New-onset diabetes: a potential clue to the early diagnosis of pancreatic cancer.

Pancreatic cancer has a dismal prognosis because cancer-specific symptoms occur only at an advanced stage. If the cancer is to be discovered early, screening will need to be done in asymptomatic individuals. Because the incidence of pancreatic cancer is low, screening for asymptomatic cancer in the general population is not feasible; therefore, screening will need to be restricted to people at high risk of this disease. The proportion of patients with pancreatic cancer who also have hyperglycaemia or diabetes has previously been under appreciated. New data show that up to 80% of patients are either hyperglycaemic or diabetic, both of which can be detected in the presymptomatic phase. Diabetes has been shown to improve after pancreatic-cancer resection, suggesting that diabetes is caused by the cancer. Conversely, older patients with new-onset diabetes have about an eight-times higher risk of having pancreatic cancer than the general population. Recognition of new-onset diabetes as an early manifestation of pancreatic cancer could lead to the diagnosis of asymptomatic, early-stage pancreatic cancer. However, primary type-2 diabetes is common in the general population and pancreatic cancer is relatively uncommon, and the two forms of diabetes are clinically indistinguishable. The success of a strategy using new-onset hyperglycaemia and diabetes as a screening tool to identify people with a high likelihood of having asymptomatic pancreatic cancer will depend largely on our ability to differentiate pancreatic-cancer-associated diabetes from the more common type-2 diabetes by use of a (serological) biomarker.