Method of Endogenous TSH Stimulation in the Follow-up of Differentiated Thyroid Cancer
The treatment of differentiated thyroid cancer (DCT) includes surgery followed by
radioiodine treatment. In the follow-up of patients it is necessary to induce TSH elevation
for the measurement of thyreoglobulin and/or total body scanning. There are two principal
methods to obtain TSH elevation: 1) injection of recombinant human TSH , and 2) to stop
L-thyroxin replacement for several (3-4) weeks. As use of recombinant TSH is rather
expensive, this method is not feasible in many countries. The problem with stopping
L-thyroxin is development of severe hypothyroidism for several weeks with concomitant
symptoms and signs.
Current pilot study aims to induce the necessary TSH elevation by decreasing the L-thyroxin
dose. The main hypothesis is that necessary TSH stimulation will be achieved during 4-6
weeks in majority of patients with fixed dose of L-thyroxin. Concomitantly, blood tests and
symptoms and signs of hypothyroidism will be obtained to get information about possible
deviations during treatment with low dose of thyroxin.
Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Diagnostic
TSH level at the end of study
The percentage of patients obtaining TSH level at least 30 imU/L at the end of study period. Blood tests will be obtained after 4 weeks. If TSH > 30 the patient has completed the study. If TSH < 30 patient will continue for 1 week and blood tests will be obtained after week 5. If TSH > 30 the patient has completed the study. If TSH < 30 patient will be monitored during 1 week and blood tests will be obtained after 6 weeks.
Vallo Volke, MD, PhD
Estonia: The State Agency of Medicine