Thyroid Cancer After Diagnostic Doses of Iodine-131: A Retrospective Cohort Study

摘要: The incidence of thyroid cancer was evaluated in 35,074 patients examined for suspected disorders between 1951 and 1969 with an average 1.92 megabecquerel ((MBq) 52 microCi) 131I. radiation dose to the gland was, on average, approximately 0.5 Gy. mean age at time examination 44 years; 5% were under 20. Patients followed 20 years. Record linkage Swedish Cancer Register identified 50 cancers occurring 5 years or more after initial 131I examination, contrast 39.4 expected based general population rates (standardized ratio (SIR) = 1.27, 95% confidence interval 0.94-1.67). Risk highest among males (SIR 2.70, n 10), 5-9 2.22, 23), receiving than 74 microCi 2.74 MBq 2.04, 17). However, these observations confounded by fact that a tumor received exposures overall risk 2.77, 34). given reasons other not increased =more » 0.62, 16). anticipated be risk, i.e., women 1.12, 40) those observed 10 0.93, 27), showed no evidence response. Overall, data provide little proof is carcinogenic humans support notion potential internal beta particles might as low four times less external x rays gamma rays.« less