A multi-center team led by researchers from the University of Washington School of Medicine in St. Louis have found a biomarker that predicts which pancreatic cysts can become cancerous with 95 percent accuracy compared to 74 percent of current clinical guidelines.
Pancreatic cancer kills more than 45,000 people in the United States mainly due to the fact that it is detected too late for surgery to eliminate and stop the spread of cancer. Cysts in the pancreas sometimes develop into invasive cancer, depending on the type of cyst, but these growths are often not cancerous, creating a dilemma for doctors who detect them by CT scans and MRIs.
Surgery to remove pancreatic cysts is often complex, so new tools are needed to identify which cysts are more likely to become cancer and which are not. Now researchers have taken a big step toward identifying the cysts that are likely to become cancerous, according to the magazine. 'Gastroenterology'.
By analyzing the fluid from the cysts in search of a biomarker, an antibody called mAb Das-1, the researchers were able to identify pancreatic cysts that are likely to become cancerous with an accuracy of 95 percent. Current clinical guidelines are only accurate at 74 percent.
"Some cysts have the potential to become pancreatic cancer, so there is the idea that we should err on the side of caution and eliminate cysts," explains first author Koushik K. Das, assistant professor of medicine in the Division of Gastroenterology at the University of Washington-. But pancreas surgery is complicated. It often requires the removal of the spleen, parts of the stomach, small intestine and bile duct. In an ideal world, we would only perform surgery on people whose pancreatic cysts will likely become cancer. That is, we probably do not operate on some people who need surgery and, sometimes, we operate when the cancer is not present because we are working with inaccurate information. "
According to Das, about 2 percent to 4 percent of patients aged 50 to 70 have pancreatic cysts, and that percentage increases to 8 percent or 9 percent in people over 80. The vast majority of patients have no symptoms, so when cysts are detected, doctors must decide whether to perform surgery, knowing that a typical patient 70 years of age or older may have other serious unrelated medical problems, such as heart, lung or kidney disease, which makes them less than ideal candidates for major abdominal surgery.
Although surgery is effective in eliminating precancerous cysts, between 1 percent and 2 percent of patients who undergo surgery do not survive. The complication rate of surgery can range between 30 percent and 60 percent. Das points out that these are high risks for removing cysts that could be harmless.
In the new study, Das worked with collaborators at the Massachusetts General Hospital in Boston, the Johns Hopkins School of Medicine in Baltimore, the Memorial Sloan Kettering Cancer Center in New York and the Rutgers-Robert Wood Johnson School of Medicine in New Jersey.
The research team collected fluid from the cysts of 169 patients who underwent surgery to remove pancreatic cysts. The researchers analyzed the fluid, using a test to detect the biomarker of the Das-1 antibody.
In previous research, the biomarker had been linked to pancreatic cysts at high risk of becoming cancerous. In the new study, the researchers found that the biomarker was more accurate than any current method for predicting cancer risk in these patients with pancreatic cysts.
The next step, says Das, is to see if the biomarker can identify pancreatic cysts that are likely to become cancerous before a patient undergoes surgery. As a gastroenterologist, Das is using endoscopic ultrasound to distinguish patients at risk for pancreatic cancer from those whose cysts often pose no threat. While patients are under anesthesia, insert a flexible tube with a camera through the mouth into the abdomen.
"At the end there is an ultrasound probe that allows us to examine the pancreas," he says. Then, under ultrasound guidance, we can collect fluid from the cyst with a needle so that it can be analyzed for Das-1 and assess the risk of cancer. "
Das has been collecting fluid samples for more than two years to begin accumulating a large enough number to validate the test. "Many cysts, if not most, should probably stay where they are, but assuming a risk because it is possible that it may be carcinogenic. If we had a better biomarker, we would not have to rely on imperfect clinical and radiographic information, "he says.