Long-term management of differentiated thyroid cancer.

The surveillance and long-term management of patients with differentiated thyroid cancer are highly dependent upon the individual patient's risk for recurrent disease. A 30-year-old woman who presents with a 1-cm intrathyroidal papillary cancer requires minimal surveillance following primary therapy: yearly examinations and thyroglobulin measurements on L-thyroxine suppressive therapy, periodic chest radiographs, and initially, periodic neck ultrasound examinations if the right equipment is available. These should be sufficient to identify the unexpected neck or distant recurrence. A 65-year-old man who presents with a 4-cm follicular cancer invading the thyroid capsule and intrathyroidal blood vessels needs more extensive surveillance. In addition to chest radiographs, neck ultrasound studies, and serum thyroglobulin measurements while the patient is off L-thyroxine therapy, total-body 131I scanning should be done 12 months after remnant ablation, and even if no uptake is demonstrated, 131I scanning should be repeated at 24 or 60 months. Any patient who presents with grossly invasive or metastatic disease should be treated aggressively. If feasible, aggressive surgical treatment of recurrent disease is optimal and may be curative. 131I scanning and treatment may be repeated at 6- to 12-month intervals for slow-growing functional metastases. Rapidly growing metastases should be treated by external beam radiotherapy, which can follow surgical debulking, or be combined with radioiodine or chemotherapy. Unfortunately, chemotherapy is of limited value in late metastatic disease, however, rarely it results in prolonged remission.