From the Guidelines
Distant metastases of papillary thyroid carcinoma (PTC) should be managed with a multimodal approach, including total thyroidectomy, radioactive iodine (RAI) therapy, and targeted therapies such as lenvatinib or sorafenib for RAI-refractory disease, with the goal of achieving complete remission in one-third of patients with distant disease. The management of distant metastases of PTC typically involves a combination of treatments, including surgery, RAI therapy, and targeted therapies. According to the ESMO clinical recommendations 1, patients with evidence of persistent disease or detectable levels of serum Tg increasing with time require imaging techniques for the localization of disease and appropriate treatment, including therapeutic doses of 131 I. Some key points to consider in the management of distant metastases of PTC include:
- The use of RAI therapy, which can be effective in treating small-sized lung metastases that take up radioiodine 1
- The role of external beam radiotherapy in treating symptomatic bone metastases or brain lesions 1
- The use of targeted therapies such as lenvatinib or sorafenib for RAI-refractory disease, which can target the MAPK pathway frequently dysregulated in PTC
- The importance of TSH suppression therapy with levothyroxine, aiming for TSH levels below 0.1 mIU/L in high-risk patients 1
- Regular monitoring with thyroglobulin measurements, neck ultrasound, and whole-body scans every 6-12 months, with additional cross-sectional imaging as needed.
From the Research
Distant Metastases in Papillary Thyroid Cancer
- Distant metastases are a significant predictor of poor outcomes in patients with papillary thyroid cancer (PTC) 2.
- However, some patients with distant metastases may have a more favorable prognosis, with slower-growing metastases and longer survival rates 3, 2.
- Factors that predict a worse prognosis in patients with distant metastases include older age, metastases involving sites other than the lung, larger metastases, and poorly differentiated components in the primary tumor 2.
- Local operative control of PTC is important, even in patients with distant metastases, as it can improve survival rates and reduce the risk of local recurrence 2.
Treatment and Management
- Radioactive iodine (RAI) therapy is a common treatment approach for patients with PTC and distant metastases 4, 5.
- The response to RAI therapy can be predicted by factors such as serum thyroglobulin levels, locoregional involvement, and the presence of distant metastases 5.
- Multiple RAI treatments may be associated with an excellent response in some patients, although the overall response rate is relatively low 5.
- The use of RAI therapy has been shown to improve relative survival rates in patients with PTC, particularly in those with high-risk disease or larger tumor sizes 6.
Prognosis and Survival
- The prognosis for patients with PTC and distant metastases varies depending on factors such as age, histology, and the site of metastasis 4.
- Younger patients with papillary tumors and iodine-avid disease tend to have a better prognosis, with higher survival rates and longer disease-free periods 4.
- The 3-year and 5-year actuarial survival rates for patients with PTC and distant metastases are approximately 69% and 50%, respectively 4.
- Overall, the management of distant metastases in PTC requires a multidisciplinary approach, taking into account the individual patient's disease characteristics, treatment options, and prognosis 3, 2, 4, 5, 6.