Endocrine Abstracts

JOINT3632

Patients with medullary thyroid carcinoma (MTC) usually present with extensive regional involvement or distant metastatic disease at diagnosis or during follow-up, preventing cure by initial thyroidectomy. Treatment options in advanced CMT include surgery, radiotherapy, and tyrosine kinase inhibitors (TKIs) such as vandetanib.

Materials and Methods: We aimed to evaluate four patients with metastatic CMT treated with vandetanib followed at our level between 2021 and 2024 with a minimum follow-up of 6 months.

Results: Four patients met the inclusion criteria, 3 men and one woman. The mean age was 40 years. All four patients underwent total thyroidectomy with lymph node dissection. Metastases were to the lung, bone, cerebellum and liver. The main indication for vandetanib was progression of lung metastases. Regarding response to treatment, one patient was stable, one patient showed a partial response and 2 patients escaped treatment after 6 to 12 months of stability. The average duration of treatment was 13 months [4-19 months]. Side effects were observed in 3 patients, including hypertension, QT prolongation, diarrhea, acne and hypocalcemia. In the end, two of the patients died.

Discussion: Vandetanib targets the RET oncogene, the vascular endothelial growth factor receptor and the epidermal growth factor receptor. The use of vendetanib can cause remarkable side effects, altering patients’ quality of life, while response to treatment is not always satisfactory. Thus its prescription must take into account the benefit-risk balance and be discussed in a multidisciplinary meeting.

Conclusion: The use of vandetanib in the management of advanced CMT has led to stabilization of lesions and control of the disease for at least a certain period before escape.