The effect of radioiodine on eradication of Helicobacter pylori infection in patients with thyroid cancer—A pilot study

Recently, 32% of Helicobacter pylori (H pylori) infected patients who were treated for differentiated thyroid carcinoma (DTC) were found to have a negative urease breath test at 2 months posttreatment. Our objectives were to eradication of clarify equivocal findings, and determine whether radioiodine eradicates this chronic bacterial infection. Twenty-eight patients (25 DTC patients and 3 with hyperthyroidism) positive for H pylori stool antigen were treated with oral radioiodine (131I) at a dose of 100 to 200 mCi in 18 patients with thyroid carcinoma; 30 mCi in 1 patient with a significant residual mass in the thyroid bed after surgery; and 4 mCi in 6 patients who had been treated with 100 to 150 mCi over the last 5 years. The hyperthyroid patients received 10 to 20 mCi. To standardize the results, and better compare with a previous study, only those patients who received a dose of 100 to 200 mCi were included for analysis. All 18 DTC patients who tested positive for H pylori stool antigen before radioiodine treatment remained positive 3 months posttreatment, indicating an eradication rate of 0% with an upper 95% confidence limit of 18.53%. Radioiodine administered to H pylori infected patients did not eradicate infection in Israeli patients.