Endocrine Abstracts

Introduction: Treatment options for progressive metastatic unresectable medullary thyroid carcinoma (MTC) include tyrosine kinase inhibitors (TKIs) or somatostatin analogues (SSA), although the efficacy of the latter is debatable. In such cases, combined treatment of TKIs and SSAs has not previously been reported.

Aim: To present a metastatic MTC case successfully treated with a combination of Vandetanib and Lanreotide Autogel.

Case report: A 67-year-old patient presented with progressively exacerbated anorexia, 40 kg weight loss and chronic diarrhoea. Abdominal CT scan demonstrated a hilus hepatic mass of 5.4 cm and multiple hepatic metastases. Hepatic biopsy revealed a well-differentiated neuroendocrine tumour. Octreoscan showed increased uptake in the liver and left thyroid lobe. Neck/chest CT scan revealed a mass of 4.46 cm in the left thyroid lobe. One month later, upon referred to our department, abdomen MRI showed enlargement of the hilus hepatic mass up to 10.5 cm and multiple hepatic metastatic lesions the greater of which 11 cm, located in the right lobe, suggesting rapid progression of the disease. Thyroid FNA confirmed an MTC. Calcitonin (60 300 pg/ml) and CEA (851 μg/l) levels were elevated. Based on hormonal, radiological and cytological findings an unrespectable rapidly progressive metastatic MTC was diagnosed. Given the rapid progression of disease combination treatment with Lanreotide Autogel 120 mg s.c. monthly and Vandetanib 300 mg daily was initiated, hoping to hamper further progression. In view of the possible synergic action of the above-mentioned drugs on QTc prolongation, the patient was kept under close electrocardiographic monitoring. No signs of QTc prolongation were marked. The patient experienced rapid remission of the diarrhoeic syndrome and shrinkage of the thyroid mass, which became almost impalpable within 4 weeks. Six months later, a new Abdomen MRI and neck/chest CT showed a significant shrinkage in size and number of the above-mentioned lesions. No new lesions were observed. The majority of hepatic metastases was non-measurable, the metastatic hilum mass became 4.5 cm and the thyroid mass 2.9 cm. Overall tumour burden reduced >30% according to RECIST criteria. Calcitonin levels fell to 125 pg/ml, while CEA unexpectedly elevated to 1528.5 μg/l, regardless of clinical and radiological remission. No adverse effects requiring dose adjustment were observed.

Conclusions: Combination of Vandetanib and Lanreotide Autogel could be considered as a safe and effective treatment for metastatic, rapidly progressive, unresectable MTC. Further studies comparing combination treatment to Vandetanib monotherapy are needed to validate the efficacy of this approach.