Pervasive ‘forever chemicals’ increase risk of liver cancer, researchers report

The ubiquity of the class of toxic substances commonly referred to as “eternal chemicals” is well established. Now, medical researchers have focused on their effects on a crucial component of the human body’s internal filtration system: the liver.

In a peer-reviewed study published this month in JHEP Reports, a sister publication to the Journal of Hepatology, researchers at the University of Southern California’s Keck School of Medicine found that those most exposed to the chemical perfluorooctane sulfonic acid were 4.5 times more likely to develop liver problems. cancer than those least exposed to it.

Scientists’ understanding of the effects of “eternal chemicals” has steadily evolved since 2015, when researchers observed that the chemicals – varieties of perfluoroalkyl and polyfluoroalkyl substances, known by the acronym PFAS (pronounced PEE-fahs”) – were present in more than 95% of blood serum samples collected from the general population of the United States. Last year, scientists noted the presence of PFAS for the first time in snow and slush on top of Mount Everest.

PFAS are known as forever chemicals because of how slowly they break down in the environment and how persistently they accumulate in the human body and other organisms. Commonly used in household items such as non-stick pans, cleaning products, and stain-resistant coatings on fabrics and carpets, have been shown to increase the risk of certain cancers, suppress immune system response, decrease fertility and lead to developmental delays in children.

Although previous research has linked occurrences of liver cancer in animals to PFAS, the study is one of the first to link the most common form of liver cancer in humans, hepatocellular carcinoma, to the products chemicals.

Jesse Goodrichan environmental epidemiologist who was one of the study’s lead authors, said he and his colleagues examined blood samples taken from participants in a large-scale research project conducted in 1999-2000 and then tracked the medical histories of those participants two decades later.

Goodrich and his fellow researchers identified 50 participants who over time were diagnosed with liver cancer and compared their blood samples from 20 years with those of 50 people in the project who did not develop cancer. The results showed that those whose blood samples placed them in the top 10% of participants with PFAS exposure in 2000 had a higher risk of developing liver cancer than those with the lowest exposure.

“A very important part of the studies is actually being able to say that before these people got cancer, they had higher levels” of chemicals, Goodrich said. “And that helps us determine that it’s more likely in this situation that it’s actually PFAS that are associated with cancer, as opposed to some sort of chance.”

Goodrich said one of the most critical implications of the findings was the high mortality rate associated with liver cancer, which in 2020 was the third deadliest form of cancer in the world. The five-year survival rate for those diagnosed with liver cancer is about 20%.

“Any increase in risk is unacceptable,” Goodrich said.

Researchers have also found that PFAS disrupts normal metabolic functions of the liver, which can lead to a condition known as non-alcoholic fatty liver disease. The study noted that cases of fatty liver disease have increased worldwide in recent years; by 2030, researchers say, nearly a third of all American adults could be diagnosed with the disease.

The results on PFAS and liver cancer were made public about a week after the publication of a report from the National Academies calling for increased testing of people with a history of high chemical exposure.

This includes people “exposed at work, those who have lived in communities where contamination has been documented and those who have lived where contamination may have occurred”, according to the academies study, such as people living in close proximity airports, military bases, sewage treatment plants, farms, landfills and incinerators.

For those with 2 nanograms per milliliter of PFAS in their blood, the academies recommend routine screening for high cholesterol and breast cancer. For those with higher levels, an annual thyroid test is recommended, as is regular screening for kidney and testicular cancer.

“What these recommendations do is help us start the conversation about the kinds of medical care that people who have been exposed to this exposure should start receiving,” said Jane Hoppin, a member of the academies committee that issued the recommendations. Hoppin, who is also an environmental epidemiologist at North Carolina State University, said the recommendations are meant to supplement advice from the Centers for Disease Control and Prevention.

Beyond the health risks of PFAS, the economic toll of regular chemical exposure can be high. Researchers at New York University’s Grossman School of Medicine have found that the combined cost of medical bills and lost worker productivity from PFAS-related illnesses is at least 5.5 billions of dollars nationwide.

Their peer-reviewed studypublished in the journal Exposure and Health, identified 13 conditions, including cancer, thyroid disease, infertility and diabetes, that will cost Americans up to $63 billion over the lifetime of the country’s current population .

Leonard Trasande, the report’s lead author, said his team’s research has underscored the need for policy and action to reduce the use of products containing PFAS. “There is a large and rapidly accumulating body of evidence supporting the effects of PFAS on the entire American population, from cradle to grave,” he said.

Trasande noted that some policymakers have questioned the expense of moving away from the use of products containing chemicals, which are commonly found in food packaging, furniture and oil-resistant clothing and at the water.

“A lot of people say it’s too expensive,” Trasande said. “But the reality is that we are currently paying in sickness and disability if we do nothing. And so this study really adds to the case for action.

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Trasande estimates that 100 million Americans have enough PFAS in their water to contribute to disease and disability and argues that exploring techniques to reduce this contamination is crucial, even though many consider it too costly.

Potential methods emerge. On August 18, researchers at Northwestern University announced that they had developed a new way to break down a group of PFAS compounds. In a study published in the journal Science, they detailed how they were able to destroy PFAS compounds by heating them in dimethyl sulfoxide with sodium hydroxide.

PFAS “are persistent and bioaccumulative pollutants present in water resources at concentrations harmful to human health,” the researchers noted. They called the combination “the Achilles’ heel of Forever Chemicals”.

Linda Birnbaumthe former director of the National Institute of Environmental Health Sciences, said thousands of new chemicals have been and are still being introduced into the environment, even though “we have so little information about their impacts at long term on our health”.

“Some of them that we know have led to climate change – we know that’s a problem,” said Birnbaum, a toxicologist and researcher in residence at Duke University’s Nicholas School of the Environment. “But many of these contaminants are ubiquitous.

“These chemicals are everywhere, and they are in all of us.”

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