CA 19-9 tumor marker test especially important for early-stage patients, Mayo finds
Only 1 in 5 U.S. pancreatic cancer patients receive a widely available, inexpensive blood test at diagnosis that can help predict whether they are likely to have a better or worse outcome than average and guide treatment accordingly, a Mayo Clinic study shows. People who test positive for elevated levels of a particular tumor marker tend to do worse than others, but if they are candidates for surgery and have chemotherapy before their operations, this personalized treatment sequence eliminates the elevated biomarker's negative effect, researchers found.
The findings will be presented at the Western Surgical Association annual meeting Nov. 7-10 in Napa.
"This is another argument for giving chemotherapy before surgery in all pancreatic cancer patients and ending the old practice of surgery followed by chemo," says senior author Mark Truty, M.D., a gastrointestinal surgical oncologist at Mayo Clinic in Rochester, Minn. "The study answers an important clinical question and applies to every pancreatic cancer patient being considered for surgery."
The Mayo study, which used the National Cancer Data Base, is the first on the subject based on national data and is the largest of its kind, Dr. Truty says.
Researchers analyzed outcomes for 97,000 patients. The tumor marker whose impact they studied is known as CA 19-9. It is associated with several cancers, including pancreatic cancer, and can be measured in the blood of most people: 10 percent do not produce it. Pancreatic cancer patients who didn't secrete CA 19-9 were also studied.
Pancreatic cancer patients whose blood showed higher-than-normal CA 19-9 levels tended to have worse outcomes than others at the same stage of cancer, the study found. Surprisingly, the elevated tumor marker's negative effect on survival was most pronounced in patients diagnosed at an early stage, the researchers wrote.
"When we looked at how these patients did after surgical removal of their cancers, the only treatment sequence that completely eliminated the increased risk posed by CA 19-9 elevation was chemotherapy followed by surgical removal of the tumor," Dr. Truty says.
Another key finding was that only 19 percent of pancreatic cancer patients nationally have their CA 19-9 checked at diagnosis, far fewer than anticipated, he says. The CA 19-9 blood test has been standard for pancreatic cancer patients at Mayo Clinic for years.
Failing to test for and address elevated CA 19-9 means that many patients with above-normal levels may undergo significant surgeries that may not be as beneficial long term as anticipated, Dr. Truty says.
About 50,000 people are diagnosed with pancreatic cancer each year in the U.S. Historically, only about 7 percent of pancreatic cancer patients have lived at least five years after diagnosis. But advances such as the CA 19-9 test and improved chemotherapy, radiation and surgical techniques are improving survival odds for many patients, Dr. Truty says.
"Our conclusion is that every patient should have a CA 19-9 test at diagnosis. This is a simple, cheap and widely available test that allows personalization of pancreatic cancer treatment," Dr. Truty says, noting that the test costs about $170 — pennies on the dollar relative to the overall cost of a patient's cancer care. "Further, patients with any elevation of CA 19-9 should be considered for preoperative chemotherapy to eliminate this risk."