ESPE Abstracts

Background: Thyroid cancer before 20 years of age constitutes less than 2% of thyroid malignancies. Adult guidelines have been used in evaluation and follow-up of children until 2015. Features and long-term results of more children with PTC are needed to improve the ATA guideline for children. The aim of this study is to evaluate children with PTC in the last 15 years in a single reference-center, and assess the convenience of ATA 2015 guideline in practice.

Methods: 66 cases with PTC (F/M: 48/18) are analyzed, retrospectively. Clinical features, treatment and their impact on prognosis are examined. Patients with >1.5 years follow-up were stratified for risk using the latest ATA guideline for prognosis evaluation.

Results: Median age at diagnosis was 12.2 years, and 30% were <10 years old. Multifocal, bilateral tumor, and lymph node metastases (LNM) were present in 58, 37, and 57.5% of patients, respectively. Among 38 patients with LNM, 24 (63%) had only LNM, the remaining had also local invasion and/or distant metastasis. LN and lung metastasis at diagnosis were more frequent in patients with large, bilateral and multifocal tumors. Total resection was performed in all children but one. LN dissection (LND) was performed in 68% (37% central±lateral, 31% berry picking). 8 patients underwent re-LND and 1 patient residual tumor excision after postoperative¹³¹I whole body scanning, stimulated thyroglobulin and neck ultrasound. All patients received radioactive iodine treatment (30-150 mCi). 46 patients were followed for >1.5 years, 34 (73%) were in remission, 8 (17%) had persistent and 4 (10%) had recurrent disease. 88% (15/17) with solitary tumor nodules and 65% (19/29) with multifocal tumors achieved remission (P = 0.08). Achievement of remission according to ATA 2015 risk stratification revealed that 95% (19/20) of low-risk, 62% (5/8) of moderate-risk and 55% (10/18) of high-risk went into remission, all after RAI treatment. In the low-risk group post-operative screen with RAI showed persistent local disease in 60%. Among patients with moderate/high-risk PTC, remission rate was higher in patients with solitary tumor nodule in comparison to multifocal tumor (75% vs 54%).

Conclusion: Multifocality decreases remission rate, thus it should be included in risk assessment of pediatric cases with PTC. It seems post-operative RAI screen and treatment is still crucial in achievement of remission in low-risk PTC.