diabetes and pancreatic cancer

Last edited 11/2022 and last reviewed 11/2022

Type 2 diabetes mellitus is likely the third modifiable risk factor for pancreatic cancer after cigarette smoking and obesity

  • epidemiological investigations have found that long-term type 2 diabetes mellitus is associated with a 1.5- to 2.0-fold increase in the risk of pancreatic cancer
    • a causal relationship between diabetes and pancreatic cancer is also supported by findings from prediagnostic evaluations of glucose and insulin levels in prospective studies (1)
    • insulin resistance and associated hyperglycemia, hyperinsulinemia, and inflammation have been suggested to be the underlying mechanisms contributing to development of diabetes-associated pancreatic cancer

New-onset diabetes may indicate subclinical pancreatic cancer, and patients with new-onset diabetes may constitute a population in whom pancreatic cancer can be detected early (1)

  • been reported that the prevalence of diabetes and impaired glucose tolerance in pancreatic cancer cases is as high as 80% (1,2)
    • in the majority of cases, diabetes associated with pancreatic cancer is diagnosed fewer than 2 years prior to the cancer diagnosis or during the cancer course
    • among patients with early-stage pancreatic cancer, diabetes has developed more often in patients with carcinoma of the head of the pancreas than in those with carcinoma of the body and/or tail of the organ
      • the reasons why diabetes develops in patients with pancreatic cancer remains unclear
  • older subjects with new-onset diabetes have an approximately 8 fold higher risk of having pancreatic cancer compared to the general population (2)

  • studies examining the association between diabetes and pancreatic cancer suggests that while long-standing diabetes is an etiologic factor for pancreatic cancer, new-onset diabetes is its manifestation (2)

  • majority of pancreatic cancer-associated diabetes is of recent onset, beginning up to two years preceding the diagnosis of cancer (2)

  • new-onset diabetes have a higher probability of subsequently being diagnosed with pancreatic cancer (3)
    • in a population based cohort of 2,122 diabetic individuals in Olmsted County, MN, we determined that 18 (0.8%) new-onset diabetic individuals aged 50 or older were diagnosed with pancreatic cancer within 3 years of meeting criteria for diabetes and the observed-to-expected ratio of pancreatic cancer in this cohort of newly diagnosed diabetes subjects was 7.9 (95% confidence interval [CI] 4.7-12.5)

  • there is a marked and continuous increase in prevalence of diabetes from 24 to 36 months preceding the diagnosis of pancreatic cancer and leading up to the time of diagnosis (2)

  • nearly half the patients with early stage, resectable tumors have diabetes (2)

Pancreatic ductal adenocarcinoma is most frequently detected at an advanced stage (4)

  • 5-year survival rate of 3-15%
  • people with long-standing type 2 diabetes (more than 5 years) have a 1-1.5-fold increased risk of pancreatic ductal adenocarcinoma compared with the general population
  • in individuals who have had type 2 diabetes for less than 1 year, the relative risk of pancreatic ductal adenocarcinoma increases to 5.4-fold
  • when diagnosed with pancreatic ductal adenocarcinoma, around 80% of patients have abnormal fasting glucose or glucose intolerance
  • diabetes experienced by most patients with pancreatic ductal adenocarcinoma is of recent onset (diagnosed less than 24-36 months before diagnosis of pancreatic ductal adenocarcinoma)
  • approximately 0·8-1% of individuals aged over 50 years with new-onset diabetes have diabetes secondary to pancreatic ductal adenocarcinoma