From the Guidelines
Thyroid cancer treatment should prioritize surgical removal of part or all of the thyroid (thyroidectomy), often followed by radioactive iodine therapy to destroy any remaining cancer cells, and lifelong thyroid hormone replacement therapy with levothyroxine to replace the hormone and suppress TSH to prevent cancer recurrence, as recommended by the most recent guidelines 1.
Diagnosis and Treatment
The diagnosis of thyroid cancer typically involves thyroid ultrasound (US) supplemented by fine needle aspiration cytology (FNAC) as a first-line diagnostic procedure, with serum calcitonin (CT) measurement being a reliable tool for the diagnosis of medullary thyroid cancer 1.
- The initial treatment of differentiated thyroid carcinoma (DTC) should always be preceded by careful exploration of the neck by US to assess the status of lymph node chains.
- Total or near-total thyroidectomy is the initial treatment for DTC, whenever the diagnosis is made before surgery and the nodule is ≥1 cm, or regardless of the size and histology if there is metastatic, multifocal or familial DTC.
- Radioactive iodine therapy is used to ablate any remnant thyroid tissue and potential microscopic residual tumor, with the dose and administration method depending on the patient's risk factors and disease characteristics.
Follow-up and Monitoring
Regular monitoring with blood tests, ultrasounds, and sometimes whole-body scans is essential for detecting recurrence, with the frequency and type of monitoring depending on the patient's risk factors and disease characteristics 1.
- Thyroid function tests (FT3, FT4, TSH) should be carried out to check the adequacy of LT4 suppressive therapy, followed by screening with physical examination, neck US, and basal and rhTSH-stimulated serum thyroglobulin measurement with or without diagnostic WBS.
- The subsequent follow-up of patients considered free of disease consists of physical examination, basal serum Tg measurement on LT4 therapy, and neck US once per year.
Advanced Disease
For patients with locally recurrent, advanced, and/or metastatic DTCs that are not surgically resectable, are not amenable to radioactive iodine (RAI), and are progressing and/or symptomatic, systemic therapy can be considered, including novel treatments such as lenvatinib, vandetanib, cabozantinib, and pazopanib, sorafenib, sunitinib, axitinib, everolimus, among others 1.
- The clinical use of predictive markers is currently limited for advanced thyroid cancers, but recent data have shown that the BRAF inhibitors vemurafenib and dabrafenib can be effective treatment options for DTC harboring the BRAF V600E mutation.
From the FDA Drug Label
LENVIMA is indicated for the treatment of adult patients with locally recurrent or metastatic, progressive, radioactive iodine-refractory differentiated thyroid cancer (DTC). LENVIMA is used by itself to treat differentiated thyroid cancer (DTC), a type of thyroid cancer that can no longer be treated with radioactive iodine and is progressing
Thyroid Cancer Treatment: Lenvatinib (PO) is indicated for the treatment of adult patients with locally recurrent or metastatic, progressive, radioactive iodine-refractory differentiated thyroid cancer (DTC) 2. It is used to treat DTC that can no longer be treated with radioactive iodine and is progressing 2.
- Key Points:
- Lenvatinib is used to treat locally recurrent or metastatic DTC
- It is used for radioactive iodine-refractory DTC
- Lenvatinib is used by itself to treat DTC that can no longer be treated with radioactive iodine and is progressing 2
From the Research
Overview of Thyroid Cancer
- Thyroid cancer is expected to be diagnosed in approximately 43,720 new cases in the US in 2023, with a 5-year relative survival rate of approximately 98.5% 3.
- The most common type of thyroid cancer is papillary thyroid cancer, accounting for approximately 84% of all thyroid cancers 3.
Diagnosis and Management
- Most cases of well-differentiated thyroid cancer are asymptomatic and detected during physical examination or incidentally found on diagnostic imaging studies 3.
- For microcarcinomas (≤1 cm), observation without surgical resection can be considered, while for tumors larger than 1 cm with or without lymph node metastases, surgery with or without radioactive iodine is curative in most cases 3.
- Surgical resection is the preferred approach for patients with recurrent locoregional disease, and for metastatic disease, surgical resection or stereotactic body irradiation is favored over systemic therapy 3.
Treatment Options
- Antiangiogenic multikinase inhibitors (e.g., sorafenib, lenvatinib, cabozantinib) are approved for thyroid cancer that does not respond to radioactive iodine, with response rates of 12% to 65% 3.
- Targeted therapies such as dabrafenib and selpercatinib are directed to genetic mutations (BRAF, RET, NTRK, MEK) that give rise to thyroid cancer and are used in patients with advanced thyroid carcinoma 3.
Preoperative Evaluation
- A thorough preoperative evaluation is critical for formulating an appropriate treatment strategy in the management of thyroid cancer 4.
- The preoperative evaluation should include initial clinical evaluation, imaging modalities, cytologic evaluation, and the evolving role of mutational testing 4.
Response to Therapy Assessment
- The American Thyroid Association (ATA) guidelines recommend response to therapy (RTT) assessment 1-2 years after initial treatment in differentiated thyroid cancer (DTC) patients to guide thyrotropin (TSH) goals and long-term follow-up 5.
- The addition of stimulated-Tg adds little prognostic information in patients with no evidence of disease during the first 2 years of follow-up, and excellent RTT can be based on basal Tg together with TxWBS and structural imaging studies 5.
Fine-Needle Aspiration Biopsy
- Fine-needle aspiration biopsy is widely used for thyroid nodule evaluation, and repeated aspiration biopsies are needed due to plausible false-negative results 6.
- Ultrasound-guided fine-needle aspiration biopsy of thyroid bed lesions is accurate and efficient in triaging patients who require post-thyroidectomy follow-up for recurrent thyroid carcinoma 7.