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

 The Italian Society of Anatomic Pathology and Cytology (SIAPEC) classification for malignancy of thyroid nodules was found to be highly accurate among 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 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).

Of all nodules assessed, 26 were malignant, equating to a 13% rate of malignancy. Among only nodules greater than 1 cm in diameter, the rate of malignancy was 26%.

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

Stratified by malignancy, benign nodules were more likely to be located in the left lobe (P =.01), to be smaller (mean diameter, 8 vs 24 mm; P <.0001), to not involve lymph nodes (P <.0001), to have intranodal vascularity (P =.003), and to have intranodal calcification (P =.009).

The patients received periodical 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), indeterminate risk (TIR3a; n=14; TIR3b; n=9), or high risk (TIR4: n=3; TIR5: n=16).

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

The 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 among an independent cohort of pediatric patients.

The study authors concluded that the SIAPEC classification system for malignancy of thyroid nodules was accurate at determining both malignant and benign thyroid nodules among 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