Mission to Mars Would Double Astronauts' Cancer Risk

Deep space travel exposes cells to radiation and heavy ions, researchers say

By Mary Elizabeth Dallas

Thursday, June 15, 2017

THURSDAY, June 15, 2017 (HealthDay News) -- Once astronauts leave the Earth's protective magnetic field, their cancer risk would soar while traveling to Mars, new research indicates.

Scientists said radiation exposure during a long-term deep-space mission would not only affect already damaged cells but also healthy ones nearby, doubling cancer risk.

Cosmic rays cause significant cell damage due from exposure to radiation, protons and heavy ions, the authors explained. Previous research has shown the health risks of deep space travel include cancer, cataracts, acute radiation syndromes, and problems with circulation and the central nervous system.

Typical risk models, including those used by NASA, assume radiation cancers are caused by DNA damage and mutations. These models, however, are based on much shorter times than a Mars mission would require, researchers noted.

"Exploring Mars will require missions of 900 days or longer and includes more than one year in deep space where exposures to all energies of galactic cosmic ray heavy ions are unavoidable," said study author Francis Cucinotta. He's a space physicist at the University of Nevada, Las Vegas.

"Current levels of radiation shielding would, at best, modestly decrease the exposure risks," Cucinotta said in a university news release.

The new study, published online recently in Scientific Reports, said that on a longer mission into deep space, cancer risk would spread to otherwise healthy "bystander" cells that are near damaged ones.

"Galactic cosmic ray exposure can devastate a cell's nucleus and cause mutations that can result in cancers," Cucinotta said. "We learned the damaged cells send signals to the surrounding, unaffected cells and likely modify the tissues' microenvironments. Those signals seem to inspire the healthy cells to mutate, thereby causing additional tumors or cancers."

The authors said more study of long-term exposure to cosmic rays is needed before astronauts venture into deep space.

SOURCE: University of Nevada, Las Vegas, news release, June 5, 2017

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