Endocrine Abstracts

Vandetenib has been used as novel treatment of locally invasive medullary carcinoma of thyroid. We report the use of Vandetenib in a paediatric patient with inoperable medullary carcinoma of thyroid gland. Our patient presented to the dental surgeons at age 12 years with tongue and lip swellings. Biopsy demonstrated mucosal neuromas suggestive of MEN2B. He was clinically euthyroid but had a firm goitre. Ultrasound showed a large heterogenous thyroid mass encasing the common carotid artery. CT angiography showed heterogenously enhancing enlarged left thyroid lobe surrounding the left common carotid artery and displacing the trachea, with multiple lung nodules suggestive of metastatic involvement. Genetic analysis confirmed MEN2B [heterozygous for c.2753T>C (p.Met918Thr)] as a result of new mutation. Calcitonin15400 ng/l (normal <15) and carcinoembryonic antigen (CEA)153 μg/l (normal <5) were high. The lesion was deemed inoperable due to its size and proximity to the common carotid artery, together with a very high risk of stroke. A trial of Vandetenib at a dose of 100 mg daily was started. This was tolerated well with only transient photosensitive skin reaction.The calcitonin level fell down to 1200 ng/ml in 2 months and a repeat CT scan showed reduction in size of the primary thyroid malignancy, lymph nodes and pulmonary metastases. In an open label phase 2 study, Vandetanib 300 mg daily has shown a partial response in 20% of the patients and an additional 53% had stable disease lasting at least 24 months. The serum calcitonin and CEA levels decreased by at least 50% from baseline for at least 4 weeks in 80% and 53% patients respectively. The reported adverse effects include prolonged QT interval and photosensitive rashes. To our knowledge this is the first attempt at treating metastatic medullary thyroid carcinoma (MEN2B) with Vandetenib in a paediatric patient in the UK and the intial response appears to be promising.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.