Low doses of radiation still increase risk of leukemia, lymphoma and myeloma
A new study published in The Lancet Haematology that tracked 310,000 radiation-monitored workers showed a positive association between protracted low-dose exposure to ionizing radiation and mortality due to some hematological malignancies.[1]
The study provides crucial insights into radiation exposure’s impact on cancer risk. While this study looked specifically at low-dose exposure of employees at nuclear facilities, it has direct correlation to technologists in radiology and staff in interventional radiology and cardiology.
Researchers found a positive association between protracted low-dose exposure to ionizing radiation and mortality due to some hematological malignancies. Given the relatively low doses typically accrued by workers in this study, which amounted to 16 mGy (16 mSv) average cumulative red bone marrow dose, the radiation attributable absolute risk of leukemia mortality in this population is low. The authors said the risk was one excess death in 10,000 workers over a 35-year period.
For reference, average natural background radiation exposure is about 3 mSv per year. Patient exposure for an average chest CT scan is about 6 mSv, and a positron emission tomography–computed tomography (PET/CT) whole body protocol is about 22 mSv. The average annual dose to interventional operators in cath labs is about 3 mSv.
“Our studies of people exposed to low doses of radiation add to our understanding of radiation risks at the exposure levels encountered in many contemporary settings. Our results can inform radiation protection standards and will provide input for discussions on protections from radiation,” explained David Richardson, PhD, professor of environmental and occupational health at UC Irvine Joe C. Wen School of Population and Public Health, the principal investigator for the study, said in a statement.
The study is a major update to the International Nuclear Workers Study (INWORKS), an international epidemiological study of workers in the nuclear sector to assess their risks of cancer and non-cancerous diseases.
The researchers assembled a cohort of about 310,000 radiation-monitored workers from France, the U.K. and the U.S., employed at nuclear facilities between 1944 and 2016. Using Posson regression methods, researchers measured the amount of radiation absorbed into bone marrow. Since radiation exposure is a known risk factor for leukemia, excluding chronic lymphocytic leukemia, the study primarily focused on measuring incidence of leukemia and other cancer subtypes such as myelodysplastic syndromes, Hodgkin and non-Hodgkin lymphomas, and multiple myeloma.
Researchers said the study revealed a positive association between prolonged low-dose exposure to ionizing radiation and mortality from these hematological cancers.
"Health risk remains low at low-exposure levels. Nevertheless, the evidence of associations between total radiation exposure and multiple myeloma and myelodysplastic syndromes signals the necessity for future radiation studies to expand the discussion on radiation protection and occupational safety measures on a global scale," Richardson, et al. concluded.
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: dfornell@innovatehealthcare.com