Accuracy of Italian Classification Strategy for Predicting Malignancy of Pediatric Thyroid Nodules

The Italian Society of Anatomic Pathology and Cytology (SIAPEC) classification for thyroid nodule malignancy was found to be highly accurate in a pediatric population, according to findings from a retrospective study published in Endocrine.

All pediatric patients (N=200) with thyroid nodules larger than 0.5 cm treated at the Regina Margherita Children’s Hospital in Italy between 2000 and 2020 were retrospectively evaluated by the SIAPEC classification strategy for determining malignancy.

The patient cohort included 119 girls and the mean age at diagnosis was 11.6 years (range, 2-18).

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Of all nodules assessed, 26 were malignant, corresponding to 13% malignancy. Only nodules greater than 1 cm in diameter had a malignancy rate of 26%.

A family history of autoimmune thyroid disease was reported by 53.9% of participants and 34.6% of pediatric patients had been diagnosed with autoimmune thyroid disease. Few patients had been previously exposed to radiotherapy for cancer (14.1%) and no risk factors were identified in 17.3% of the participants.

Stratified by malignancy, benign nodules were more likely to be located in the left lobe (P = 0.01), were smaller (mean diameter, 8 vs 24 mm; P < 0.0001), not to involve lymph nodes (P < .0001), to have intranodal vascularity (P = .003), and to have intranodal calcification (P = .009).

Patients received periodic clinical and ultrasound evaluations (n=125) and underwent fine needle aspiration biopsy (n=49) and surgery (n=14).

During fine needle aspiration biopsy, the nodules were categorized as low risk (TIR1: n=7; TIR1C: n=4; TIR2: n=22), undetermined risk (TIR3a; n=14; TIR3b; n=9) or high risk (TIR4: n=3; TIR5: n=16).

During surgery, malignancy was found in 77.8% of TIR3b, 100% of TIR4 and 100% of TIR5 nodules.

Accuracy for all nodules was 95% and there was 100% accuracy for low-risk and high-risk categories. For indeterminate categories, the accuracy was 100% for TIR3a and 77.8% for TIR3b nodules.

This study was underpowered; in addition, the SIAPEC classification strategy should be confirmed by an independent cohort of pediatric patients.

The study authors concluded that the SIAPEC classification system for thyroid nodule malignancy was accurate in determining both malignant and benign thyroid nodules in children.

Reference

Tuli G, Munarin J, Agosto E, et al. Predictive factors of malignancy in pediatric patients with thyroid nodules and performance of the Italian classification (SIAPEC 2014) in the outcome of the cytological FNA categories. endocrine. Published online June 14, 2021. doi:10.1007/s12020-021-02784-0

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