Twenty-five years after chernobyl: outcome of radioiodine treatment in children and adolescents with very high-risk radiation-induced differentiated thyroid carcinoma.
Reiners C, Biko J, Haenscheid H, Hebestreit H, Kirinjuk S, Baranowski O, Marlowe RJ, Demidchik E, Drozd V, Demidchik Y. J Clin Endocrinol Metab. 2013 Jul;98(7):3039-48. PMID:23616148
After severe reactor emergencies with release of radioactive iodine, elevated thyroid cancer risk in children and adolescents is considered the main health consequence for the population exposed.: We studied thyroid cancer outcome after 11.3 years' median follow-up in a selected, very high-risk cohort, 234 Chernobyl-exposed Belarusian children and adolescents undergoing postsurgical radioiodine therapy (RIT) in Germany
Cumulatively 100 children with or (without; n = 134) distant metastasis received a median 4 (2) RITs and 16.9 (6.6) GBq (with=457mCi, without=178mCi), corresponding to 368 (141) MBq/kg iodine-131. Of 229 patients evaluable for outcome, 147 (64.2%) attained complete remission [negative iodine-131 whole-body scan and TSH-stimulated serum thyroglobulin (Tg) < 1 μg /L], 69 (30.1%) showed nearly complete remission (complete response, except stimulated Tg 1-10 μg/L), and 11 (4.8%) had partial remission (Tg > 10 μg/L, decrease from baseline in radioiodine uptake intensity in ≥ 1 focus, in tumor volume or in Tg). Except for 2 recurrences (0.9%) after partial remission, no recurrences, progression, or disease-specific mortality were noted. One patient died of lung fibrosis 17.5 years after therapy, 2 of apparently thyroid cancer-unrelated causes. The only RIT side effect observed was pulmonary fibrosis in 5 of 69 patients (7.2%) with disseminated lung metastases undergoing intensive pulmonary surveillance.
Conclusions: Experience of a large, very high-risk pediatric cohort with radiation-induced differentiated thyroid carcinoma suggests that even when such disease is advanced and initially suboptimally treated, response to subsequent RIT and final outcomes are mostly favorable.
COMMENT-This study reports a very favorable outcome with average 11year follow-up in a (selected) group of children with higher-risk disease (97% N1 and 43% M1). To date only 3 of 234 died of the tumor or disease-related treatment. It will be of great interest to review the outcome in another decade, especially among those with probable radiation-related pulmonary fibrosis. L De Groot, MD
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