Although wide surgical excision is the accepted treatment for thin malignant melanomas, there is reason to believe that narrower margins may be adequate. We conducted a randomized prospective study to assess the efficacy of narrow excision (excision with 1-cm margins) for primary melanomas no thicker than 2 mm. Narrow excision was performed in 305 patients, and wide excision (margins of 3 cm or more) was performed in 307 patients. The major prognostic criteria were well balanced in the two groups. The mean thickness of melanomas was 0.99 mm in the narrow-excision group and 1.02 mm in the wide-excision group. The subsequent development of metastatic disease involving regional nodes and distant organs was not different in the two groups (4.6 and 2.3 percent, respectively, in the narrow-excision group, as compared with 6.5 and 2.6 percent in the wide-excision group). Disease-free survival rates and overall survival rates (mean follow-up period, 55 months) were also similar in the two groups. Only three patients had a local recurrence as a first relapse. All had undergone narrow excision, and each had a primary melanoma with a thickness of 1 mm or more. The absence of local recurrence in the group of patients with a primary melanoma thinner than 1 mm and the very low rate of local recurrences indicate that narrow excision is a safe and effective procedure for such patients.
In 13 patients who had been thyroidectomized for medullary carcinoma (MCT), basal and pentagastrin-stimulated immunoreactive calcitonin (iCT) concentrations were measured in a peripheral vein and concomitantly in hepatic veins as well as in the superior and inferior caval veins. The basal concentrations of iCT in serum from the antecubital vein ranged from normal values (less than 0.50 micrograms/1) to grossly elevated (greater than 100 micrograms/1). Intravenous pentagastrin injections (0.5 micrograms/kg) stimulated transiently calcitonin secretion in all patients and peak concentrations occurred in peripheral venous blood and in the inferior caval vein after 3 to 5 minutes. In all patients peak iCT values in the hepatic vein occurred at 1 to 2 minutes and were much higher than in samples taken from other veins. Only three patients showed metastases to liver as judged by conventional clinical and laboratory examinations. Two patients with nonthyroid, malignant disease did not show an increase in serum iCT concentration of hepatic veins. The authors conclude that MCT may spread early to the liver. The presence of liver metastases is an important prognostic factor in patient evaluation and can be demonstrated by measuring iCT in hepatic veins before and during pentagastrin stimulation.
An ultrastructural study, both morphological and immunohistochemical, has been carried out on eight thyroglobulin-positive and nine thyroglobulin-negative medullary carcinomas of the thyroid. The morphometric analysis of granule size showed that all tumours contained cells with small granules and cells with medium size granules, whereas eight tumours had additional cells with large granules. The small granules had an electron dense core, while the medium and large sized granules were both pale-cored and dense-cored. The cells with small, medium or large secretory granules were all immunoreactive for calcitonin and CGRP. No ultrastructural differences were observed between thyroglobulin-positive and thyroglobulin-negative cases of medullary carcinoma of the thyroid.
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