Surgical management of sporadic medullary thyroid cancer

Abstract

Inherited and sporadic medullary thyroid cancer (MTC) is a rare carcinoma. Sporadic MTCs represent 70% of cases. Diagnosis is currently made with the routine use of serum calcitonin (CT) measurements to screen patients with nodular thyroid disease. Surgery is the only curative treatment of MTC and since cervical lymph nodes metastases are frequent and can occur at an early stage, a standardized lymph node dissection should be associated to total thyroidectomy. However, the extent of lymphadenectomy remains debated. Prognosis of MTC is related to both the stage of the disease and the extent of initial surgery. When tumor remnants persist after surgery, there are very few therapeutic alternatives, and these are generally of limited curative value.

How has the management of medullary thyroid carcinoma changed with the advent of 18F-FDG and non-18F-FDG PET radiopharmaceuticals

“…Furthermore, Ct can be elevated in C-cell hyperplasia, small cell lung cancer, carcinoid, chronic renal failure, and with proton pump inhibitor treatment. Although these potential falsepositive circumstances would benefit from confirmatory pentagastrin stimulation, unfortunately this test is rarely performed [3,8,11] and not approved in the USA. Infrequently, MTC is suspected because of symptoms of flushing and diarrhea, or because of family history [10].…”

“…Unfortunately, the numbers of patients in these studies are too small to form conclusions on the role of preoperative PET imaging in MTC. Preoperative 18 F-FDG PET has been suggested for Ct greater than 400 pg/ml by some authors [8], although preoperative PET or somatostatin scintigraphy has not yet been included in contemporary practice guideline recommendations [10].…”

“…Surgery is curative in 90% of MTCs in primary lesions measuring less than 10 mm but falls markedly with increasing primary lesion size, where only 50% of patients with primary lesions more than 1 cm are cured of their disease [8]. MTC metastasizes to paratracheal and lateral cervical lymph nodes in 20-30% of cases with tumor size less than 1 cm (T1), 50% with size 2-4 cm (T2), and 90% for T3-T4 tumors [1].…”

“…Management of MTC is challenging, as regional nodal (B50%) and distant metastases (up to 20%) at diagnosis are common [1,3]. Successful therapy for both sporadic and hereditary forms of MTC is dependent upon complete tumor resection; therefore, accurate preoperative staging is important [5][6][7][8]. However, unlike well-differentiated thyroid cancers, imaging and treatment with radioiodine has no role in the management of MTC.…”

Surgical Approach to the Management of Medullary Thyroid Cancer: When Is Lymph Node Dissection Needed?

“…Patients with clinically evident disease are best treated with a minimum of a total thyroidectomy and bilateral central neck dissection. Ipsilateral lateral neck dissection should be added if the primary tumor is larger than 1 cm in size or there is evidence of positive nodes in the central neck, although some surgeons advocate bilateral neck dissection for all patients with MTC, since cervical lymph node metastases are frequent and can occur at an early stage [25]. A contralateral lateral neck dissection should be considered in patients with bilateral tumors or extensive lateral adenopathy on the side of the primary tumor [21].…”