Pancreatic Cancer Risk Rises with High Lead, Arsenic and Cadmium

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Several elements commonly found in the environment, namely arsenic, cadmium, and lead, may increase the risk of developing pancreatic cancer, according to a new study published in Gut. On the positive side, the study also reported that high levels of nickel and selenium appear to reduce pancreatic cancer risk.

Toenail samples can accurately reveal heavy metal levels

Pancreatic cancer is a notoriously lethal form of cancer, even when it is diagnosed early, which does not occur often. One reason pancreatic cancer is not identified in its early stages is that the signs and symptoms (e.g., upper abdominal pain, jaundice, loss of appetite, weight loss, blood clots, depression) often don’t appear until the disease is advanced.

The most common type of pancreatic cancer starts in the ducts of the organ and is called exocrine pancreatic cancer. Endocrine pancreatic cancer, which begins in the cells that produce hormones, is diagnosed much less often.

The new study involved 118 patients who had exocrine pancreatic cancer and 399 controls from eastern Spain. Toenail samples were collected from all the participants and evaluated for the levels of 12 different trace elements. Nails are an excellent depository of metals in the human body.

Overall, the investigators found that levels of certain trace elements were either significantly lower or higher among the cancer patients when compared with the controls, and that the lower or higher the element levels, the lower or greater was the risk of pancreatic cancer.

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Specifically, compared with controls, the risk of pancreatic cancer was 2, 3.5, and more than 6 times greater among patients who had the highest levels of arsenic, cadmium, and lead, respectively.

On the positive side, however, patients who had the highest levels of nickel and selenium were between 33% and 95% less likely to have pancreatic cancer than individuals who had the lowest levels of these elements.

Although the causes of pancreatic cancer are not known, experts have identified some risk factors. They include smoking (tobacco contains cadmium and other trace metals), diabetes, overweight or obesity, increasing age, and chronic inflammation of the pancreas (pancreatitis). One-third of all pancreatic cancer cases are believed to be associated with smoking.

Lead can be found in some paints, emissions from burning of fossil fuels, and as a by-product of many manufacturing processes. Lead has been shown to cause abortion and to damage the male reproductive system, and the National Toxicology Program lists lead as “reasonably anticipated to be a carcinogen.”

Arsenic can be found in nature, but it is also used to make insecticides, fungicides, and weed killers, and to preserve wood. The Department of Health and Human Services has named arsenic as a known carcinogen, and studies show that ingesting inorganic arsenic increases the risk of skin cancer and tumors of the bladder, kidney, liver, and lung.

The authors of the latest study concluded that their results “support an increased risk of pancreatic cancer associated with higher levels of cadmium, arsenic, and lead, as well as an inverse association with higher levels of selenium and nickel.” If their findings can be replicated in further studies, the information would indicate an important role of these elements in pancreatic cancer.

SOURCES:
Amaral AFS et al. Gut 2011 Dec; DOI:10.1136/gutjnl-2022-301086
National Toxicology Program

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