ESPE Abstracts

Background: Papillary thyroid cancer (PTC) constitutes more than 90% of the thyroid cancer in children. PTC behaves differently in prepubertal children than in pubertal children and between children and adults. BRAF gene activating mutations lead to PTC by creating aberrant activation. The most common mutation is BRAF^V600E.

Objective and hypotheses: To evaluate clinicopathological characteristics of PTC patients with emphasis on the pubertal status and investigate association of BRAFV600E mutation with disease characteristics.

Method: Medical records of 75 patients with PTC were reviewed retrospectively. BRAF^V600E mutation status was found in medical records of 56 patients.

Results: Mean age at diagnosis was 12.4±3.8 years. There was no difference in sex, symptoms and tumor histopathology between prepubertal and pubertal children. BRAF^V600E mutation was similar. Although prepubertal children had greater tumor size, there was no difference in pathological evidence of tumor aggressiveness. Lymph node and lung metastasis were more prevalent in prepubertal children. Prepubertal children needed at a greater frequency lateral neck dissection (P=0.043) and more frequently treated with second or more dose of radioactive iodine (P=0.048). Persistent disease or recurrence were more frequent in prepubertal children (P=0.02). BRAF^V600E mutation was found in 14(25%) patients and was high in classic variant PTC (P=0.024). It was similar in girls and boys (P=0.7), and in tumors larger than 1 cm or smaller than 1 cm (P=0.7). Multicentrisite was high in BRAF^V600E mutation (P=0.01) but lymphovascular invasion, perineural invasion, thyroid capsular invasion, extrathyroidal invasion of the tumor were similar. There was no relation between BRAF^V600E mutation and lymph node and pulmonary metastasis at diagnosis.

Conclusion: PTC is more aggressive in prepubertal children. BRAF^V600E mutation is not correlated with a more extensive or aggressive disease. Presence of the BRAF^V600E mutation is not the cause of the differences in the biological behaviour PTC in prepubertal and pubertal children.