From the Guidelines
Patients with distant metastases of papillary thyroid cancer (PTC) should receive 100–200 mCi (3.7–7.4 GBq) of 131 I after TSH stimulation, as this approach has been shown to improve outcomes in terms of morbidity, mortality, and quality of life 1.
Management of Distal Metastases
The management of distal metastases of PTC typically involves a multimodal approach, including:
- Total thyroidectomy with neck dissection
- Radioactive iodine (RAI) therapy at doses of 100-200 mCi
- TSH suppression therapy with levothyroxine
RAI-Refractory Cases
For RAI-refractory cases, targeted therapies such as lenvatinib or sorafenib may be recommended, as they have shown efficacy in improving outcomes in patients with advanced disease 1.
Monitoring and Prognosis
Regular monitoring with thyroglobulin levels, neck ultrasound, and whole-body scans is essential to assess disease progression and response to therapy. Prognosis varies based on patient age, tumor burden, and RAI avidity, with 5-year survival rates ranging from 25-50% for patients with distant metastases 1.
Quality of Life
Despite distant metastases, PTC generally maintains a more favorable prognosis compared to other metastatic cancers due to its typically slow growth and responsiveness to therapy in many cases. The goal of treatment should be to improve quality of life, reduce morbidity, and prolong survival, while minimizing the risk of adverse effects from therapy 1.
From the Research
Distal Metastases of Papillary Thyroid Cancer (PTC)
- Distal metastases in PTC are a significant predictor of poor outcomes, with a 5-year disease-specific survival rate of 65% and a 10-year rate of 45% 2
- The presence of distant metastases is the most important predictive factor of poor outcomes in patients with PTC 2
- Treatment options for distal metastases include surgery, external-beam radiotherapy, radioactive iodine (RAI) therapy, and kinase inhibitors for progressive iodine-refractory disease 3, 4, 5
Treatment Approaches
- Radical resection, including extensive neck dissection and extended resection of involved organs, can be an effective approach for locally advanced neoplasms, even in the presence of distant metastases 2
- Sorafenib, a kinase inhibitor, has been shown to improve progression-free survival in patients with radioactive iodine-refractory, locally advanced or metastatic differentiated thyroid cancer 6
- RAI therapy can be effective for treating avid cervical and pulmonary disease, and can be used in combination with other treatments such as surgery and thyroid-stimulating hormone (TSH) suppression 3, 4, 5
Prognostic Factors
- Older age at the time of distant metastases detection, distant metastases involving sites other than the lung, and presence of large nodal metastases are predictive of worse prognosis 2
- The size of the distant metastases, with diameters ≥2 cm, is also a predictive factor of worse prognosis 2
- The presence of poorly differentiated components in the primary neoplasm is also a predictive factor of worse prognosis 2