Older newly diagnosed diabetics have elevated pancreatic cancer risk

Patients 50 years of age or older who have recently been diagnosed with type 2 diabetes have an increased risk of being diagnosed with pancreatic cancer, study results show. But because the cancer is usually advanced to the stage of being unresectable by the time hyperglycemia is noted, it is unlikely that newly diagnosed diabetes will be a useful tool for screening asymptomatic individuals.

Disease-specific symptoms of pancreatic cancer generally don’t appear until the cancer has reached an advanced stage. Because of the recognized association between diabetes and pancreatic cancer, Dr. Dr. Suresh T. Chari and his colleagues at the Mayo Clinic College of Medicine in Rochester, Minnesota, investigated the potential value of new-onset diabetes as a marker of underlying pancreatic cancer. They used data from the Rochester Epidemiology Project to identify Minnesota residents first diagnosed with diabetes at age 50 or older between 1950 and 1994. To estimate the incidence of pancreatic cancer in the general population, the researchers analyzed data from the Iowa Surveillance, Epidemiology, and End Results (SEER) program. According to their report in the August issue of Gastroenterology, 2127 Rochester residents were diagnosed with diabetes, 18 of whom met criteria for pancreatic ductal carcinoma within 3 years of diagnosis. By the time diabetes was diagnosed, nine had cancer-related symptoms, such as abdominal pain, weight loss, and jaundice. The cancer could be resected in three patients.The observed-to-expected ratio of pancreatic cancer within the first 3 years of a diabetes diagnosis was 7.94. The observed/expected ratio was more pronounced in men (9.69) and in subjects aged 70 or older (9.91).Dr. Chari’s group writes, “The success of the strategy to use hyperglycemia as a screening tool to identify subjects with a high likelihood of having underlying undiagnosed pancreatic cancer will depend largely on our ability to differentiate pancreatic cancer-induced diabetes from type 2 diabetes using a serologic marker,” which has yet to be identified.(Source: Gastroenterology 2005;129:504-511: Reuters Health: Oncolink: August 2005.)