Endocrine Abstracts

Introduction: Differentiated thyroid cancer accounts for 1.5% of all pediatric malignancies. Papillary thyroid cancer (PTC) is the most common subtype and is associated with more advanced disease at diagnosis compared to adults. The aim of this study was to identify long-term outcomes of pediatric PTC.

Methods: Records of 30 patients with PTC diagnosed in childhood and adolescence and followed up at Istanbul Faculty of Medicine were reviewed retrospectively.

Results: The mean age of 30 patients (21 females, 9 males) at diagnosis was 14,7±2,4 years (range, 7 to 18). Mean duration of follow-up was 126,8±45,2 months. Five patients had history of radiation therapy (RT); mean duration from RT to diagnosis of PTC was 7,2±2,4 years. Mean nodule diameter was 1,54±1,32 cm, and fine-needle aspiration biopsy was Bethesda II in 6,6%, III in 6,6%, IV in 10%, V in 26,6%, and VI in 46,6%. The patients underwent total thyroidectomy (n=9), or total thyroidectomy with central lymph node dissection (n=9) or total thyroidectomy with central and lateral lymph node dissection (n=12). The tumor was located in both lobes in 43,3% of the patients, in left lobe in 30%, in right lobe in 20%, and in isthmus in 3.3%. The mean tumor diameter was 1,56±1,47 cm (range, 0,1 to 6), and was microcarcinoma in 12 of the patients. Histopathological subtype was available in 28 patients (follicular variant n=13, classic n=9, encapsulated follicular n=3, tall cell n=1, macrofollicular n=1, hobnail n=1, diffuse sclerosing n=1). Chronic lymphocytic thyroiditis was detected in 10 patients. Six patients had BRAF mutation. There were 5 patients with T2 and 2 patients with T3 disease. At diagnosis, half of the patients had lymph node metastasis to the neck or upper mediastinum (N1a=5, N1b=10), and 2 also had lung metastasis. Of 10 patients with N1b, 7 had multicentric disease and vascular invasion, and 6 had lymphatic invasion. Eight low-risk patients still in remission were treated with only TSH-suppressive levothyroxine. Post-operative radioactive iodine (RAI) treatment was administered to 22 patients [median number of administration was one (range 1-7), median cumulative dose was 150 mCi (range 50 to 1100)]. Sixteen patients had excellent response following single (n=13) or multiple (2 for persistent and 1 for recurring disease after 100 months) RAI administrations. Remaining 3 patients had structural incomplete and 3 had indeterminate response.

Conclusions: Although PTC presented at more advanced stage in childhood and adolescence, the response to treatment was fairly good with appropriate management.