TUESDAY, Jan. 31 (HealthDay News) -- A new Swiss-American study indicates that long-term use of the popular diabetes medication metformin may lower the risk of developing pancreatic cancer, at least among women.
The researchers also found that the long-term use of another class of diabetes medications known as sulfonylureas was associated with a "substantial" bump in pancreatic risk and long-term insulin use was linked to a bump in pancreatic cancer risk in men.
"This result is somewhat unexpected," the team wrote in its paper, which is published in the Jan. 31 online issue of The American Journal of Gastroenterology.
Pancreatic cancer is the fourth most deadly cancer in the United States, with an overall survival rate of less than 5 percent, even though it is fairly rare, according to the U.S. National Institutes of Health.
The researchers noted that previous research has suggested that metformin may lower the risk for other cancers, breast and ovarian cancer in particular.
To explore metformin's protective potential against pancreatic cancer, the team sifted through drug prescription, diagnostic, hospitalization and fatality information that had been collected by the British "General Practice Research Database." The data also included significant demographic information, such as smoking, alcohol use and body mass index.
The team honed in on statistics regarding nearly 2,800 patients (all under the age of 90) who had been diagnosed with pancreatic cancer for the first time between 1995 and 2009. Data concerning almost 16,600 patients who did not have pancreatic cancer was used as a comparison.
The result: Short-term use of metformin or sulfonylureas and/or insulin had no appreciable impact on pancreatic cancer risk.
However, long-term use of each of these medications did appear to have a sizeable impact on pancreatic cancer risk among diabetics. While female patients saw their risk go down with metformin treatment and up with sulfonylureas, male patients saw their risk go up with insulin.
Dr. Michael Choti, a professor of surgery and oncology at the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University in Baltimore, stressed the "importance of trying to identify causes for a devastating disease that is often diagnosed late."
"Over the years, many groups have tried to look at a variety of risk factors, dietary and other things, and there have been some reports over the years," he noted. "But nothing has really panned out well. So this is indeed an interesting study."
"But it's also important to say," Choti added, "that while these could be associations, we cannot really say that what we have here is a cause-and-effect. Pancreatic cancer is a multi-factorial disease. So, while it makes sense conceptually that these drugs could have an impact on the pancreas, which is a metabolic organ, it's still too early to be sure what's happening. And it's too early to recommend metformin as a preventive therapy for pancreatic cancer."
"So this is interesting and important," he said. "But it's not definitive."
For more on pancreatic cancer, visit the U.S. National Library of Medicine.