—-e - Sm eee x t t. t } 1 tr oe | cme * t ~ | . # ae TL Pewot ere — eeBo re ee —— a eee me ner HeByeee -- seen in animals but has been less frequently observed in human beings. aaa Eight cases of nodular goiter have been reported by Sheline et al.? in their followup study of 250 cases treated for hyperthyroidism, Six of these cases were irradiated before 20 years of age and , before 10 years of age. One case showed a possible invasion of the thyroid capsule. The incidence of thyroid nodularity in the exposed Marshallese is considerably higher than has been reported by Pincus!1 and Hempelmann}3 in their studies of populations who had been exposed to therapeutic X-irradiation of the neck region at a young age. However when comparison _ ao is made on a risk per rad basis the incidence is quite comparable with ) 7 51 cases per 10° persons per rad per year for the Marshallese and 24 cases for 1 group and 64 for a second group 108 persons per rad per year calculated by Pincus and Hempelmann, This comparison seems to indicate similar effectiveness per rad of X-radiation compared with per rad dose from radioiodine exposure. The 3 malignant lesions of the thyroid reported here- in the heavily exposed Rongelap people appear to be the first such cases clearly associated © with radioiodine exposure with the exception of the one possible malignant ~ | thyroid lesion reported by Sheline et al.? " — J ! Based on the incidence reported by the Trust Territory of carcinoma of the thyroid among the 17,000 Marshallese, the expected incidence in. the Rongelap high exposure group would be 0.056 cases over the 15 year ! period. The finding of 3 cases (5.6% incidence) thus represents a considerable increase over the expected number of cases (P>0.01, x2 test). Among.the 157 Utirik people about 0.14 cases_would be expected with 1 case reported. a - DOE ARCHIVES SY m=