The Link Between Pancreatic Cancer and Diabetes

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Jaundice, weight loss, diminished appetite, back pain. They’re vague symptoms that can point to many things, including advanced pancreatic cancer. And though it’s not as widely known, so, too, can a sudden diagnosis of diabetes—particularly for those over 50, who’ve never dealt with diabetes before.

For 150 years, doctors have known about the link between pancreatic cancer and diabetes, says Suresh Chari, M.D.,* head of the Pancreas Interest Group in the Division of Gastroenterology and Hepatology at the Mayo Clinic in Rochester, Minnesota. Only recently, however, has that link become better understood.

Pancreatic Cancer and Diabetes: Related?

In 1998, during a fellowship at the Mayo Clinic, Chari was introduced to a 1994 New England Journal of Medicine article suggesting that a hormone secreted by the pancreas caused diabetes in patients with pancreatic cancer. “The paper was intriguing,” he remembers.

Chari and colleagues tried to replicate the findings, without success. But what they witnessed during the course of their research startled him. Half of the pancreatic cancer patients he worked with were found to have diabetes. “It was a serendipitous discovery and it made me wonder if the diabetes was happening before the cancer, and if so, how long before,” Dr. Chari says.

For the next several years, the doctor set out to find out. His work and the studies of others confirmed that in pancreatic cancer patients with diabetes, changes in blood sugar tended to appear two to three years before the diagnosis of cancer.

The utility of that two-year window was immediately obvious. If diabetes came first, and the cancer followed two or so years later, the intervening time could be used to monitor patients – and to learn more about how cellular changes in the pancreas can lead to cancer.

A New Study

Chari and his colleagues helped to prove that those who develop diabetes after the age of 50 have a higher risk of developing pancreatic cancer than the general population. Now, he and fellow researchers are deepening their knowledge with the largest study of the pancreatic cancer-diabetes link to date.

“It’s taken a long time for the world to accept this body of work,” Chari says. “Two years ago, the NCI said it was making the connection a research priority. We are now doing a study of 10,000 new-onset diabetics at a consortium of 10 centers, including Stanford, Cedars Sinai, Mayo, and others.” In May, researchers met to finalize their recruitment strategy. The study will soon accept participants.

To get involved, patients must be over 50, with blood sugar over 126, and not have met criteria for diabetes in the past. “We want to capture patients who, ideally, have been recently diagnosed,” explains Chari. “For example, people who have gone to the doctor for routine checkups, gotten their blood sugar checked, and found that it is elevated.” A list of participating research centers can be found at the Consortium to Study Chronic Pancreatitis, Diabetes, and Pancreatic Cancer website.

Developing a stronger grasp of how diabetes affects the pancreas could provide a gateway to new early detection strategies, Chari says. In the fight against pancreatic cancer, nothing could be more impactful. “Unfortunately this disease sneaks up on you. By the time you know you have it, it’s too late,” he says. “We want to find some strategy for screening. For pancreatic cancer, it’s a must.”

*After this story was published, Chari moved to MD Anderson Cancer Center in Houston, Texas.

To find out more about the consortium study, visit cpdpc.mdanderson.org.