Journal Article

I-131 Dose Response for Incident Thyroid Cancers in Ukraine Related to the Chornobyl Accident

O'Kane, Patrick, Bouville, Andre C., Brenner, Alina V., Hatch, Maureen, Zamotaeva, Galina A., Lubin, Jay H., Oliynik, Valery A., Zablotska, Lydia B., Ron, Elaine, Tereschenko, Valery P., Chaykovskaya, Ludmila V., Paster, Ihor P., Greenebaum, Ellen, Bogdanova, Tetyana I., McConnell, Robert J., Shpak, Victor M., Tronko, Mykola D.

2011

Overview

Background: Current knowledge about Chornobyl-related thyroid cancer risks comes from ecological studies based on grouped doses, case-control studies, and studies of prevalent cancers. Objective: To address this limitation, we evaluated the dose-response relationship for incident thyroid cancers using measurement-based individual iodine-131 (1-131) thyroid dose estimates in a prospective analytic cohort study. Methods: The cohort consists of individuals < 18 years of age on 26 April 1986 who resided in three contaminated oblasts (states) of Ukraine and underwent up to four thyroid screening examinations between 1998 and 2007 (n = 12,514). Thyroid doses of 1-131 were estimated based on individual radioactivity measurements taken within 2 months after the accident, environmental transport models, and interview data. Excess radiation risks were estimated using Poisson regression models. Results: Sixty-five incident thyroid cancers were diagnosed during the second through fourth screenings and 73,004 person-years (PY) of observation. The dose-response relationship was consistent with linearity on relative and absolute scales, although the excess relative risk (ERR) model described data better than did the excess absolute risk (EAR) model. The ERR per gray was 1.91 [95% confidence interval (CI), 0.43-6.34], and the EAR per 10⁴ PY/Gy was 2.21 (95% CI, 0.04-5.78). The ERR per gray varied significantly by oblast of residence but not by time since exposure, use of iodine prophylaxis, iodine status, sex, age, or tumor size. Conclusions: I-131-related thyroid cancer risks persisted for two decades after exposure, with no evidence of decrease during the observation period. The radiation risks, although smaller, are compatible with those of retrospective and ecological post-Chornobyl studies.

• Publisher: National Institute of Environmental Health Sciences,US Department of Health and Human Services
• Subject: Accidents / Adolescent / Adult / Age / Biological and medical sciences / Cancer / Cancer screening / Care and treatment / Chernobyl Nuclear Accident / Cohort Studies / Diagnosis / Dose response relationship / Dose-Response Relationship, Radiation / Ear / Ecological risk assessment / Ecological studies / Environment. Living conditions / Female / Health aspects / Health risks / Humans / Iodide Peroxidase - blood / Iodine / Iodine radioisotopes / Iodine Radioisotopes - toxicity / Iodine Radioisotopes - urine / Male / Medical sciences / Middle Aged / Neoplasms, Radiation-Induced - epidemiology / Neoplasms, Radiation-Induced - surgery / P values / Patient assessment / Poisson Distribution / Prophylaxis / Prospective Studies / Public health. Hygiene / Public health. Hygiene-occupational medicine / Radiation dose response relationship / Radioactive Hazard Release / Radioactivity / Radiotherapy / Risk / Risk factors / Screening / Thyroglobulin - blood / Thyroid / Thyroid cancer / Thyroid diseases / Thyroid Diseases - epidemiology / Thyroid Diseases - surgery / Thyroid Gland - radiation effects / Thyroid Gland - surgery / Thyroid Neoplasms - chemically induced / Thyroid Neoplasms - epidemiology / Thyroid Neoplasms - surgery / Thyrotropin - blood / Time Factors / Tositumomab / Toxicology / Ukraine - epidemiology / Young Adult