Medullary thyroid cancer (MTC) accounts for about 3% to 5% of thyroid cancers, is more malignant than papillary cancer, and has a higher probability of metastasis and recurrence. Surgery is the main treatment modality, and radiotherapy and chemotherapy are not effective.
Surgery
Surgical resection is the only treatment modality that has a proven efficacy. The surgical option is usually total thyroidectomy with prophylactic central lymph node dissection.
Postoperative radioactive iodine (RAI) therapy is usually not required unless the lesion contains elements of differentiated thyroid cancer (papillary or follicular carcinoma).
Postoperatively, regular review is needed to draw blood to monitor serum carcinoembryonic antigen (CEA, a common tumor marker) and calcitonin (CT) levels, both of which help monitor for tumor recurrence.
About 15% to 25% of MTC is inherited, called hereditary MTC, so doctors recommend that all children of people with medullary carcinoma be genetically screened, and if a child or adolescent is found to carry the disease-causing mutation but does not develop the disease temporarily, a prophylactic resection may be considered, followed by a lifetime of thyroid hormone pills (such as “eugenol”). The first step in the process is to take a thyroid hormone pill (e.g., “Eugenol”) for life.
Other treatments
External radiation therapy (“radiotherapy”) and chemotherapy are not effective, and radiotherapy of metastases is considered only in the presence of brain or spinal cord metastases, and chemotherapy alone or in combination with multiple drugs is not recommended.
In addition, two targeted drugs – vandetanib and cabozantinib – have been approved in the United States for the treatment of advanced medullary carcinoma, and another drug, soventinib, is still in clinical trials. However, no targeted drugs for medullary-like cancer have been marketed in China.
Co-written by Dr. Weibo Xu, Cancer Hospital of Fudan University