Table 6. Clinical Features of MEN 2 Syndromes continued...
In a randomized phase III trial for adult patients with unresectable locally advanced or metastatic hereditary or sporadic medullary thyroid carcinoma treated with vandetanib, a selective inhibitor of RET, VEGFR, and EGFR, versus placebo, vandetanib administration was associated with significant improvements in progression-free survival, response rate, disease control rates, and biochemical response.
Treatment options under clinical evaluation
The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI Web site.
- NCI-07-C-0189 (NCT00514046) (Vandetanib to Treat Children and Adolescents With Medullary Thyroid Cancer): This phase I/II NCI trial is investigating vandetanib, an orally available tyrosine kinase receptor inhibitor, for patients aged 5 to 18 years, with hereditary thyroid medullary carcinoma.[35,36]
The Carney complex is an autosomal dominant syndrome caused by mutations in the PPKAR1A gene, located in chromosome 17. The syndrome is characterized by cardiac and cutaneous myxomas, pale brown to brown lentigines, blue nevi, primary pigmented nodular adrenocortical disease causing Cushing syndrome, and a variety of endocrine and nonendocrine tumors, including pituitary adenomas, thyroid tumors, and large cell calcifying Sertoli cell tumor of the testis.[37,38,39] There are guidelines that may be followed for screening patients with Carney complex.
For patients with the Carney complex, prognosis depends on the frequency of recurrences of cardiac and skin myxomas and other tumors.
Pheochromocytoma and Paraganglioma
Pheochromocytoma and paraganglioma are rare catecholamine-producing tumors with a combined annual incidence of three cases per 1 million individuals. Tumors arising within the adrenal gland are known as pheochromocytomas, whereas morphologically identical tumors arising elsewhere are termed paragangliomas. Paragangliomas are further divided into: (1) sympathetic paragangliomas that predominantly arise from the intra-abdominal sympathetic trunk and usually produce catecholamines, and (2) parasympathetic paragangliomas that are distributed along the parasympathetic nerves of the head, neck, and mediastinum and are rarely functional.[40,41]
It is now estimated that up to 30% of all pheochromocytomas and paragangliomas are familial; several susceptibility genes have been described (see Table 7). The median age at presentation in most familial syndromes is 30 to 35 years, and up to 50% of subjects have disease by age 26 years.[42,43,44,45]