A Pancreatic Cancer Puzzle

Pancreatic cancer mortality rise and fall among races

(RxWiki News) Scientists have a mystery on their hands when it comes to pancreatic cancer trends. Trends are different among whites and blacks – but no one knows why.

Researchers have discovered in a recent study that death rates from pancreatic cancer among white and black people have risen and fallen in opposite directions over the past 30 years.

These trends have scientists puzzled because, for the most part, the patterns can’t be explained by known pancreatic cancer risk factors such as smoking and obesity.

The researchers called for “urgent action” to gain better understanding of the disease to control increasing death rates.

"If you have ongoing abdominal pain, see your doctor."

In an effort to better understand the risk factors for and causes of pancreatic cancer, researchers led by Jiemin Ma, PhD, now affiliated with Brigham and Women's Hospital in Boston, studied long-term disease mortality (death) rates in the US.

The team of researchers used the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) database to examine mortality data for pancreatic cancer between 1970 and 2009 .

The patterns show a rise and fall among both genders and both races.

Pancreatic cancer death rates in white men declined 0.7 percent per year between 1970 and 1995, going from 24.8 per 100,000 to 20.4 per 100,000 in 1995. The mortality rates then reversed among white men and increased 0.4 percent a year through 2009, moving up from 20.4 to 21.5 per 100,000.

For white women, the rates increased 0.4 percent annually from 1970 to 1984, going from 14.6 to 15.3 per 100,000 and then remaining stable until 1988. The rates started to climb again in 1989 by 0.5 percent per year through 2009, reaching 15.9 per 100,000.

In contrast, the number of black men dying from pancreatic cancer increased 0.5 percent per year from 1970 to 1989, rising from 29.0 to 31.3 per 100,000. This was followed by a 0.9 percent annual decline through 2009, when 27.5 black men per 100,000 died of pancreatic cancer.

Death rates among black women increased the most of all groups, climbing 1.3 percent annually between 1970 and 1989, from 18.3 to 23.1 per 100,000, then decreasing by 0.5 percent through 2009 to 20.9 per 100,000.

Throughout the 30-year period, death rates among blacks were higher than among whites.

When these trends were analyzed in terms of risk factors for pancreatic cancer, the researchers were stumped.

For example, smoking is a major risk factor for pancreatic cancer, but the prevalence of smoking has declined among both races since 1965.

Obesity is known to be associated with a 20 percent increased risk of dying from pancreatic cancer. But obesity is prevalent among black men, whose pancreatic cancer death rates slid between 1989 and 2009. 

Improved techniques for detecting pancreatic cancer may be part of the reason for the rising incidence and mortality rates among whites, the authors of this study suggested.

“The decreasing trend in blacks over the past 10 to 15 years is particularly interesting because the prevalence rates of factors (i.e., obesity, diabetes and improved diagnosis) that are likely contributing to the recent increases in pancreatic cancer death rates in whites have also increased in blacks,” the authors wrote.

According to the authors, “This study underscores the needs for urgent action to curb the increasing trends of pancreatic cancer in whites and for better understanding of the etiology of this disease."

This study was published November 13 in the Journal of the National Cancer Institute.

This work was supported by the intramural research department of the American Cancer Society.

No conflicts of interest were reported by any of the authors.

Review Date: 
November 14, 2013