Pancreatic cancer death rates for whites and blacks in the United States are going in two different directions. Rates among whites have been climbing since the late 1990s. The rates for blacks have been falling since peaking in 1989, according to an American Cancer Society analysis published November 7 in the Journal of the National Cancer Institute.

This is a shift from the past: From the 1970s to the early to mid-1990s, whites’ pancreatic cancer death rates declined dramatically, while blacks’ rose.

But even with the flip-flopping trends, blacks’ pancreatic cancer death rates are still substantially higher than whites’ – for both men and women.

 

“We conducted the analysis to assess the contribution of known risk factors, such as smoking and obesity, to these trends,” says Ahmedin Jemal, Ph.D., one of the study’s authors and vice president for surveillance and health services research at the American Cancer Society.

The researchers have a few theories as to what might be going on here. Obesity, they write, may be one of the factors contributing to the rise in death rates among whites. Obesity is linked to an increased risk of death in patients with pancreatic cancer, and obesity is increasing among whites. However, obesity also is up among all groups in the U.S. compared with the 1980s and 1990s, so that can’t be the whole explanation.

Another possibility is that the increase among whites could be due to modern diagnostic techniques, which help identify more cases of this type of cancer than doctors could previously detect. Pancreatic cancer is notoriously hard to find, especially in its early stages, so it is possible that many pancreatic cancer deaths went unrecognized in the past. But, again, this may be true for blacks as well – so still no clear explanation for why pancreatic cancer death rates are down among this group.

One other possibility the authors suggest has to do with smoking, which is linked to pancreatic cancer. Declining smoking rates in the U.S. have contributed to an overall decrease in pancreatic cancer death rates since the 1970s. It may be that the smoking-related decline in pancreatic cancer death rates was delayed for blacks – and is occurring now as opposed to during the 1970s and 1980s, when it happened for whites.

These theories are just a start, though; the authors conclude that the difference in pancreatic cancer death rates between whites and blacks is “largely unexplainable by known risk factors.” To get to a clearer answer, Jemal says, more research is needed. “In the meantime, clinicians should advise their patients to maintain a healthy body weight and to quit cigarette smoking in order to reduce the future burden of pancreatic cancer in the entire population.”

 

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