SUN-614 Thyroid Nodules in a Cohort of Childhood Cancer Survivors: A Single Center Experience

The aim of our study was to identify patients suffering from thyroid nodules and thyroid carcinoma in a pediatric population with previous neoplasm. Patients and methods: 44 patients (23 females; 21 males) with thyroid nodules among a single center population with a previous diagnosis of hematologic or solid tumor at a mean age 7.4 ± 4.9 years were recruited. Radiotherapy was performed in 30 patients (Total body irradiation, TBI =18; locoregional radiotherapy, RT =12). The mean age at the first thyroid nodule detection was 17.2±5 years FNAB was performed in 36/44 pts. with nodules larger than 7 mm and/or suspect sonographic findings TSH, FT4 and thyroid antibodies assays were performed in all patients Results FNAB showed: 13 Tir2 (36.1%), 14 Tir3 (38,9%), 4 Tir4 (11.1%) and 5 Tir5 (13.9%). Histological finding of PTC was demonstrated in 8 of 9 patients with Tir4 and Tir5 and in 9 out of 14 pts.with Tir3 (69,2%,). after thyroidectomy and in 1 out of 9 Tir4 and Tir5 an insular tumor was diagnosed by Core Needle Biopsy . Overall, 18 thyroid carcinomas in our population (40,9%) were detected. Among patients with malignant nodules: 11/18 (61,1%) were male and 7/18 (38,9%) were female. Radiotherapy cumulative dose was 12.2±1 Gy in 14/18 malignant nodules and 22.1±15.8 Gy in 16/26 benign nodules (P=0.016) Considering only patients submitted to TBI (18): 11/18 (61%) were malignant; 7/11 of them (63.6%) were male and 4/11 (36.4%) were female. When population was grouped according to the age at the diagnosis of the first malignancy (<8 years and ≥8 years old), a longer time between previous malignancy and thyroid nodules diagnosis was showed in the younger group (10.8±3.2 years vs 8.4±5.2 years, p=0.028. Discussion. These data show that the ultrasound imaging in this population allowed to detect small size thyroid nodules, 40.9% of them were demonstrated to be thyroid carcinomas. FNAB Tyr3 cytologic reports were demonstrated to be malignant in 69.2% at histological examination; this data differs from general population. The surgical option should be considered in this high risk population in order to better plan further therapeutical strategies. TBI was associated with high risk (61%) of malignancy. Male sex was more frequently associated with thyroid carcinoma in the entire population, as well as in TBI subgroup. Lower cumulative doses of radiotherapy were associated to increased risk of thyroid malignancy, according to previous studies.