Thyroid carcinoma and its treatment.

Thyroid cancer is a rare disease. Aetiological factors are increased secretion of TSH and exposure of the growing gland to ionizing radiation. Pathological classification is in two main groups: differentiated and undifferentiated. Differentiated is subdivided into papillary, follicular and medullary. Papillary and medullary carcinomas occur in young patients, grow slowly, spread by lymphatics. Treatment is surgical excision of thyroid and affected nodes plus thyroid hormone replacement. Follicular carcinoma spreads by blood to lungs and bones. Treatment is total thyroidectomy and radioiodine therapy of the metastases followed by thyroid hormone replacement. Undifferentiated tumours occur in old patients. They are identified by drill biopsy and treated with radiotherapy.