Follicular thyroid cancer surgery

Surgery is the mainstay of treatment for follicular thyroid cancer.

• Surgical intervention is not recommended for the management of follicular thyroid cancer.^[1]
• Surgical intervention for the management of follicular thyroid cancer varies depending on the degree of tumor invasion. It includes:
  • Total thyroidectomy
  • Lobectomy plus isthmusectomy

• Lobectomy plus isthmusectomy is indicated when the tumor is minimally invasive.^[1]
• Total thyroidectomy is indicated when the tumor is:
  • Invasive (extensive vascular invasion is present)
  • Metastatic
• Patients’preference is another indication.
• Unilateral hemithyroidectomy is uncommon due to the aggressive nature of follicular thyroid cancer.^[2]
• Total thyroidectomy is the mainstay of treatment for follicular thyroid cancer. This is invariably followed by radioiodine treatment at levels from 50 to 200 millicuries following two weeks of a low iodine diet (LID). Occasionally treatment must be repeated if annual scans indicate remaining cancerous tissue.^[3]

• The objective of surgery is to completely remove the primary tumor while minimizing treatment-related morbidity and to guide postoperative treatment with radioactive iodine (RAI). The goal of radioactive iodine (RAI) is to ablate the remnant thyroid tissue to improve the specificity of thyroglobulin assays, which allows the detection of persistent disease by follow-up whole-body scanning. For patients undergoing radioactive iodine (RAI), removal of all normal thyroid tissue is an important surgical objective. Additionally, for accurate long-term surveillance, radioactive iodine (RAI) whole-body scanning and measurement of serum thyroglobulin are affected by residual, normal thyroid tissue, and in these situations, near-total or total thyroidectomy is required. This approach facilitates follow-up thyroid scanning.

• Lobectomy is associated with a lower incidence of complications, but approximately 5% to 10% of patients will have a recurrence in the thyroid following lobectomy. Patients younger than 45 years will have the longest follow-up period and the greatest opportunity for recurrence. Follicular thyroid cancer commonly metastasizes to lungs and bone; with a remnant lobe in place, use of I-131 as ablative therapy is compromised. Abnormal regional lymph nodes should be biopsied at the time of surgery. Recognized nodal involvement should be removed at initial surgery, but selective node removal can be performed, and radical neck dissection is usually not required. This results in a decreased recurrence rate but has not been shown to improve survival.
• Following the surgical procedure, patients should receive postoperative treatment with exogenous thyroid hormone in doses sufficient to suppress thyroid-stimulating hormone (TSH); studies have shown a decreased incidence of recurrence when thyroid-stimulating hormone is suppressed.

• Total thyroidectomy and removal of involved lymph nodes or other sites of extrathyroid disease.
• I-131 ablation following total thyroidectomy if the tumor demonstrates uptake of this isotope.
• External-beam radiation therapy if I-131 uptake is minimal.

• The most common sites of metastases are lymph nodes, lung, and bone. Treatment of lymph node metastases alone are often curative. Treatment of distant metastases is usually not curative but may produce significant palliation.

• For lymph node metastasis, central neck dissection is recommended.
• Central neck dissection includes the evacuation of fibrofatty and nodal tissue from the common carotid artery to hyoid bones superiorly and inferiorly up to the innominate artery.
• Modified neck dissection is reserved for lymph nodes with macroscopic metastasis. In this procedure, all nodal and fibrofatty tissues are removed from levels II to level V in the neck.

• Spine stabilization is reserved for bone metastasis with neurologic symptoms.
• Percutaneous vertebroplasty is also recommended for bone metastasis.