Medullary thyroid carcinoma (MTC) arises from parafollicular C cells. What is the most sensitive marker for monitoring disease recurrence after total thyroidectomy for MTC?
- A Serum thyroglobulin
- B Serum calcitonin ✓
- C Carcinoembryonic antigen (CEA)
- D Serum chromogranin A
Correct answer: B. Serum calcitonin
Explanation
Calcitonin is the specific tumor marker for medullary thyroid carcinoma and is the most sensitive marker for both initial diagnosis and postoperative surveillance. Normalization of calcitonin after surgery indicates biochemical cure. CEA is also secreted by MTC cells and its level correlates inversely with differentiation—a rapidly rising CEA with stable calcitonin suggests dedifferentiation. Thyroglobulin is only relevant for follicular-derived thyroid cancers. Chromogranin A is used for neuroendocrine tumors generally but is less specific for MTC.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.