Radioactive iodine (RAI) therapy in thyroid cancer patients does not cause such patients to get breast cancer, suggests a retrospective study of female patients from Seoul National University Hospital in South Korea.
The study enrolled 6,150 patients with thyroid cancer between 1973 and 2009, who were followed until December 2012. Of the sample, 3.691 (59%) received RAI therapy, and 99 were diagnosed with primary breast cancers during the follow-up period.
The study showed that RAI therapy did not significantly increase the incidence of breast cancer subsequent to diagnosis of thyroid cancer among patients, when a 2-year latency period was accounted for. An additional finding was that the numbers of breast cancer diagnoses made during the follow-up period for those study participants who received high doses of RAI therapy (greater than or equal to 120 mCi) and those patients who did not receive any RAI therapy were not significantly different from each other.
“The results from our study based on a large cohort of thyroid cancer patients clearly demonstrated that RAI treatment in these patients did not increase the risk of development nor worsen the recurrence of breast cancer,” Dr. Hwa Young Ahn of the department of internal medicine at Seoul National University, South Korea, and Hye Sook Min, and associates.
Read the full study in the Journal of Clinical Endocrinology & Metabolism (doi:10.1210/JC.2014-2896).
This study was supported by research grants from the Korean Foundation for Cancer Research, Seoul National University Bundang Hospital Research Grants, and the Education and Research Encouragement Fund of Seoul National University Hospital. The investigators reported having no financial conflicts of interest.