Current surgical management of follicular thyroid carcinoma

Follicular thyroid carcinoma (FTC) comprises a heterogenous group of tumors, which divides into subtypes with different malignant potential: minimally invasive (excellent prognosis), encapsulated angioinvasive and widely invasive FTC (higher risk metastasis and recurrence). Numerous clinical risk factors (presence of metastases, advanced patient age, tumor size and others), which can be used to assess FTC aggressiveness, are discussed with regard to the present literature. The definitive characterization of follicular neoplasms depends on postoperative histology, due to the incapability of preoperative imaging, fine-needle aspiration cytology or molecular analysis to clearly distinguish between FTC and benign follicular thyroid adenoma. In this review, treatment strategies for FTC (according to the WHO 2017 classification of endocrine neoplasms) are presented, as recommended by the leading expert societies American Thyroid Association (ATA), British Thyroid Association (BTA), German Society of Endocrine Surgery (CAEK) and European Society of Endocrine Surgery (ESES). Hemithyroidectomy is sufficient in low-risk FTC (capsular invasion only). Thyroidectomy with postoperative radioiodine therapy is recommended for high-risk FTCs (angioinvasion; widely invasive histology). Prophylactic lymphadenectomy is not necessary. Considering clinical risk factors, an individual surgical approach should be chosen, following a stepwise, escalating surgical management with restricted primary resection (hemithyroidectomy) and, if necessary, completion surgery based on the definitive histopathology.