Long-Term Effects of Radioiodine Treatment on Female Fertility in Survivors of Childhood Differentiated Thyroid Carcinoma

Background: Differentiated thyroid carcinoma (DTC) during childhood is a rare disease. Its excellent survival rate requires a focus on possible long-term adverse effects. This study aimed to evaluate fertility in female survivors of childhood DTC by assessing various reproductive characteristics combined with anti-Mullerian hormone (AMH) levels (a marker of ovarian reserve). Methods: Female survivors of childhood DTC, diagnosed at <= 18 years of age between 1970 and 2013, were included. Survivors were excluded when follow-up time was less than five years or if they developed other malignancies before or after diagnosis of DTC. Survivors filled out a questionnaire regarding reproductive characteristics (e.g., age at menarche and menopause, pregnancies, pregnancy outcomes, need for assisted reproductive therapy). Survivors aged Results: Fifty-six survivors with a median age of 31.0 (interquartile range, IQR, 25.1-39.6) years were evaluated after a median follow-up of 15.4 (IQR 8.3-24.7) years. The median cumulative dose of I-131 administered was 7.4 (IQR 3.7-13.0) GBq/200.0 (IQR 100.0-350.0) mCi. Twenty-five of the 55 survivors aged 18 years or older during evaluation reported 64 pregnancies, 45 of which resulted in live birth. Of these 55, 10.9% visited a fertility clinic. None of the survivors reported premature menopause. Age at AMH evaluation did not differ between DTC survivors and the comparison group (p = 0.268). Median AMH levels did not differ between DTC survivors and the comparison group [2.0 (IQR 1.0-3.7) mu g/L vs. 1.6 (IQR 0.6-3.1) mu g/L, respectively, p = 0.244]. The cumulative dose of I-131 was not associated with AMH levels in DTC survivors (r(s) = 0.210, p = 0.130). Conclusions: Female survivors of DTC who received I-131 treatment during childhood do not appear to have major abnormalities in reproductive characteristics nor in predictors of ovarian failure.