Long-term follow up of pediatric thyroid papillary carcinoma with lung metastasis

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 622-631-Pediatric Endocrinology: Thyroid
Clinical
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-627
Yoo-Mi Kim, Ja-Hye Kim*, Jin-Ho Choi, Beom Hee Lee and Han-Wook Yoo
Asan Medical Center Children's Hospital, Seoul, South Korea
Purpose: Papillary thyroid carcinoma (PTC) is a common form of thyroid cancer, but only 1.4% of all pediatric malignancies. Children with pulmonary metastases seem to be difficult to render free from disease after surgery and radioactive iodine (RAI) therapy. Neck ultrasonography (US) and serum thyroglubulin (Tg) measurements are useful for screening of recurrence. This study investigated the trend of serum Tg levels, changes of pulmonary lesions, and prognosis in PTC pediatric patients with pulmonary metastases.

Methods: Six patients (3 males and 3 females) with PTC and pulmonary metastases diagnosed before 15 years of age were included. The relapse of PTC with pulmonary metastases were screened by neck US, chest computed tomography (CT), basal serum Tg level and I131 whole body scan. In addition, levels of Tg antibody were measured every follow-up work up. The clinical course and radiologic findings were reviewed retrospectively.

Results: The mean age at diagnosis was 10.1 years (range, 3.9-16.5 years). All patients presented with thyroid mass. Thyroid function test showed euthyroid state before surgery. CT and radio-iodine scan of lung demonstrated multiple metastatic nodules in both lobes of lung, requiring total thyroidectomy with lymph node dissection and radioactive iodine (RAI) therapy in all patients. The mean level of serum Tg at diagnosis was 207.16 ng/mL (range, 42.8-379 ng/mL). One patient had elevated anti Tg antibody resulting in falsely normal level of Tg. The mean duration of follow-up was 9.3 years (range, 3-18yr) and the mean duration of follow up after cessation of RAI was 5.6 years (range, 2-12yr). The mean dosage and frequency of RAI was 4.17 mCi/kg and 4.5 times per each patient. The average accumulated dose of RAI was 651.7 mCi. One boy and one girl experienced relapse of PTC after total thyroidectomy and initial RAI therapy. At cessation of RAI therapy, 4 out of 5 had a improving Tg level (median, 19.15 ng/mL, range 1-40.6) and their mean level of serum Tg was continuously decreasing to 11.8 ng/mL (range, 0.9-34.8 ng/mL) at the end of follow up. Only one girl who has slightly increased size of pulmonary metastasis in chest CT with still high serum Tg level. Although cessation of RAI thearpy, Tg level in 4 patients showed a decline of about 38.4% and pulmonary lesions were stable. All patients are healthy and are doing well with stable lung lesions. No late complications of RAI have been observed.

Conclusion: Continuous decline of serum Tg level was observed several years after RAI therapy with persistent stable pulmonary lesions. It may indicate the long term effects of RAI on PTC with lung metastasis in children. Long-term follow-up in large cohort of patients with PTC and pulmonary metastases should be needed to delineate clinical course and prognosis.

Nothing to Disclose: YMK, JHK, JHC, BHL, HWY

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