PET in Medullary Thyroid Cancer

Abstract

The optimal treatment for medullary thyroid cancer is total thyroidectomy and central nodal lymphadenectomy at presentation when the primary cancer is small and has not metastasized significantly (1). In the three phenotypes of familial medullary cancer, i.e., familial medullary cancer, multiple endocrine neoplasia (MEN) IIA, and MENIIB, screening of families for patients with a mutation in the RET proto-oncogene and a genetic predisposition for the diseases allows surgery at an even earlier stage (2–4). Unfortunately, not all patients are treated at the optimal time. Some patients with sporadic medullary cancer have extensive local and distant metastases at the time of diagnosis. It is important to define the extent of disease when planning treatment. Other patients who have undergone appropriate surgery are found to have a measurable calcitonin level after the operation. This implies there is residual disease in the thyroid bed or lymph nodes or distant sites. It is helpful if the site or sites of calcitonin production can be identified when they are small and amenable to removal at a reoperation.