg/ml) being 182pg/ml. This patient had histologically confirmed c-cell hyperplasia as well as parathyroid hyperplasia. Three at risk individuals in MEN 2A families had calcitonin peaks at 194 pg/ml, 189 pg/ml and 160 pg/ml, and were shown not to be gene carriers, and thyroidectomy was not performed. A fourth family member had a peak of 98 pg/ml, and underwent thyroidectomy. The thyroid gland was normal and he was subsequently shown not to be a gene carrier. These studies indicate the utility of direct mutation detection and pentagastrin stimulation in the management of the MEN 2 syndromes. Pacini, Pisa, Italy, reported screening for RET gene mutations in MEN 2 A and B, and in sporadic MTC. They found mutations both in families with MEN 2A and MEN 2B (only 1 family). Furthermore somatic point mutations were found in 50 % of sporadic MTC. Finally a RET mutation was also found in a case of a combination of MEN 2A and cutaneous lichen amyloidosis. RET mutations in the tumor DNA were found in 9/16 sporadic patients but in 2patients the mutation was also present in constitutional DNA indicating that these cases were wrongly classified as sporadic. Also several reports were presented concerning differentiated thyroid carcinoma. Kolenda, Toronto, Canada, retrospectively evaluated the utility of near total thyroidectomy (NTT) in three groups of patients: Gr I (n = 64) had NTT for solitary nodule; Gr II (n = 17) had completion thyroidectomy following previous lobectomy and Gr III (n = 14) had NTT for palpable bilateral disease. In Gr I patients 73.5 % had ca., confined to index lobe only; 18.8 % had bilateral ca., and 7.8 % had benign disease only in index lobe. In Gr II residual ca. was detected in 5/17 (29 %) after completion thyroidectomy. In Gr III bilateral ca. was detected in 57 %. It is concluded that NTT ensures a more complete irradication and enhances effectiveness of radioiodine ablation as well as subsequent utility serum TG measurement as a marker for recurrence. The authors also found that contralateral recurrences are often not detectable by palpation, 131I scanning, or ultrasound. Baqai, Los Angeles, CA, USA, reported 18FDG-PETscanning in 11 patients with differentiated thyroid carcinoma, who had negative (2 - 5 mCi) 131I diagnostic scans and persistently detectable TG serum values, while being on T4 suppression. Patients were initially treated with total thyroidectomy and 131I ablation. All patients showed abnormal 18FDG-uptake in one or more sites. It is concluded that this technique of scanning provides a sensitive tool for diagnosing differentiated thyroid carcinoma localization, especially in patients with detectable serum TG and negative diagnostic 131I scans. This technique avoids the need for withdrawal of T4. A disadvantage is, that the technique is very expensive. (Comment: This is a very interesting and potential important report and confirms the potential use of FDG as a non-specific radiopharmacon for the detection of cancer sites. It is not known if in this study positive scanning results were histologically verified as tumorsites.) About another technique, that of 99mTc-sestamibi (Methoxy-iso-Butyl-Isomitrile, MIBI) scanning in differentiated thyroid carcinoma was reported by Elser, Heidelberg, Germany. Results were compared with 131I scintigraphy (ISc) and 46 patients with suspected or proven recurrence after total thyroidectomy and ablative radioiodine therapy were investigated. Local recurrences were detected in 94 % in MIBI and 63 % in ISc. Pulmonary localizations and skeletal localizations were detected in 77 and 83 % respectively in MIBI and in 39 and 44 % in ISc. The authors stress the importance of MIBI scanning in patients suspected of having local recurrences in differentiated thyroid carcinoma. Basschieri, Pisa, Italy, investigated the prevalence of thyroid nodules in 59 male medical X-ray workers, and compared the results with a control group of 130 males without occupational radiation exposure. Ultrasound scanning revealed in 41 % of exposed subjects thyroid nodules versus 19 % in controls. Fine needle aspiration did not disclose thyroid malignancy in any case. Thyroid function parameters were normal in all subjects of both groups. Radiation induced nodule formation was especially higher in younger subjects. Kimura et al., Basel, Switzerland and Sao Paulo, Brasil, studied the expression of transforming growth factor (TGF) b1 and b3, using immunoenzymatic staining after tissues have been exposed to antibodies against these TGF's. Ten benign and 10 malignant human thyroids were studied and it was found, that distribution of both TGF's was homogenous in malignant tumors, but in benign tumors both TGF's were only expressed in morphologically proliferative areas. From these results it is concluded that TGF b1 and b3 may contribute to benign and malignant growth in human thyroids. Willemshurst, St. Leonards, Australia, reported the outcome of treatment of differentiated thyroid carcinoma in 658 patients over 26 years. The treatment protocol was uniform in that a total thyroidectomy, if necessary with neck dissection, was performed followed by postoperative 131I scan and, if residual uptake was present, an ablative dose of 150 mCi 131I. T4 was given in suppresive doses and 131I scans, and serum TG measurements were repeatedly done, and 150 mCi 131I was administered when uptake of radionuclide was detected. The papillary carcinoma group consisted of 489 patients and the follicular carcinoma group of 169 patients. Ten years survival rates were 94 % (pap. ca.) and 88 % (fol. ca.). Survival was not significantly different between male and female patients, nor between both carcinoma groups. Age was the most significant predictor of survival. Compared with age <40 years, risk of dying was increased 29 times for age group 40-70 years, and 270 times for patients over 70years. The presence of metastases increased risk of dying by a factor 2.1 and larger tumor size was associated with increased risk of death (p = 0.004).