Pulmonary fibrosis in youth treated with radioiodine for juvenile thyroid cancer and lung metastases after Chernobyl.

PURPOSE: The objective of this project was to systematically determine the prevalence and consequences of pulmonary fibrosis in youth with thyroid carcinoma and lung metastases from Belarus who were treated with radioiodine ((131)I).

METHODS: A total of 69 patients treated for juvenile thyroid carcinoma and lung metastasis with (131)I were assessed. A group of 29 patients without lung metastases and prior (131)I treatment served as controls. The assessments included a CT scan of the lungs, extensive pulmonary function testing and an incremental cycle test to volitional fatigue with measurements of oxygen uptake (VO(2)), oxygen saturation and alveolar-arterial difference in oxygen partial pressure (ΔaaO(2)).

RESULTS: Five patients with lung metastases showed advanced pulmonary fibrosis on CT scans and also had poorer lung functions compared with the 62 patients with none or minor signs of fibrosis and the 29 controls. Furthermore, these five patients showed lower peak VO(2), lower oxygen saturation at peak exercise and higher exercise ΔaaO(2). They were younger at the time of cancer diagnosis and had received chemotherapy more frequently than youth with pulmonary metastases who did not develop fibrosis. One of the five patients subsequently died from pulmonary fibrosis.

CONCLUSION: Following the Chernobyl catastrophe, about 7% of children treated with radioiodine for thyroid carcinoma and lung metastases displayed pulmonary fibrosis which was associated with functional impairments. Based on the characteristics of affected individuals, the number of radioiodine courses may have to be limited, especially in young children, and chemotherapy should be avoided.