1st-order laboratory parameters-obligatory laboratory tests.
- TSH, T3, T4 (usually euthyroid; possibly hyperthyroidism in differentiated follicular and papillary carcinomas).
- Tumor markers:
- Medullary thyroid carcinoma (C-cell carcinoma; medullary thyroid cancer, MTC): calcitonin, carcinoembryonic antigen (CEA). RET oncogene in familial formsNote: In addition to MTC, an elevation in serum calcitonin can be C-cell hyperplasia, renal insufficiency (process leading to a slowly progressive reduction in renal function), primary hyperparathyroidism (pHPT; primary disease of the parathyroid glands with increased production of parathyroid hormone and resulting hypercalcemia (calcium excess)), or in very rare cases, a neuroendocrine tumor (NET). A stimulation test with injection of pentagastrin or calcium is indicated for low or borderline elevated calcitonin levels.
- Carcinomas of the follicular epithelium:
- Anaplastic carcinomas: no tumor markers.
- Follicular and papillary carcinomas: thyroglobulin (Tg) and thyroglobulin-AK (Tg-AK).
Laboratory parameters 2nd order – depending on the results of the history, physical examination and mandatory laboratory parameters – for differential diagnostic clarification or follow-up.
- Gene analysis in suspected medullary thyroid carcinoma – exclusion of MEN (multiple endocrine neoplasia) by analysis for RET protooncogene.
- Follow-up:
- TSH basal (every 3 months until target TSH is reached, then every 6-12 months), FT3, FT4,
- Thyroglobulin (if below detection limit: Tg after rTSH stimulation* ) + Tg-AK; detection after thyroidectomy (thyroidectomy) suggests metastases (daughter tumors).
- Postoperatively and every 6-12 months; calcitonin (medullary thyroid carcinoma; C-cell carcinoma; MTC); if necessary, also CEA – semi-annually, after 5 years: annually.
* Genetically engineered rTSH (ThyrogenR) for thyroglobulin determination in the follow-up of carcinoma patients who have undergone surgery and radioiodine therapy.