Diabetes May Indicate Undiagnosed Pancreatic Cancer

A new study suggests that developing diabetes or rapid disease progression is an early warning sign of pancreatic cancer.

Researchers discovered that nearly 50% of all cases of pancreatic cancer in Lombardy and Belgium were developed within 1 year of patients being diagnosed with type 2 diabetes and initiating treatment, according to a study presented at the European Cancer Congress 2017.

"In Belgium 25% of cases were diagnosed within 90 days and in Lombardy it was 18%,” said researcher Alive Koechlin. “After the first year, the proportion of diagnosed pancreatic cancers dropped dramatically.”

Included in the study were prescription drug data for 368,377 patients with type 2 diabetes in Belgium between 2008 and 2013, and 465,311 patients in Lombardy. During this time, 855 and 1872 cases of pancreatic cancer were diagnosed in Belgium and Lombardy, respectively.

The investigators found that patients had a 3.5-fold greater risk of a pancreatic cancer diagnosis after the first 3 months of taking incretins, compared with those who took oral anti-diabetic treatments, according to the study. Incretins are hormones that cause the pancreas to create more insulin to lower blood sugar levels.

The researchers found that this risk of diagnosis dropped to 2.3-fold after 3 to 6 months of treatments, and to 2-fold after 6 months to 1 year. After the first year, the risk of developing pancreatic cancer for patients administered incretins plummeted to 1.7-fold.

For patients who were managing diabetes with oral drugs, switching to incretins or insulin was expedited among individuals who were diagnosed with pancreatic cancer, according to the study. Additionally, disease progression that resulted in switching to a more aggressive diabetes drug plus insulin was linked to a 7-fold increased risk of pancreatic cancer.

Prior to this study, the link between type 2 diabetes and pancreatic cancer was understood, but largely unknown due to the complexities of the association. Since incretin treatments stimulate insulin release in the pancreas, these drugs have been thought to increase the risk of cancer.

However, it is also known that pancreatic cancer can lead to diabetes in some patients.

“Our study shows that incretin therapies are often prescribed to patients whose diabetes is caused by a still undiagnosed pancreatic cancer. Because the pancreatic cancer finally becomes symptomatic and is thus diagnosed, it looks like it is the intake of incretin drugs that could be the trigger of the pancreatic cancer, while in reality, it is the pancreatic cancer that causes a deterioration of diabetes, which is followed by the prescription of incretins,” Autier said. “This phenomenon is called 'reverse causation'. Our study also shows that the reverse causation observed for incretin drugs is also observed for other anti-diabetic therapies, in particular for insulin therapy.”

Unfortunately, determining if a patient has undiagnosed pancreatic cancer has proven difficult. The investigators said that using prescription databases in similar ways to those used in their study could help create new methods to identify patients with early pancreatic cancer.

"There is currently no good, non-invasive method for detecting pancreatic cancer that is not yet showing any visible signs or symptoms,” Autier said. “We hope that our results will encourage the search for blood markers indicating the presence of pancreatic cancer, which could guide decisions to perform a confirmation examination like endoscopy.”

Until these optimal diagnostic tools are created, physicians should be educated about the risks and signs of pancreatic cancer in relation to diabetes, according to the study.

"Doctors and their diabetic patients should be aware that the onset of diabetes or rapidly deteriorating diabetes could be the first sign of hidden pancreatic cancer, and steps should be taken to investigate it,” Autier concluded.