Patients treated for differentiated thyroid cancer should be followed carefully with physical examinations, serum quantitative thyroglobulin levels, and radiologic studies based on individual risk for recurrent disease. Approximately 10% to 30% of patients thought to be disease free after initial treatment will develop recurrence and/or metastases. Of these patients, approximately 80% develop recurrence with disease in the neck alone, and 20% develop recurrence with distant metastases. The most common site of distant metastasis is the lung. In a single series of 289 patients who developed recurrences after initial surgery, 16% died of cancer at a median time of 5 years following recurrence.
The prognosis for patients with clinically detectable recurrences is generally poor, regardless of cell type. Those patients who recur with local or regional tumor detected only by I131 scan, however, have a better prognosis. The selection of further treatment depends on many factors, including cell type, uptake of I131, prior treatment, site of recurrence, and individual patient considerations. Surgery with or without I131 ablation can be useful in controlling local recurrences, regional node metastases, or, occasionally, metastases at other localized sites. Approximately 50% of the patients operated on for recurrent tumors can be rendered free of disease with a second operation. Local and regional recurrences detected by I131 scan and not clinically apparent can be treated with I131 ablation and have an excellent prognosis.
Purpose of This Summary
This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the formal ranking system used by the PDQ Editorial Boards to assess evidence supporting the use of specific interventions or approaches. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.
Up to 25% of recurrences and metastases from well-differentiated thyroid cancer may not show I131 uptake. For these patients, other imaging techniques shown to be of value include imaging with thallium-201, magnetic resonance imaging, and pentavalent dimercaptosuccinic acid. When recurrent disease does not concentrate I131, external-beam or intraoperative radiation therapy can be useful in controlling symptoms related to local tumor recurrences. Systemic chemotherapy can be considered. Chemotherapy has been reported to produce occasional objective responses, usually of short duration.[4,9]
A phase II study (NCT00654238) looked at the activity of sorafenib, an orally active, multityrosine kinase inhibitor that affects tumor cell proliferation and angiogenesis, administered to 30 patients with advanced iodine-refractory thyroid cancer. Among 25 assessable patients, there were 7 patients with partial responses and 16 patients with stable disease. The progression-free survival for differentiated thyroid cancer patients was 84 weeks.[Level of evidence: 3iiDiii] Further investigation of this approach is warranted.