Nuclear Workers Face Higher Mesothelioma Risk

Pleural mesothelioma is most often associated with asbestos exposure, but a new study suggests that nuclear workers may also be at higher risk for the cancer because of long-term, low-level radiation.

A new National Institute for Occupational Safety and Health (NIOSH) study pooled a group of 119,195 US nuclear workers. The workers were employed at one of four Department of Energy nuclear weapons facilities or at the Portsmouth Naval Shipyard. They were followed from the start of their radiation work, between 1944 and 1952, though 2005. Their risk of death from mesothelioma and other cancers was then compared to that of the general population.

“For most outcomes, mortality was below expectation compared to the general population, but mesothelioma and pleural cancers were highly elevated,” reports author Mary Schubauer-Berigan of NIOSH in the journal Radiation Research. Schubauer-Berigan notes that the mean dose of radiation among the studied workers was 20 mSv. The maximum allowable occupational exposure level for radiation is 50 mSv in a single year.

The mesothelioma risk from radiation was elevated among nuclear workers whether or not they had ever been smokers. Birth year and gender also appeared to have no impact on the risk for developing mesothelioma. Because it can take decades for mesothelioma to develop, the authors suggest that regular follow-up on the health of nuclear workers is critical. Many former asbestos workers have similar follow-up screenings.

The study reflects what previous research has found regarding the relationship between ionizing radiation and mesothelioma. A multi-center study released earlier this year found that patients who were treated with ionizing radiation for a blood cancer earlier in life had a significantly higher lifetime risk for malignant mesothelioma.

Pleural mesothelioma, the most common form of this rare cancer, starts on the pleural membrane that surrounds the lungs. Its irregular shape, fast growth, therapeutic resistance, and proximity to critical organs can make it extremely difficult to treat.

Sources:

Schubauer-Berigan, M et al, “Cancer Mortality through 2005 among a Pooled Cohort of U.S. Nuclear Workers Exposed to External Ionizing Radiation”, May 26, 2015, Radiation Research, Epub ahead of print.

Li, X, et al, “Malignant (Diffuse) Mesothelioma in Patients with Hematologic Malignancies: A Clinicopathologic Study of 45 Cases”, April 6, 2013, Archives of Pathology and Laboratory Medicine, Epub ahead of print.