- Pancreatic cancer is often a fatal disease because it tends to be diagnosed in later stages.
- Researchers say people with the most common form of this disease are far more likely to have had gallstones the year prior to their diagnosis.
- Some experts say this potential link needs more study, but researchers say it’s important to use any tool available to diagnose pancreatic cancer earlier.
People with pancreatic ductal adenocarcinoma (PDAC) are six times more likely to have had gallstones the year before their diagnosis than people without this type of cancer
In a new study, researchers say their findings indicate that gallstones could be a warning sign for the aggressive and often deadly form of cancer.
The study will be presented this weekend at the Digestive Disease Week 2022 meeting in San Diego. The research hasn’t been peer-reviewed or published yet.
PDAC is the most common form of pancreatic cancer, accounting for more than 90 percent of cases. It often is fatal because it tends to be diagnosed in later stages.
“Pancreatic cancer can be difficult to diagnose and then chances of survival are slim,” said Dr. Marianna Papageorge, the study’s lead researcher and research fellow at Boston Medical Center, in a statement. “Our findings suggest that gallstone disease may be a way to better diagnose this type of cancer – meaning we could save more lives.”
Researchers used data from the SEER-Medicare database from 2008 to 2015.
They identified 18,700 people with PDAC, then compared them to an average of 99,287 people per year from the same database.
During the year before being diagnosed with PDAC, 4.7 percent of the people were also diagnosed with gallstone disease, with 1.6 percent having their gallbladders removed.
Among non-cancer patients, only 0.8 percent had gallstones, with 0.3 percent having their gallbladders removed.
“Gallstone disease does not cause pancreatic cancer but understanding its association with PDAC can help combat the high mortality rate with pancreatic cancer by providing the opportunity for earlier diagnosis and treatment,” Papageorge said.
Dr. Anton Bilchik, a surgical oncologist and chief of medicine at Saint John’s Cancer Institute at Providence Saint John’s Health Center in California, told Healthline no one knows the exact cause of pancreatic cancer.
There are, he noted, numerous signs.
“There is a higher incidence in patients with diabetes, morbid obesity, and those with a family history,” Bilchik said. “Gallstone disease is extremely common and this is one of the first studies to show a higher incidence of pancreatic cancer in patients with gallstone disease.
“The reason for this is unclear and it is important to note that obese patients, for example, have a higher incidence of gallstones (and) diabetes, as well as pancreatic cancer,” Bilchik said. “It is therefore important for the authors to evaluate whether other risk factors influence the findings of the study.
“The authors speculate that inflammation caused by gallstone disease may play a role in the development of pancreatic cancer. While this is interesting, it is pure speculation at this point,” he added.
Dr. David Beatty, a general practitioner in London, told Healthline gallstones do occasionally block the pancreatic duct leading to pancreatitis.
“Pancreatitis is one of the factors that increase the risk of pancreatic cancer,” Beatty said. “This is one possible mechanism whereby gallstones lead to pancreatic cancer.”
“The other question is whether there is some other disease, condition, or risk factor that is common to both diseases,” Beatty added. “I’ve looked at the various factors that increase the chance of getting these two conditions. Five factors appear on both lists: Age; both conditions are more common in older people; obesity; excess alcohol increases the risk of cirrhosis, which in turn increases the chance of gallstones; diabetics are more susceptible to both; (and) Crohn’s disease.”
“There are a lot of factors at play, and I feel the cause for the association is likely to be multifactorial,” Beatty noted.
One expert found the study problematic, saying it shouldn’t affect screening recommendations.
“The problem with a study like this is that it’s not looking at the presence of gallstones, but the diagnosis of gallstones,” Dr. Venu Pillarisetty, a surgical oncologist who specializes in pancreatic cancer at Fred Hutchinson Cancer Center in Seattle, told Healthline.
“Patients with pancreatic cancer are often initially misdiagnosed as having gallstone disease when they, in fact, are presenting with symptoms of pancreatic cancer,” Pillarisetty said. “Although they have gallstones, it may not be the actual cause of their symptoms. Since about 10 to 15 percent of the adult population has gallstones, you can see how it’s underestimated in both pancreatic cancer patients and their control group.”
“Patients with pancreatic cancer are more likely to have had a test that can diagnose gallstones (ultrasound) than most people, so it looks like more of them have gallstones,” Pillarisetty noted. “Gallstones are so common that it is not an indication for screening.”
The study’s authors said the frequency of people with gallstones who don’t get cancer could factor into future research by looking more closely at laboratory findings and imaging for specific factors related to gallbladder disease that could indicate which patients might have or develop pancreatic cancer.
“It is such a terrible disease, and survival is so low,” Papageorge said. “People present at such advanced stages, so anything we can do to try to diagnose people earlier and make sure that they’re getting curative treatment is crucial. This might be a key to better understanding next steps in screening, management, and earlier diagnosis.”