Diagnosis, treatment, and follow-up of medullary thyroid carcinoma: recommendations by the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism.
BACKGROUND
Medullary thyroid carcinoma (MTC) originates in the thyroid parafollicular cells and represents 3-4% of the malignant neoplasms that affect this gland. Approximately 25% of these cases are hereditary due to activating mutations in the REarranged during Transfection (RET) proto-oncogene. The course of MTC is indolent, and survival rates depend on the tumor stage at diagnosis. The present article describes clinical evidence-based guidelines for the diagnosis, treatment, and follow-up of MTC.


OBJECTIVE
The aim of the consensus described herein, which was elaborated by Brazilian experts and sponsored by the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism, was to discuss the diagnosis, treatment, and follow-up of individuals with MTC in accordance with the latest evidence reported in the literature.


METHODS
After clinical questions were elaborated, the available literature was initially surveyed for evidence in the MedLine-PubMed database, followed by the Embase and Scientific Electronic Library Online/Latin American and Caribbean Health Science Literature (SciELO/Lilacs) databases. The strength of evidence was assessed according to the Oxford classification of evidence levels, which is based on study design, and the best evidence available for each question was selected.


RESULTS
Eleven questions corresponded to MTC diagnosis, 8 corresponded to its surgical treatment, and 13 corresponded to follow-up, for a total of 32 recommendations. The present article discusses the clinical and molecular diagnosis, initial surgical treatment, and postoperative management of MTC, as well as the therapeutic options for metastatic disease.


CONCLUSIONS
MTC should be suspected in individuals who present with thyroid nodules and family histories of MTC, associations with pheochromocytoma and hyperparathyroidism, and/or typical phenotypic characteristics such as ganglioneuromatosis and Marfanoid habitus. Fine-needle nodule aspiration, serum calcitonin measurements, and anatomical-pathological examinations are useful for diagnostic confirmation. Surgery represents the only curative therapeutic strategy. The therapeutic options for metastatic disease remain limited and are restricted to disease control. Judicious postoperative assessments that focus on the identification of residual or recurrent disease are of paramount importance when defining the follow-up and later therapeutic management strategies.
Unidade de Tireoide, Serviço de Endocrinologia, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil.
Ana Luiza
AL
Maia
Unidade de Tireoide, Serviço de Endocrinologia, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil.
Debora R
DR
Siqueira
Universidade de São Paulo, São Paulo, SP, Brasil.
Marco A V
MA
Kulcsar
Departamento de Cirurgia, Universidade Estadual de Campinas, Campinas, SP, Brasil.
Alfio J
AJ
Tincani
Faculdade de Medicina de Botucatu, Universidade Estadual Paulista Júlio de Mesquita Filho, Botucatu, SP, Brasil.
Glaucia M F S
GM
Mazeto
Divisão de Endocrinologia, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
Lea M Z
LM
Maciel
D000310:Adrenal Gland Neoplasms / Q000175:diagnosis / Q000378:metabolism / Q000628:therapy; D015415:Biomarkers / Q000032:analysis; D014408:Biomarkers, Tumor / Q000097:blood*; D044963:Biopsy, Fine-Needle; D001938:Brazil; D002116:Calcitonin / Q000097:blood* / Q000378:metabolism; D018276:Carcinoma, Medullary / Q000175:diagnosis* / Q000556:secondary / Q000628:therapy*; D018278:Carcinoma, Neuroendocrine; D003937:Diagnosis, Differential; D019317:Evidence-Based Medicine / Q000379:methods; D005192:Family Health; D005500:Follow-Up Studies; D006801:Humans; D009154:Mutation; D010673:Pheochromocytoma / Q000175:diagnosis / Q000378:metabolism / Q000628:therapy; D011379:Prognosis; D000090063:Proto-Oncogene Mas; D051096:Proto-Oncogene Proteins c-ret / Q000235:genetics; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000556:secondary / Q000628:therapy*; D016606:Thyroid Nodule / Q000175:diagnosis / Q000601:surgery; D013965:Thyroidectomy / Q000379:methods
D015415:Biomarkers; D014408:Biomarkers, Tumor; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D002116:Calcitonin; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human