Assessment of Female Fertility and Carcinogenesis After Iodine-131 Therapy for Differentiated Thyroid Carcinoma

The aim of this study was to evaluate female fertility, carcinogenic, and genetic effects after treatment with {sup 131}I of differentiated thyroid carcinoma. A total of 814 females of child-bearing age were studied. The fertility of 627 females who received {sup 131}I therapy was compared to 187 untreated females. Birth histories of the children born from these women were registered. The carcinogenic effect was evaluated by comparing the incidence of tumors in 730 patients treated with {sup 131}I with an internal control group, as well as with local population incidence. There was no significant difference in the fertility rate, birth weight and prematurity between the two groups. Only one case of a ventricular septal defect was observed in a child born to a woman treated with {sup 131}I. The overall standardized incidence ratio (SIR) of second tumors was 1.19 (95% CI: 0.76-1.77) in patients treated with {sup 131}I. An elevated SIR was registered for salivary gland tumors and melanoma. No case of leukemia was registered. The risk of long-term effects of {sup 131}I treatment of differentiated thyroid carcinoma is quite low. Iodine-131 may be safely used in treating cases with a high risk of recurrence. 35 refs., 7 tabs.