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Texas will see the nation's second-highest number of new cases and deaths caused by liver cancer in 2018. The demographic most affected are Latinos, whose incidence rates are three to four times higher than that of their non-Hispanic white counterparts, according to research from UT Health San Antonio.
“Liver cancer rates are rising nationally, but are higher in our Latino population and we don’t know why,” said Amelie Ramirez, director of Salud America, a Latino-focused organization aimed at improving health through research and community initiatives.
A 2014 study in which Ramirez was a principle researcher found that the incidence of liver cancer rates among Latinos in South Texas “remains higher than elsewhere in the U.S. and warrants closer investigation” into risk factors unique to the population.
After completing followup studies, UT Health found that Latinos with liver cancer had much higher levels of aflatoxins than those without liver cancer. Aflatoxins are naturally occurring, cancer-causing chemicals produced by mold that can contaminate improperly stored foods. They are regularly found in staple commodities such as peanuts, pistachios, rice, sesame seeds, corn, and chili peppers, and in meats from animals who ingested contaminated food.
“We tried to dig down a little further,” Ramirez said. “What we are seeing in South Texas [liver cancer rates] doesn’t appear to point to [one reason] alone. There is something else going on, and it could be these aflatoxins."
Dr. Ahmed Kasseb, associate professor of gastrointestinal medical oncology at the MD Anderson Cancer Center in Houston, said that by the end of the year research by MD Anderson and UT Health San Antonio could yield more concrete information about whether Latinos have a genetic predisposition to liver cancer.
Environmental, cultural, and socioeconomic factors, higher diabetes and obesity rates, and genetic predisposition are all being considered as potential reasons for the uptick in liver cancer incidence in the Hispanic population.
Cancer rates have been declining consistently thanks to advances in technology and medicine, but liver cancer rates remain on the rise, having tripled in the United States since 1980.
In Texas in 2018, an estimated 4,420 new cases of liver cancer will be diagnosed, and 2,700 people will die from the disease, according to the American Cancer Society.
Kasseb told the Rivard Report that even healthy people are at risk for complications when aflatoxins are ingested.
He explained that research linking liver cancer with the ingestion of aflatoxins is decades old. More recently, a 2006 outbreak in Kenya led to 125 deaths in a region where aflatoxin contamination of maize had been a recurring problem.
"This has affected a lot of areas around the world, and there have been regulations to work on that and raise awareness," Kasseb said.
Both the U.S. Department of Agriculture and the Food and Drug Administration recognize aflatoxins as a serious health risk. Concentrations in the U.S. are limited to 20 parts per billion; commercial crops are routinely screened, and food supplies that test over the regulatory limit are considered unsafe for human consumption and destroyed.
However, these standards only apply to foods that cross state lines; they do not apply to foods produced and sold within the same state. Additionally, the FDA does allow corn, peanut, and cottonseed meal products contaminated with aflatoxins exceeding 20 parts per billion to be fed to livestock, which may impart small amounts of toxins in meat products.
According to the International Food Policy Research Institute, consumption of even tiny amounts of aflatoxin can have a cumulative effect, and can lead to liver damage, gastrointestinal dysfunction, decreased reproductive function, loss of appetite, and decreased growth.
Ramirez said the UT Health San Antonio study gauged aflatoxin exposure in 42 liver cancer cases and 42 non-cases, with Latinos comprising two-thirds of the population studied. For those with liver cancer, the odds of having detectable amounts of aflatoxin in their blood were six times higher compared to non-cases. Researchers have requested additional funding from the National Institutes of Health to complete a larger study that would include a deeper dietary assessment to explore possible aflatoxin links.
To reduce the rates of liver cancer, Kasseb said, patients and physicians need to pay special attention to "metabolic syndrome," a cluster of conditions such as hypertension, diabetes, obesity, and high triglycerides that occur together and increase the risk for health complications. Metabolic syndrome disproportionately affects the Hispanic population.
He said that metabolic syndrome is "like an epidemic in the U.S." and that patients and physicians need to learn how the condition may lead to more fatal outcomes if symptoms are not controlled.
"Anyone who fits the description of having metabolic syndrome should get an ultrasound of the liver to make sure they don't have fatty liver or liver cirrhosis," Kasseb said. "Metabolic syndrome is not very well recognized as a risk factor, and we want to raise awareness."
Liver cancer is the fifth leading cause of death for men and eighth leading cause of death for women, accounting for approximately 41,000 cancer cases and 29,000 deaths in the United States in 2017.
Of cancer diagnoses in Texas, liver cancer is the fifth most common cancer diagnosis in Latino men, and the 10th for Latino women, according to the Texas Cancer Registry. The 2016 census shows that nearly 60 percent of the total population in Bexar County is Hispanic.
While there is no way to completely prevent cancer, many liver cancers could be prevented by reducing exposure to known risk factors, such as limiting alcohol and tobacco use, limiting exposure to cancer-causing chemicals (such as aflatoxins, asbestos, and arsenic), and maintaining a healthy weight.
"Wellness always revolves around the same things: Controlling risk factors, diet, and exercise," Kasseb said. "Lifestyle modifications such as diet and exercise will help relieve fat from around the liver and diminish the risk factor."