[Progress and controversy on the extent of surgery for medullary thyroid carcinoma based on calcitonin levels].

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor originating from the parafollicular cells (C cells) of the thyroid gland, classified as sporadic and hereditary. Calcitonin (Ctn) secreted by the C cells is a specific serological marker for MTC, which is of great value in diagnosis, treatment and postoperative management of MTC. The effect of chemoradiotherapy and 131I therapy on MTC is limited, with surgery being the primary therapy. Given the aggressive nature and relatively poor prognosis of MTC, the reasonable surgical extent is crucial for improving cure rate and prognosis of patients. However, there are still some controversies regarding the extent of surgery for MTC. This article elaborates on the research progress and controversies of serum Ctn levels in assisting the evaluation of the extent of surgery for MTC.