Cancer risk in astronauts requires careful monitoring, concludes a study in which astronauts’ blood was stored for 20 years.
All fourteen astronauts in NASA’s space shuttle program had DNA mutations in their hematopoietic stem cells, according to the Nature Communications Biology study. (will open in a new tab) Aug. 31 concluded. The mutations, while unusually high given the age of the astronauts, were nonetheless below a key threshold of concern.
While this study is unique in that the astronauts’ blood is stored for such a long time, the results are not overwhelming. Instead, the researchers suggest that astronauts should undergo periodic blood screening to watch for possible mutations. (And this should be seen in context; another 2019 study, for example, found that astronauts don’t die of cancer from ionizing cosmic radiation.)
Related: NASA Spacecraft’s Last Voyage: Looking Back at Atlantis’ Last Mission 10 Years Later
However, monitoring programs will be critical as NASA aims for long-duration deep space missions through its Artemis program on the Moon and later human missions to Mars, the new research team said in a statement. (will open in a new tab). (The new study and the 2019 cancer study mostly looked at astronauts on short-term missions.)
The team decided to proceed with the new study in light of “growing interest in both commercial spaceflight and deep space exploration, as well as the potential health risks from exposure to various hazards associated with repetitive or long-term exploratory space missions.” This is stated in a statement by lead author, Dr. David Ghukasian and Icahn Mount Sinai Professor of Cardiology.
NASA recently changed its radiation requirements for astronauts, which critics say discriminates against women, who have historically had lower limits than male astronauts. (To date, information about other genders among agency employees has not been disclosed.)
(Image credit: NASA) (will open in a new tab)
The researchers found a higher frequency of somatic mutations in the genes of the 14 astronauts considered in the study, compared to the statistics for the population that has been in space.
The space cohort flew between 1998 and 2001 for an average of 12 days. Approximately 85 percent of the group were men, and the six astronauts were on their first mission.
The researchers took whole blood samples from the astronauts twice, exactly 10 days before the flight and on the day of landing. Leukocytes were collected once, three days after planting. The blood samples were then left intact in a freezer for 20 years at minus 112 degrees Fahrenheit (minus 80 degrees Celsius).
However, the somatic mutations seen in the genes were less than two percent. Those who exceed this threshold are at greater risk of developing cardiovascular disease and some forms of cancer, the statement said.
“The presence of these mutations does not necessarily mean that astronauts will develop cardiovascular disease or cancer, but there is a risk that this could happen over time due to constant and prolonged exposure to extreme deep space conditions,” Ghukasyan added.
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