In a new study from UC Berkeley and the Pontifical Catholic University of Chile researchers have found that drinking water containing high levels of arsenic is associated with a 50% drop in breast cancer deaths.
The study was published in this month’s EBioMedicine journal and presented results from an analysis preformed in a region of Chile where the team looked at breast cancer mortality in a population that had been inadvertently exposed to high levels of arsenic.
The results demonstrated that instead of an increased rate of mortality, as has been observed in other cancer sites, breast cancer deaths were reduced to half, especially in women younger than 60 years of age, who saw a 70% reduction in breast cancer death rates.
“What we found was astonishing. We’ve been studying the long-term effects of arsenic in this population for many years, focusing on increased disease and mortality attributed to the historical exposure to arsenic in this population,” study lead author Dr. Allan Smith, UC Berkeley professor of epidemiology and director of the Arsenic Health Effects Research Program said in a Berkeley press release.
The Chilean city under analysis, Antofagasta, had switched to a source of water that originated from the Andes Mountains, which was later revealed to contain more than 800 micrograms per liter of arsenic, 80 times higher than the levels recommended by the World Health Organization
In their analysis, researchers tested human cells lines in vitro, and saw that normal breast cells were more resistant to arsenic, whereas breast cancer cells seemed to be more susceptible and die when exposed to this element.
Arsenic has been used for medicinal purposes before. In 2000 arsenic trioxide was approved by the Food and Drug Administration (FDA) as a treatment for a rare type of leukemia.
When asked if arsenic should be considered for the treatment of breast cancer, Dr. Smith replied “Not yet. We do not know if the treatment will work, but carefully designed clinical trials should take place as soon as possible based on this new evidence.”
As such, Dr. Smith and his collaborators in Chile are beginning to design clinical studies to evaluate arsenic treatment in advanced breast cancer patients.