Strategies for thyrotropin use to monitor patients with treated thyroid carcinoma

Detection of residual and recurrent thyroid carcinoma requires long-term monitoring of patients with serum thyroglobulin measurement and radioiodine scanning during temporary thyrotropin (TSH) stimulation. Recombinant thyrotropin (rTSH) permits these studies to be performed without the morbidity associated with withdrawal of thyroid hormone therapy. A protocol for rTSH use is proposed, beginning with measurement of serum thyroglobulin during TSH suppression. Patients at significant risk of recurrence with a low initial thyroglobulin level then have rTSH stimulation testing. Patients with positive rTSH-stimulated thyroglobulin concentrations and/or radioiodine scans can then be directed for appropriate therapy. The previously studied 2-dose rTSH protocol with imaging at 48 hours after 131I dosing requires Monday-through-Friday testing in most settings, but new regimens may be established. rTSH-stimulated testing may be less accurate in patients with thyroglobulin autoantibodies and those with residual normal thyroid tissue, and is generally unnecessary when there is other evidence of residual disease. Physicians should consider patients' pretest probability of disease in deciding whether and how often to perform rTSH-stimulated testing after primary treatment for thyroid carcinoma.