Thyroid Hormone Replacement After Total Thyroidectomy

Type-Specific TSH Targets

High-risk patients with differentiated thyroid cancer should have TSH suppressed to <0.1 mIU/L, according to the American Society of Clinical Oncology 1, 2, 3
Intermediate-risk patients with differentiated thyroid cancer should have a TSH target of 0.1-0.5 mIU/L, as recommended by the American Society of Clinical Oncology 2, 3
Low-risk patients with differentiated thyroid cancer and excellent response to therapy can have TSH maintained at 0.5-2.0 mIU/L, which is the normal range, as suggested by the American Society of Clinical Oncology 2, 3
In medullary thyroid cancer, TSH suppression is not appropriate because C cells lack TSH receptors, and TSH should be kept in the normal range (0.5-2.0 mIU/L) through levothyroxine dose adjustment, according to the National Comprehensive Cancer Network 4, 5, 1
For benign disease, such as goiter or thyrotoxicosis, the TSH target should be 0.5-2.0 mIU/L, which is the normal physiologic range, as recommended by the American Society of Clinical Oncology 2

The first TSH measurement should occur 6 weeks after surgery, allowing sufficient time for steady-state levels to be achieved, as suggested by the American Society of Clinical Oncology 6
TSH and free T4 should be measured at 6 weeks postoperatively, and repeat TSH every 6 weeks after each dose adjustment until target is achieved, according to the American Society of Clinical Oncology 6

In differentiated thyroid cancer patients, TSH suppression therapy provides benefit by reducing growth stimulus on potential residual tumor cells, but the degree of suppression must be risk-stratified to avoid iatrogenic thyrotoxicosis complications in low-risk patients, as recommended by the American Society of Clinical Oncology 1, 2, 3