Background: Thyroid carcinoma is the most common endocrine malignancy and most common secondary malignancy for childhood cancer survivors. Radiation exposure has been clearly linked to risk. Thyroid nodules in children have a high risk for malignancy, whether arising spontaneously or after radiation. Reported incidence of thyroid carcinoma after radiation is 20 times the population risk, partly due to improved long-term childhood cancer survival and more active surveillance. Despite metastatic disease being common, survival rate is high.
Objective and hypotheses: To review a series of patients with thyroid carcinoma seen over 25 years.
Method: Retrospective case note review of all thyroid carcinoma diagnosed from 1989 to 2014 in children, adolescents and those adults who had a history of childhood radiation exposure.
Results: Forty-six patients were identified. Thirty-nine (84.8%) had papillary thyroid carcinoma, 5 (10.9%) follicular carcinoma, and 2 (4.3%) medullary thyroid carcinoma (MEN2B). Thirty-three had childhood radiation exposure (17 females) with thyroid malignancy occurring 637 years later. Thyroid cancer prior to 16 years was seen in 10 (21.7%) without radiation exposure. Smallest nodule size was 4 mm. A patient with multiple nodules 78 mm had multifocal papillary carcinoma with invasion into adjacent skeletal muscle and blood vessel. Total thyroidectomy was performed for all. Central node clearance with first surgery commenced in 2005, after several late metastases occurred. Diagnostic rTSH stimulated 123I scan was performed for all, with ablative 131I if any uptake was seen. Fourteen patients had metastases: to lymph nodes (14), lungs (3), skeletal muscle (2), and bone (1). Twenty-four (52.2%) had 131I four requiring multiple courses. Forty-four are alive and tumour free. For medullary carcinoma, one continues treatment and one died.
Conclusions: Ultrasound screening is required for early diagnosis as small nodule size is not predictive of benign histology or absence of metastases. Central node clearance provides better outcome. Despite metastatic disease at presentation in some, prognosis is favourable.
01 Oct 2015 - 03 Oct 2015