ANALYSIS OF THE FACTORS CONDITIONING THE CLINICAL COURSE OF DIFFERENTIATED THYROID CARCINOMA IN CHILDREN AND YOUNG ADULTS

Objectives: aim of this study was to ascertain for the first time whether characteristics of differentiated thyroid carcinoma (DTC) may significantly vary according to age, even within a peculiar study population covering only young patients aged less than 30 years. Methods: the population was composed by 64 patients (47 females) aged <30.0-yrs at diagnosis of DTC (mean age 22.9 ± 5.5 yrs). The main clinical, biochemical and pathologic data at DTC diagnosis were retrospectively recorded in 2 selected cohorts including, respectively, 19 patients aged less than 18 years (Group A) or 45 young adults aged between 20 and 29.8 years (Group B). Results: The distribution of DTC cases in the different age ranges progressively increased with age. Both groups had a higher proportion of females, indeed the female: male ratio was 2.6:1 and 2.75:1 in Group A and B respectively. Group A exhibited at diagnosis a more severe clinical involvement and a higher rate of extra-regional metastases. Moreover, the association with autoimmune thyroid diseases (AITDs) and biochemical thyroid dysfunction was also more common in Group A (p = 0.02 and p = 0.007 respectively). The age at DTC diagnosis correlated with the tumor size at pathology evaluation (r = –0.27, p < 0.05) but not with US nodule diameter, TSH and fT4 serum levels. Thyroid dysfunction at DTC diagnosis was associated more frequently with multifocality (p = 0.02), metastasis (p = 0.004) and recurrence (p = 0.0005) and needed also more radiotherapy cycles (p = 0.006) if compared with euthyroid DTC patients. Thyroid nodules were smaller in patients with AITDs in comparison to those without AITDs (p = 0.006). Moreover, multifocality of DTC required more cycles of therapy (p = 0.02). During the whole follow-up time, the overall survival rate was 100%, but 11.1% in Group A and 4.5% in Group B were alive with persistent residual TC. Conclusions: In a study population younger than 30 years: a) the risk of developing DTC increases with age, achieving its zenith during the 3rd decade of life; b) clinical presentation is more severe in children and adolescents younger than 18 years than in the patients aged between 20 and 30; c) in the cohort of children and adolescents DTC is more often associated with AITDs, which might play some role in conditioning the more aggressive phenotypical presentation of DTC in this patient group. A close US follow-up in children and adolescents with thyroid dysfunction, ATD and/or thyroid nodules is needed and indicated to earlier diagnosis of a thyroid malignancy.