Characteristics of differentiated thyroid carcinoma in children and adolescents with respect to age, gender, and histology

Abstract

BACKGROUND. Because of its rarity there have been only a few detailed studies on differentiated thyroid carcinoma (DTC) in children. The current investigation was undertaken to assess the characteristics of DTC with respect to age, gender, and histology in children and adolescents. METHODS. In a questionnaire-based survey, data from 114 children and adolescents with DTC (age range, 3-18 years) was collected from 65 clinical institutions in Germany. Characteristics of 80 females and 34 males were evaluated and the influence of age, gender, histology, multicentric growth, tumor stage, and lymph node involvement on distant metastases was tested using multivariate discriminant analysis. Comparison between groups was performed using the Student's t test and chi-square test. Correlation between incidence and age was assessed by linear regression analysis. RESULTS. The overall incidence of thyroid carcinoma in females was higher than in males, with a peak of female/male ratio occurring at puberty. The incidence of DTC correlated with age in females < 16 years (correlation coefficient [r] = 0.84; P = 0.0006), which was more pronounced in children with papillary thyroid carcinoma (PTC) (r = 0.83; P = 0.006) but not in those with follicular thyroid carcinoma (FTC) (r = 0.20; P = 0.16). FTC was associated with less advanced disease (P = 0.009), fewer lymph nodes involved (P = 0.007), and fewer metastases (P = 0.02) compared with PTC. Males tended to have a higher risk for distant metastases. However, statistical analysis failed to reach a level of significance (P = 0.08). Multivariate analysis revealed tumor stage as the only powerful factor (P = 0.02) correlated with distant metastasis. CONCLUSIONS. The incidence of PTC shows a marked increase in females with the highest female/male ratio occurring at puberty. Childhood thyroid carcinoma frequently is associated with lymph node involvement, distant metastases, and extrathyroidal tumor infiltration. In children FTC appears to be less aggressive than PTC. Advanced local-regional extension stage appears to be the most powerful factor influencing the risk for distant metastases in children.