Patients with DTC are initially treated with a total thyroidectomy and radioiodine therapy. Hereafter, all patients are treated with high doses of thyroxin aiming at significantly suppressing... Show morePatients with DTC are initially treated with a total thyroidectomy and radioiodine therapy. Hereafter, all patients are treated with high doses of thyroxin aiming at significantly suppressing thyrotropin (TSH) levels, resulting in a subclinical hyperthyroid state. The rationale of this approach is based on the potential harmful effects of TSH on tumor recurrence. Furthermore, thyroxin replacement therapy can be transiently stopped in these patients to detect residual or recurrent disease by TSH stimulated thyroglobulin levels. As a result of this standardized procedure, patients become overtly hypothyroid. In this thesis, questions about the clinical consequences of exogenous subclinical hyperthyroidism and hypothyroidism on bone metabolism, glucose metabolism, the autonomic nervous system and quality of life in patients with DTC are addressed. Show less