Long-term outcome of patients with differentiated thyroid carcinoma: effect of therapy.

OBJECTIVE: To present an overview of current therapeutic practices and results in patients with differentiated thyroid carcinoma.
METHODS: Personal series of patients and selected studies reported in the literature are reviewed relative to outcome (tumor recurrence and cancer-related mortality) after treatment of differentiated thyroid cancer.
RESULTS: In the United States, thyroid carcinoma ranks 14th in incidence among the major malignant tumors. Although many factors influence the long-term outcome with papillary and follicular thyroid carcinoma, the patient's age at the time of diagnosis, tumor stage, and initial treatment are the most important. The risk of death from thyroid cancer becomes substantially greater after age 40 years and increases dramatically after 60 years of age. Tumor recurrence is more prevalent before age 20 and after age 60 years. Delay in therapy for more than a year after initial manifestation also has been shown to have an adverse effect on outcome. The optimal initial treatment is usually near-total thyroidectomy and surgical excision of extrathyroidal tumor, when possible. For complete ablation of residual thyroid tissue, radioactive iodine therapy is usually necessary and should be followed by thyroid hormone suppression of serum thyrotropin concentrations. A schedule of 6-month follow-up intervals is recommended, until the serum thyroglobulin is undetectable and 131I whole-body scanning shows no uptake in the neck or extrathyroidal sites.
CONCLUSION: An aggressive approach to management of differentiated thyroid carcinoma is likely to render about 90% of patients permanently free of disease.