title: Radioactive Iodine Therapy Did Not Significantly Increase the Incidence and Recurrence of Subsequent Breast Cancer.
abstract: BACKGROUND
  Previous studies on the extent to which radioactive iodine (RAI) therapy for thyroid cancer increases the risk of subsequently developing breast cancer have given conflicting results.
  
  
  OBJECTIVE
  This study aimed to evaluate the effect of RAI treatment on breast cancer development and recurrence among female patients with primary thyroid cancer.
  
  
  METHODS
  This was a retrospective cohort study. The risk of subsequent breast cancer associated with RAI and its dose in hazard ratios (HRs) with 95% confidential intervals (CIs) were calculated using time-dependent Cox proportional hazard models.
  
  
  METHODS
  A total of 6150 patients with thyroid cancer enrolled between 1973 and 2009 were followed until December 2012. Of these, 3631 (59.0%) received RAI therapy. During the follow-up period, 99 primary breast cancers were diagnosed.
  
  
  METHODS
  Risk of breast cancer development according to RAI therapy and RAI dose during treatment for primary thyroid cancer.
  
  
  RESULTS
  RAI therapy did not significantly increase the incidence of subsequent breast cancer among female patients (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.22-1.06) when a 2-year latency period was accounted for. High-dose RAI (≥120 mCi) was associated with a reduced incidence of subsequent breast cancer (HR, 0.17; 95% CI, 0.05-0.62) in the cohort with a 2-year latency period.
  
  
  CONCLUSIONS
  The long-term follow-up results of this study suggest that RAI treatment for patients with thyroid cancer may not increase the risk or recurrence of breast cancer.
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Hwa Young
authors.initials: HY
authors.lastname: Ahn
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Hye Sook
authors.initials: HS
authors.lastname: Min
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Yohwan
authors.initials: Y
authors.lastname: Yeo
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Ma
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Yunji
authors.initials: Y
authors.lastname: Hwang
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Jee Hyun
authors.initials: JH
authors.lastname: An
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Hoon Sung
authors.initials: HS
authors.lastname: Choi
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Bhumsuk
authors.initials: B
authors.lastname: Keam
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Seock-Ah
authors.initials: SA
authors.lastname: Im
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Do Joon
authors.initials: DJ
authors.lastname: Park
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: In Ae
authors.initials: IA
authors.lastname: Park
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Dong-Young
authors.initials: DY
authors.lastname: Noh
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Yeo-Kyu
authors.initials: YK
authors.lastname: Youn
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: June-Key
authors.initials: JK
authors.lastname: Chung
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Bo Youn
authors.initials: BY
authors.lastname: Cho
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Sue K
authors.initials: SK
authors.lastname: Park
authors.affiliation: Departments of Internal Medicine (H.Y.A., J.H.A., H.S.C., B.K., S.-A.I., D.J.P., Y.J.P.), Pathology (H.S.M., I.A.E.), Preventive Medicine (Y.Y., S.H.M., Y.H., S.K.P.), Surgery (D.-Y.N., Y.-K.Y.), and Nuclear Medicine (J.-K.C.), Seoul National University College of Medicine, Seoul, Republic of Korea 110-744; Department of Internal Medicine (H.Y.A.), Seoul National University Bundang Hospital, Seongnam, Republic of Korea 463-707; Department of Internal Medicine (H.Y.A., B.Y.C.), Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea 156-755; Department of Biomedical Science (Y.H., S.K.P.), Seoul National University Graduate School, Seoul, Republic of Korea 110-744; Cancer Research Institute (Y.H., D.-Y.N., S.K.P.), Seoul National University, Seoul, Republic of Korea 110-744; and Department of Internal Medicine (H.S.C.), Kangwon National University School of Medicine, Chuncheon, Republic of Korea 200-722.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Park
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007457:Iodine Radioisotopes / Q000009:adverse effects*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology* / Q000209:etiology*; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000532:radiotherapy
chemical_list: D007457:Iodine Radioisotopes