Familial medullary thyroid carcinoma

Surgical management and follow-up of medullary thyroid carcinoma

Between 1977 and 1990 we operated on 33 patients with medullary thyroid carcinoma. We performed total thyroidectomy in 31 patients and central node dissection and/or lateral modified node dissection in 21 patients (63.3%). Two patients underwent radiotherapy after subtotal resection and tracheostomy. No perioperative death occurred. Twenty-five patients were followed (mean follow-up, 63.8 months) and 8 others were unavailable for follow-up. Three patients (1 with multiple endocrine neoplasia type IIB, 2 sporadic with distant metastases) died of their disease at 12, 18 and 36 months after initial operation. Of the remaining 22 patients, 4 with stage II disease were normocalcitoninemic even with pentagastrin stimulation, following total thyroidectomy and bilateral modified neck dissection and central node dissection. Eighteen other patients continued to have elevated calcitonin levels postoperatively. Only 10 patients with known cervical metastatic disease were reoperated upon. We performed extensive node dissection in all. In addition we resected recurrent tumor from the thyroid bed in 4 patients. Despite these extensive reoperations no patient became normocalcitoninemic. At the completion of the study (December 1991), 22 of the 25 patients followed were alive: 4 patients with normal calcitonin levels, baseline and after pentagastrin stimulation, and 18 with persistent mildly elevated calcitonin levels but no other evidence of disease. Our experience supports a very aggressive surgical approach at the time of the first operation for patients with medullary thyroid carcinoma. A lesser operation usually resulted in residual medullary thyroid carcinoma in the neck. We demonstrate the difficulty of achieving a cure by reoperation once the tumor becomes demonstrable by localization studies.

Thyrotrophin releasing hormone induced calcitonin secretion in patients with medullary carcinoma of the thyroid

An i.v. bolus injection of 500 micrograms TRH caused a prompt increase in plasma calcitonin (CT) in two patients with medullary thyroid carcinoma (MTC). In case 1 with a sporadic MTC, plasma CT increased from 0.32 ng/ml to 0.70 ng/ml 2 min after TRH. In the second case with multiple endocrine neoplasia (MEN) type II, plasma CT increased from 0.39 ng/ml to 4.7 ng/ml 2 min after the injection. None of five normal healthy subjects and a patient with thyroid follicular adenocarcinoma had significant changes in plasma CT levels after TRH. Studies with monolayer cultures of MTC cells derived from one patient revealed that TRH stimulated CT release. Incubation of the cells with TRH of 10(-6) M or 10(-5) M for 1 h increased CT concentration in the medium to 140% or 182% of the control level, respectively. Under the same conditions, pentagastrin (10(-6) M) increased CT concentration in the medium to 156%. These results indicate the direct stimulatory effect of TRH on CT secretion in the patients with MTC.

Evaluation of provocative tests in suspected medullary carcinoma of the thyroid:heterogeneity of calcitonin responses to calcium and pentagastrin

Abnormal calcitonin secretion provides a reliable marker for the presence of medullary carcinoma of the thyroid (MCT) and its precursor form, C-cell hyperplasia (CCH). Since this tumor may be transmitted by a dominant autosomal gene, the coincidence of a sensitive marker and an easily identified "at risk" population affords an unusual opportunity for cancer prophylaxis. To evaluate the specificity and sensitivity of provocative tests used for detection of C-cell disease, we have compared the calcitonin (hCT) responses to calcium (3 mg/kg body weight over 10 minutes intravenously), pentagastrin (0.5 microgram/kg body weight), and injection of calcium (1.0 mg/kg body weight) plus pentagastrin (0.25 microgram/kg body weight) over 60 seconds in 13 patients with subsequently proven MCT or CCH and in 31 normal volunteers. The ranges of hCT observed in normals after injection of pentagastrin and combined calcium and pentagastrin were lower than those seen in all nine patients with MCT. One subject, the only MCT patient with normal basal hCT values, had a normal response to calcium whereas all others achieved supranormal levels. Basal hCT levels were normal in the four patients with CCH but the hCT response to calcium was to a value in excess of 300 pg/mL, a level exceeded by only 3 of 31 normal subjects; the hCT response to pentagastrin in CCH and in normal subjects was indistinguishable. Combined calcium and pentagastrin administration was associated with abnormal hCT responses in two of the CCH patients and in the MCT patient with a normal response to calcium.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple endocrine neoplasia syndromes

The multiple endocrine neoplasia (MEN) syndromes are characterized by autosomal dominant inheritance with a high degree of penetrance but varying expression. This review gives a classification of these syndromes and a short summary of the historical background. The pathogenesis of the disease and its possible origin in the APUD cell system are discussed together with the mechanisms underlying normal and ectopic hormone production by MEN tumors on the basis of recent findings in molecular endocrinology. The natural history and the clinical manifestations of the different syndromes are described. The sensitivity and discriminative capacity of the tests used to detect the syndromes in an early stage are compared. The choice of therapy and criteria for the timing and extensiveness of treatment are also considered. Lastly, problems associated with the ethical and legal aspects of screening, central registration, and monitoring of relatives at risk are described.

Familial medullary thyroid carcinoma in multiple endocrine neoplasia (MEN) IIa: diagnosis and problems in treatment

A family with MEN IIa (medullary thyroid carcinoma (MCT), pheochromocytoma and hyperparathyroidism) was identified. Three relatives had been treated for MCT earlier. Eleven asymptomatic family members had elevated pentagastrin (PG)-stimulated serum immunoreactive calcitonin (i-CT) concentrations, including one who earlier had a pheochromocytoma removed. Nine of these subjects underwent thyroidectomy, and histological examination revealed multifocal MCT in all. Although surgery was judged complete in all, elevated PG-stimulated serum i-CT levels postoperatively indicated residual disease in 5. The natural history of MCTs in the present family varied, with most cases behaving benignly. Occasionally, however, the disease pursued an aggressive course. As MCT often metastasizes before being clinically evident, high cure rates can only be obtained by early diagnosis and treatment, possibly in the pre-metastasizing phase of C-cell hyperplasia, detectable only by elevated PG-stimulated serum i-CT levels.

Pentagastrin, calcium and whisky stimulated serum calcitonin in medullary carcinoma of the thyroid

The efficiency of pentagastrin, calcium and whisky in raising serum immunoreactive calcitonin (S-iCT) concentrations was analysed in 6 patients with medullary carcinoma of the thyroid and in 8 healthy controls. All 6 patients responded to pentagastrin with a significant increase in S-iCT, 5 responded to calcium and only 3 to whisky. In the 8 controls no or only a modest increase in S-iCT occurred following pentagastrin, calcium and whisky with no difference between the three. It is concluded that pentagastrin is the most useful stimulative agent for ICT secretion in patients with C-cell neoplasms. In selected cases the additional use of calcium could be advantageous.