Assessment of thyroid cancer risk associated with radiation dose from personal diagnostic examinations in a cohort study of US radiologic technologists, followed 1983–2014

Abstract

ObjectiveTo assess whether personal medical diagnostic procedures over life, but particularly those associated with exposure in adulthood, were associated with increased thyroid cancer risk.DesignParticipants from the US Radiologic Technologists Study, a large, prospective cohort, were followed from the date of first mailed questionnaire survey completed during 1983–1989 to the earliest date of self-reported diagnosis of thyroid cancer or of any other cancer than non-melanoma skin cancer (NMSC) in any of three subsequent questionnaires up to the last in 2012–2014.SettingUS nationwide, occupational cohort.ParticipantsUS radiologic technologists with exclusion of: those who reported a previous cancer apart from NMSC on the first questionnaire; those who reported a cancer with an unknown date of diagnosis on any of the questionnaires; and those who did not respond to both the first questionnaire and at least one subsequent questionnaire.Primary outcome measureWe used Cox proportional hazards models with age as timescale to compute HRs and 95% CI for thyroid cancer in relation to cumulative 5-year lagged diagnostic thyroid dose.ResultsThere were 414 self-reported thyroid cancers (n=275 papillary) in a cohort of 76 415 persons. Cumulative thyroid dose was non-significantly positively associated with total (excess relative risk/Gy=2.29 (95% CI −0.91 to 7.01, p=0.19)) and papillary thyroid cancer (excess relative risk/Gy=4.15 (95% CI −0.39, 11.27, p=0.08)) risk. These associations were not modified by age at, or time since, exposure and were independent of occupational exposure.ConclusionOur study provides weak evidence that thyroid dose from diagnostic radiation procedures over the whole of life, in particular associated with exposure in adulthood, influences adult thyroid cancer risk.

Role of DNA Repair Variants and Diagnostic Radiology Exams in Differentiated Thyroid Cancer Risk: A Pooled Analysis of Two Case–Control Studies

“…Compared to the latest publication on the US radiologic technologist cohort, including 90,305 radiologic technologists in the U.S. who were followed during 1983-1998, the values of our coefficients for thyroid radiation doses received during childhood are slightly higher than the coefficients estimated in the general analysis and the papillary carcinoma sub-analysis (32). Our estimates are also slightly higher than estimates in both the most recent analysis among Japanese atomic-bomb survivors(12) and the IARC study of the highly contaminated area of Belarus following the Chernobyl nuclear accident (8).…”

Radiation and Second Primary Thyroid Cancer Following Index Head and Neck Cancer

“…If secondary thyroid cancer is the best‐known case of incidentalomas, there could be the possibility that some indolent or very early stage cases are also incidentally treated while patients are receiving radiation treatment for primary HNC or other therapeutic radiation use, and thus, these cases are never discovered or reported. For example, two recent studies examining long‐term occupational radiation exposure among dental professionals found no significance between radiation exposure and developing thyroid cancers . Future studies are needed to examine this hypothesis.…”

“…For example, two recent studies examining long-term occupational radiation exposure among dental professionals found no significance between radiation exposure and developing thyroid cancers. 33,34 Future studies are needed to examine this hypothesis.…”

Association between functional polymorphisms in the flanking region of miR-143/145 and risk of papillary thyroid carcinoma

“…[ 1 ] Papillary thyroid carcinoma (PTC), accounting for more than 80% of thyroid cancer, has been sharply increasing in recent years. [ 2 , 3 ] Although the etiology of PTC is not well clarified, some risk factors have been demonstrated to contribute to the tumorigenesis of PTC, such as ionizing radiation, [ 4 ] obesity, [ 5 , 6 ] smoking, [ 6 ] hormonal exposures [ 7 ] as well as environmental pollutants. [ 8 ] However, not all individuals develop PTC even though exposure to the same risk factors, indicating other factors, such as genetic variants may be involved in the pathogenesis of PTC.…”