Indications for Thyroidectomy
Thyroidectomy is indicated for thyroid malignancies (with extent determined by tumor characteristics), medullary thyroid carcinoma requiring total thyroidectomy, toxic nodular goiter unresponsive to medical therapy, and large goiters causing compressive symptoms or cosmetic concerns. 1
Malignant Disease: Clear Indications for Total Thyroidectomy
For differentiated thyroid cancer, total thyroidectomy is recommended when tumor size exceeds 4 cm, distant metastases are present, extrathyroidal extension exists, cervical lymph node metastases are documented, bilateral thyroid disease is present, poorly differentiated histology is found, macroscopic multifocal disease exists, aggressive variants are identified, or prior radiation exposure occurred. 1
Medullary thyroid carcinoma (MTC) with tumors ≥1 cm or bilateral disease requires total thyroidectomy with bilateral central neck dissection (level VI), as regional nodal metastases are present in over 50% at diagnosis. 1
For hereditary MTC syndromes, prophylactic total thyroidectomy timing is stratified by RET mutation risk level:
- Risk level D mutations (MEN 2B, codon 883,918, or compound heterozygous RET mutations): total thyroidectomy in the first year of life or at diagnosis 2
- Risk level B mutations (codon 609,611,618,620,630, or 634): prophylactic total thyroidectomy by age 5 years or when mutation is identified 2
- Risk level A mutations (codon 768,790,791,804,891): annual basal calcitonin testing and ultrasound; total thyroidectomy may be deferred if tests are normal, no family history of aggressive MTC exists, and family agrees 2
Poorly differentiated thyroid cancer requires total thyroidectomy with lymph node dissection due to the high rate of regional nodal metastases. 1
Anaplastic thyroid cancer requires total thyroidectomy when technically feasible, though the aggressive nature often limits surgical options. 1
Malignant Disease: When Lobectomy May Be Considered
Lobectomy plus isthmusectomy can be considered for differentiated thyroid cancer when all of the following criteria are met: no prior radiation exposure, no distant metastases, no cervical lymph node metastases, no extrathyroidal extension, tumor ≤4 cm in diameter, unifocal disease, and well-differentiated histology. 1
Even when lobectomy is technically acceptable, total thyroidectomy remains the most common choice due to lower recurrence rates and improved long-term outcomes. 1
For NIFTP (noninvasive follicular thyroid neoplasm with papillary-like nuclear features), only lobectomy is needed when margins are negative and no contralateral lesion exists. 1
Hyperthyroidism: Surgical Indications
Surgery (subtotal or near-total thyroidectomy) is indicated for hyperthyroidism when radioiodine has been refused, a large goiter causes compressive symptoms in the neck, or rapid definitive treatment is required. 3
Toxic nodular goiter causing hyperthyroidism is best treated with radioiodine as first-line therapy; surgery is reserved for patients with large goiters causing compression or when radioiodine is contraindicated. 4, 3
For Graves' disease, surgery has a limited role and is rarely used unless radioiodine has been refused or contraindicated, or a large compressive goiter is present. 3
Thyroid autonomy always requires definitive treatment, with surgery being one option alongside radioiodine. 5
Large Goiters: Indications for Surgery
For large nontoxic multinodular goiters with local compression symptoms (dysphagia, dyspnea, or tracheal deviation), surgical excision is the preferred treatment. 4
Indications for treatment in multinodular goiter include hyperthyroidism, local compression symptoms attributed to the goiter, cosmetic concerns, and suspicion of malignancy based on FNA results. 4
For small, asymptomatic nontoxic multinodular goiters with normal TSH levels and benign FNA of prominent nodules, yearly clinical observation is sufficient without surgical intervention. 4
Levothyroxine suppression therapy to decrease multinodular goiter size is controversial and often unsuccessful, with potential for adverse effects from exogenous hyperthyroidism; it should not be used in patients with suppressed TSH levels. 4
Critical Surgical Considerations
Total thyroidectomy should only be performed by surgeons experienced in endocrine surgery, as complication rates are four times higher when performed by surgeons doing fewer than 10 thyroidectomies per year compared to those performing more than 100 annually. 2
The most common significant complications are hypoparathyroidism and recurrent laryngeal nerve injury, which occur with higher frequency after total thyroidectomy. 2
In experienced hands, long-term recurrent laryngeal nerve injury occurs in approximately 3% and permanent hypoparathyroidism in 2.6% after total thyroidectomy, compared to 1.9% and 0.2% respectively after subtotal thyroidectomy. 2
Transient hypocalcemia is common (5.4% immediately post-surgery) but persists in only 0.5% of patients at 1 year when performed by experienced surgeons. 2
Referral to a surgeon and team experienced in pediatric thyroid surgery is advised for very young children given the increased risks. 2