What is the diagnosis and treatment of papillary thyroid carcinoma (PTC)?

From the Guidelines

Papillary thyroid cancer should be treated with total or near-total thyroidectomy, followed by radioactive iodine therapy and lifelong thyroid hormone replacement therapy, as this approach has been shown to improve morbidity, mortality, and quality of life outcomes 1. The initial treatment of papillary thyroid cancer involves surgical removal of the thyroid gland, which may be partial or complete depending on the size and extent of the tumor.

• The surgery should be preceded by careful exploration of the neck by US to assess the status of lymph node chains 1.
• Less extensive surgical procedures may be accepted in the case of unifocal papillary thyroid cancer diagnosed at final histology after surgery performed for benign thyroid disorders, provided that the tumor is small, intrathyroidal, and of a favorable histological type 1.
• After surgery, radioactive iodine therapy (typically 30-100 mCi of I-131) may be recommended to destroy any remaining thyroid tissue or cancer cells 1.
• Patients will require lifelong thyroid hormone replacement therapy (levothyroxine, typically starting at 1.6-1.8 mcg/kg/day) following complete thyroidectomy 1.
• Regular follow-up is essential and includes physical examinations, thyroid function tests, thyroglobulin level monitoring, and occasional imaging studies 1.
• Papillary thyroid cancer has a favorable outcome because these cancer cells grow slowly and maintain many normal thyroid cell functions, including the ability to absorb iodine, which makes radioactive iodine treatment particularly effective 1.
• Risk factors include radiation exposure, family history, and certain genetic conditions, such as the BRAF V600E mutation, which may be targeted with specific therapies like vemurafenib and dabrafenib 1.

From the FDA Drug Label

The histological diagnoses were papillary thyroid cancer (66%) and follicular thyroid cancer (34%); of those with follicular histology, 44% had Hürthle cell and 11% had clear cell subtypes. The histological diagnoses were papillary carcinoma in 57%, follicular carcinoma (including Hürthle cell) in 25%, and poorly differentiated carcinoma in 10%, and other in 8% of the study population

Papillary Thyroid Cancer is a type of cancer that has been studied in the context of the drugs lenvatinib 2 and sorafenib 3.

• Lenvatinib has been shown to be effective in treating papillary thyroid cancer, with a statistically significant prolongation in progression-free survival (PFS) compared to placebo.
• Sorafenib has also been shown to be effective in treating papillary thyroid cancer, with a statistically significant prolongation of PFS compared to placebo. However, no statistically significant difference was seen in the final overall survival (OS) analysis for sorafenib.

From the Research

Overview of Papillary Thyroid Cancer

• Papillary thyroid cancer (PTC) is the most common thyroid malignancy, associated with an excellent prognosis and an overall survival rate of more than 90% 4.
• The first-line treatment for PTC is surgical excision, with total thyroidectomy being the preferred method for most patients 4, 5, 6.

Treatment Options

• Treatment options for PTC include:
  • Surgery (total thyroidectomy or thyroid lobectomy) 4, 5, 6
  • Radioactive iodine ablation 4, 5, 6, 7, 8
  • Thyroid hormone suppression of TSH 4, 6
  • External beam radiation (less commonly) 4
  • Chemotherapy (rarely) 4, 6
• The choice of treatment depends on patient factors, disease factors, and the decisions of the patient and treatment team 4.

Role of Radioactive Iodine

• Radioactive iodine is used for remnant ablation or treatment of residual/metastatic disease 7, 8.
• The decision and dose of radioactive iodine should be personalized and patient-specific, taking into account clinical-pathological features, risk stratification, patient preference, and institutional facilities 8.
• Selective use of radioactive iodine can increase the rate of patients with "uncertain" status during early follow-up, but the rate of structural incomplete responses remains low regardless of whether radioactive iodine is used immediately 7.

Follow-up and Monitoring

• Postoperative follow-up for PTC includes monitoring serum thyroglobulin levels and whole body radioactive iodine scans 4, 6.
• Neck ultrasound and measurement of serum thyroglobulin levels have taken the place of routine whole body radioactive iodine scans in the postoperative follow-up of patients with PTC 6.
• Recurrent locoregional cervical lymph node disease should be treated by compartmental lymph node dissection, followed by another treatment dose of radioactive iodine 6.