Rate of Rare Liver Cancer High Among Russian Nuclear Workers, Particularly Women, Study Finds

Posted in News Release  |  Tagged Mayak Nuclear Workers, occupational radiation exposure, radiation, radiation exposure

WASHINGTON (August 28, 2025) — Five decades of health and cancer outcomes research with Russian nuclear workers finds higher rates of bile duct cancer and hepatocellular carcinoma among the workers, as well as unusually high rates in women of angiosarcoma of the liver, a form of cancer that is extremely rare.

It’s one of very few studies to examine liver cancer in people exposed to radiation in a chronic, low-dose occupational setting. Previous research on radiation exposure has focused on survivors of disasters like the Chernobyl explosion or the Hiroshima bomb.

The new findings published August 1 in the journal Radiation Research could be used to guide safer and better tailored radiation exposure standards for people worldwide who work in nuclear facilities or those exposed to other forms of radiation, including space exploration (“Angiosarcoma of the Liver and Other Hepatic Malignancies in the Russian Cohort of Mayak Nuclear Workers”).

“The importance of this work has to do with worker safety,” said Christopher Loffredo, PhD, professor of oncology and biostatistics and director of the Office of Global Oncology at Georgetown University’s Lombardi Comprehensive Cancer Center. “There are many types of radioactive materials and chemicals used in laboratories and the nuclear power industry. There’s also cosmic radiation exposure in settings like space travel. So these continue to be very timely questions that still need more work to get answers.”

The study is a continuation of research on the Mayak Workers Cancer Biorepository, an ongoing project funded for the past 12 years by the U.S. Department of Energy, in collaboration with Russian researchers and conducted with workers at the Mayak Production Association, a nuclear facility established by the Soviet Union in the Southern Ural Mountains region in the late 1940s.

The researchers drew on a trove of detailed health and occupational records, as well as tumor and tissue samples maintained by the Russian government on workers who were chronically exposed to ionizing radiation from plutonium while employed at a nuclear weapons factory between 1948 and 1998. In addition to the large cohort and extraordinary detail of the records, the data set is unique because around 20% of the workers are women.

A key finding from the latest analysis is the unusually high rate of angiosarcoma, a liver cancer that normally occurs in only around one in 100 million people. Among the 25,000 nuclear workers studied, researchers identified 13 cases, with most cases occurring in women.

While researchers initially suspected a biological reason for this difference, further investigation with Russian colleagues revealed another explanation: Women were more likely to work in the factory in the late 1940s and early 1950s, due to the shortage of male workers after World War II, before effective safety gear and industrial hygiene protocols were in place.

“In some cases they were handling plutonium with their bare hands,” Loffredo said. “This doesn’t rule out a biological reason for the higher rates of angiosarcoma, but it strongly suggests it might be because of the incredibly high doses they were exposed to, compared to the men who started just a few years later.”

Those with angiosarcoma were also likely to be plutonium metallurgical plant workers, the job with the highest exposure to plutonium. Tissue analysis found that the angiosarcoma patients had the highest doses of plutonium absorbed in the liver compared to other workers at the plant.

Researchers also found higher-than-normal rates of bile duct cancer and hepatocellular carcinoma among the nuclear workers, primarily in men.

Plutonium is an especially dangerous material because particles can be inhaled. These particles can then be absorbed into the bloodstream and deposited in the lungs, liver, bone and brain, where they remain forever while continuing to emit radiation constantly for the rest of the person’s life.

Next, researchers are following up on previous research to conduct genetic analysis on tumors taken from the nuclear workers, with a goal of better understanding the genetic changes caused by plutonium exposure, and how this causes angiosarcoma, bile duct cancer and hepatocellular carcinoma.

In addition to Loffredo, study authors include Felicia D. Atkinson, Bhaskar Kallakury, Jan Blancato, Timothy J. Jorgensen and David S. Goerlitz of Georgetown Lombardi; Evgeniya S. Grigoryeva, Gleb V. Sychugov and Tamara V. Azizova of Southern Urals Biophysics Institute, Ozyorsk, Russian Federation; and Scott C. Miller of the University of Utah, Salt Lake City.

This work was conducted as part of the Joint Coordinating Committee for Radiation Effects Research Project jointly funded by the U.S. Department of Energy and the Federal Medical-Biological Agency.

The authors report having no personal financial interests related to the study.