Iodine-131 administration and risk of cancer: “Appearances can be deceptive”

Recently, an interesting meta-analysis concerning the risk of cancer in patients submitted to I administration for diagnosis or therapy of benign thyroid diseases has been published by Hieu and co-workers. These authors examined seven studies including 22,029 exposed subjects in the therapeutic cohorts and 24,799 in the diagnostic cohorts, summarizing data on 64 different organs or organ group subsets. Outcome was pooled as the relative risk (RR) using both standard and bias adjusted methods. While no increase in the overall burden of cancer was observed, a higher and significant risk for kidney (RR 1.70, 95%CI: 1.15-2.51) and thyroid cancer (RR: 1.99, 95%CI: 1.22-3.26) was demonstrable in the group of patients submitted to I administration.