Trial Information

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.