Retrospective Evaluation of Cytogenetic Effects Induced by Internal Radioiodine Exposure: A 27-Year Follow-Up Study

Abstract

Radioiodine (131I) is widely used in the treatment of hyperthyroidism and as an effective ablative therapy for differentiated thyroid cancer (DTC). Radioiodine (131I) constitutes 90% of the currently used therapies in the field of nuclear medicine. Here, we report the cytogenetic findings of a long-term follow up study of 27 years on a male patient who received two rounds of radioiodine treatment within a span of 26 months between 1992 and 1994 for his papillary thyroid cancer. A comprehensive cytogenetic follow up study utilizing Cytokinesis Blocked Micronucleus (CBMN) assay, Dicentric Chromosome Assay (DCA), genome wide translocations and inversions was initiated on this patient since the first administration of radioiodine in 1992. Frequencies of micronuclei (0.006/cell) and dicentric chromosomes (0.008/cell) detected in the current study were grossly similar to that reported earlier in 2019. The mFISH analysis detected chromosome aberrations in 8.6% of the cells in the form of both unbalanced and balanced translocations. Additionally, a clonal translocation involving chromosomes 14p; 15q was observed in 2 of the 500 cells analyzed. Out of the 500 cells examined, one cell showed a complex translocation (involving chromosomes 9, 10 and 16) besides 5 other chromosome rearrangements. Collectively, our study indicates that the past radioiodine exposure results in long lasting chromosome damage and that the persistence of translocations can be useful for both retrospective biodosimetry and for monitoring chromosome instability in the lymphocytes of radioiodine exposed individuals.

Radiation Biodosimetry: Current Status and Future Initiatives

“…The article by Satyamitra et al [2023] provides an overview of the operational aspects of the biodosimetry program by the National Institute of Allergy and Infectious Diseases (NIAID)/Radiological Nuclear Countermeasure Program (RNCP), followed by the manuscript of Aryankalayil et al [2023] on biomarkers for biodosimetry and their potential role(s) in predicting radiation injury. The special issue features three manuscripts on CBMN assay [(1) evaluation of comparative efficacy of CBMN assay in whole blood and isolated lymphocytes for triage application by Bertucci et al [2023], (2) assessment of fractionated total body radiation-induced micronuclei frequency in the peripheral blood of adult and pediatric populations by Kanagaraj et al [2023], and (3) application of CBMN for high radiation dose exposures using imaging flow cytometry by Beaton-Green et al [2023]] and three manuscripts on cytogenetic biodosimetry [(1) scoring of Calyculin-A-induced G2-premature chromosome condensation objects for dose assessment in ex-vivo irradiated human blood samples and in the blood samples of radiotherapy patients by Sun et al [2023], (2) a 27-year follow-up study on internal radioiodine-induced chromosome aberrations in a thyroid cancer survivor by Livingston et al [2023], and (3) an international comparison exercise performed at two irradiation facilities in the USA and Germany for biodosimetry after neutron exposures by Endesfelder et al [2023]]. The manuscript from the group of Dr. Lacombe [Lacombe et al, 2023] presents a paper-based vertical flow immunoassay method for the point-of-care multiplex detection of radiation dosimetry genes.…”