The findings may help doctors identify more people at risk for the potentially deadly cancer.
By Sheryl Huggins Salomon. Medically Reviewed by Kacy Church, MD
A type 2 diabetes diagnosis after age 50, called late-onset diabetes, is a known risk factor for pancreatic cancer, and in Latino and African-American people with diabetes who are diagnosed with pancreatic cancer within three years, pancreatic cancer itself may manifest as diabetes.
That’s what a study published June 18 in the Journal of the National Cancer Institute suggests, and the findings may help doctors identify more individuals at risk for pancreatic cancer, which has poor survival rates because doctors often don’t catch the disease early enough for treatment to be effective. Pancreatic cancer has a five-year survival rate of only 8.5 percent, according to the National Cancer Institute (NCI).
For the current study, authors studied the incidence of type 2 diabetes and pancreatic cancer in nearly 49,000 African-American and Latino people older than 50. From 1993 to 2013, about 32 percent, or about 15,800, of the study participants developed diabetes. During follow-up, researchers identified an additional 408 pancreatic cancer cases.
Over the study period, about 20 years, they found that diabetes was associated with a twofold risk of pancreatic cancer. But when researchers stratified the data, they observed the risk for pancreatic cancer was even higher among participants diagnosed with diabetes in the previous three years (called recent-onset diabetes). Within that time period, Latinos were four times more likely to develop pancreatic cancer, and African-Americans were three times more likely.
“Our results suggest that late-onset diabetes can be used as a marker to narrow down who is in a high-risk group for pancreatic cancer,” says the lead study author, V. Wendy Setiawan, PhD, an associate professor of preventive medicine at the Keck School of Medicine of the University of Southern California in Los Angeles. “Physicians should be aware that while the chance [of developing pancreatic cancer] is low, recent-onset diabetes could be an early sign of pancreatic cancer,” she adds.
The Association Between Pancreatic Cancer and Type 2 Diabetes in Minorities
The pancreas is a gland behind the stomach that secretes digestive enzymes and releases hormones, such as insulin and glucagon, that help to control blood glucose (sugar), according to Johns Hopkins University. According to the NCI, about 1.6 percent of people in the United States will be diagnosed with pancreatic cancer at some point in their lifetime.
The incidence of pancreatic cancer among black people specifically is about 25 percent higher than it is in white people, according to the American Cancer Society. Yet, says Setiawan, “Blacks and Latinos are understudied, and thus very little is known about the relationship between diabetes and pancreatic cancer in these two populations.”
Additionally, both black and Latino people have higher rates of type 2 diabetes than the general population, according to the American Diabetes Association. That’s why her team focused on those groups.
Rahil Bandukwala, DO, an endocrinologist at MemorialCare Saddleback Medical Center in Laguna Hills, California, who wasn’t involved in the research, says the results seem to align with what he’s seen in his nearly 20 years of practicing medicine, but he would be interested in seeing more long-term data. He notes a limitation of the study that the authors acknowledge in their paper: The research relied on self-reporting when determining the diabetes diagnoses, Medicare claims, and hospital discharge records. And so the recorded onset dates may have been imprecise. “It would be good to better understand when the diabetes truly came about and follow the participants out from there — to see who gets pancreatic cancer and who doesn’t.”
But previous research seems to support the current study’s findings. For example, nearly 40 percent of people with pancreatic cancer had also developed diabetes within the three years prior to their cancer diagnosis, according to the findings of a review of 500 medical records that was published in the March 2013 issue of Pancreas.
A Need for Better Pancreatic Cancer Screening Tools
Michael Choti, MD, a surgical oncologist at Banner MD Anderson Cancer Center in Gilbert, Arizona, who specializes in pancreatic cancer, says that study results so far, while interesting, aren’t cause for alarm. “Patients who develop late-onset diabetes shouldn’t panic and think Oh my God, that means I’m going to develop pancreatic cancer,” says Choti, who wasn’t involved in the current research.
But he notes that pancreatic cancer rates are on the rise, and current screenings for the disease fall short. Given that pancreatic cancer can be aggressive and survival rates so poor, he argues that better tools are needed to screen for early signs. “We don’t really have any screening tools, and even imaging [methods] of the pancreas, such as a CAT scan or MRI of the pancreas, are not perfect,” Choti explains. According to the U.S. Preventive Services Task Force, there are no official guidelines for pancreatic cancer screening.
Setiawan agrees with Choti. “There is an urgent need to find better ways to identify patients with early cancer in the group of patients who develop diabetes after age 50,” she says, adding that her team at the Consortium for the Study of Chronic Pancreatitis, Diabetes, and Pancreatic Cancer are “working diligently to develop tests that can better identify patients with recent onset diabetes who actually have pancreatic cancer at its earliest stage.”
“Finding the cancer at an early stage and treating it with surgical removal provides the best chance for a cure of the disease,” she adds.