Recurrent Metastatic Medullary Thyroid Carcinoma: A Case of Sustained Response to Prolonged Treatment with Somatostatin Analogues

Background: Medullary thyroid carcinoma (MTC) is a rare disease. Treatment options for recurrent disease are limited. Although somatostatin analogues might have a role as anticancer agents in MTC, the evidence is inconclusive. Patient Findings: A 64-year-old male was diagnosed with MTC in January 2010. Total thyroidectomy with neck dissection (stage IVA, pT2pN1bM0, R1) was performed, followed by adjuvant locoregional radiotherapy. Two years later, in January 2012, the patient developed recurrent metastatic disease, evidenced by elevated carcinoembryonic antigen (CEA) and calcitonin levels, and a positive uptake (Octreoscan (R)) in the right adrenal gland and pancreatic head. A further computed tomography (CT) scan revealed metastases in the right adrenal gland, the duodenal bulb, and two pancreatic lesions, which were later confirmed as metastases by endoscopic ultrasound and cytology, and therefore salvage surgery was ruled out. Treatment with Somatuline Autogel (R) (120 mg subcutaneously every 28 days) was initiated in September 2012, and 11 months later, calcitonin and CEA levels had both normalized, and a new CT scan showed that the metastatic lesions had disappeared or shrunk markedly. An Octreoscan performed in January 2014 and a repeat contrast-enhanced CT in February 2014 showed sustained tumor response. The patient remained in remission until February 2016, when a new Octreoscan revealed recurrent disease in the right adrenal gland, a nodule in the right upper pulmonary lobe, and nodal disease in the celiac trunk. CEA and calcitonin levels remained normal, although with a slight increase in calcitonin levels (47 pg/mL). Summary: The unusual case is described of a patient with metastatic MTC involving the adrenal gland, duodenum, and pancreas, who achieved a sustained response to somatostatin analogues after 11 months of treatment. The patient remained in remission for nearly 3.5 years from initiation of treatment with somatostatin analogues. Conclusions: The case presented here is one of the few described in the literature in which long-term treatment with somatostatin analogues resulted in a sustained tumor response in a patient with metastatic recurrent MTC following curative-intent surgery. These findings suggest that prolonged treatment with somatostatin analogues may be beneficial in asymptomatic cases with a low tumor burden and a positive Octreoscan following recurrence. More data are needed to confirm these findings.