IMPE Abstracts

Introduction: Papillary thyroid cancer represents the eighth most frequent neoplasm in pediatrics. In the Instituto Nacional de Pediatría it is the most frequent endocrine neoplasm commonly associated with other thyroid disease.

Objective: To evaluate the association between papillary thyroid cancer and risk factors such as sex, autoimmune thyroiditis, history of neoplasia and radiation.

Methods: Retrospective and analytical cohort of 53 pediatric patients with histopathological diagnosis of papillary thyroid cancer (PTC), we obtained from the clinical record information on: sex, history of neoplasia and radiation, autoimmune thyroiditis, TNM staging of thyroid cancer and its biochemical and structural response to treatment.

Results: There were 53 children with papillary thyroid cancer, 13 boys (24.5%) aged 11.1±3.5 years and 40 girls (75.5%) 13.7±2.8 years. Of these, 25 patients (47.2%) had histopathological diagnosis of concomitant autoimmune thyroiditis, 19 girls (76%), age 14.3±2.3 years and 6 boys (24%), age 11.4±2.9 years, of which 56.5% had normal thyroid profile at diagnosis. Tumor size was smaller in those with autoimmune thyroiditis (P=0.05) and was associated with less extra-thyroidal extension (P=0.01). Of all the sample (n=53), 37.7% (n=20) had positive antithyroglobulin antibodies and 34% (n=18) had positive anti peroxidase antibodies. No significant differences were observed in the characteristics of lymph node metastasis or distant metastasis between the two groups (P=0.4, P=0.09, respectively). Regarding the history of family cancer, 41.5% of the patients had a positive history. When comparing treatment response there were 4 possible outcomes (ATA criteria) between those with and without autoimmune thyroiditis: excellent response 12 vs 4, incomplete biochemical response 1 vs 4, indeterminate response 7 vs 6 and incomplete structural response 5 vs 14, respectively (P=0.02). Regarding the response to treatment, there were no statistically significant differences in the groups considering age, sex, history of neoplasia and history of radiation (P=0.34, P=0.48, P=0.18, P=0.31 respectively).

Conclusions: The presence of autoimmune thyroiditis is high (47.2%) in patients with PTC and was associated both with a lower extrathyroid extension and with a favorable response to treatment, in agreement with other series, in relation to sex, history of neoplasia and radiation, we did not observe significance for the prognosis.