By Dennis Thompson
TUESDAY, April 2, 2019 (HealthDay News) -- Advances in chemotherapy and cancer monitoring can dramatically extend the lives of almost one-third of pancreatic cancer patients with tumors previously considered inoperable, researchers report.
It's good news for patients with a particularly deadly form of cancer that's been highlighted by the recent diagnosis of "Jeopardy!" host Alex Trebek with stage 4 pancreatic cancer.
About 35% of pancreatic cancer patients are diagnosed with tumors that have started to grow outside the pancreas and involve many critical blood vessels surrounding the organ, explained lead researcher Dr. Mark Truty. He is a cancer surgeon at Mayo Clinic in Rochester, Minn.
Those patients have historically been told that their cancer is inoperable, and that they have only another 12 to 18 months left to live, the researchers said.
But new chemotherapy regimens have given these patients a fighting chance when delivered appropriately in conjunction with radiation therapy and surgery, Truty and his colleagues found.
Patients who had three specific chemo-related factors in their favor tended to live much longer, the results showed.
"Historically, the average survival is typically less than two years. These patients' average survival was about five years," Truty said.
The three factors were:
- The amount of chemotherapy each patient received. "The more chemo they got, the longer they lived," Truty said.
- Blood levels of a chemical called CA19-9, which is released by pancreatic cancer cells. Low levels indicated that the chemo had done its job well, rooting out hidden pockets of cancer cells.
- A tumor that, when surgically removed, was found to be all or mostly dead due to chemotherapy. Positron-emission tomography (PET) scans were best at detecting when chemo had worked.
The prognosis for pancreatic cancer tends to be dire because it spreads rapidly, most often to the liver, lungs or abdominal cavity, Truty explained. Only about 15% of patients are diagnosed with tumors that haven't spread beyond the pancreas.
However, there's another third of patients whose cancer has spread to blood vessels but no other major organs, and researchers suspected that improved combination chemotherapies could make a difference in their outcomes.
The new study followed 194 Mayo Clinic patients over seven years who received chemo followed by radiation and surgery. About half of those patients came to Truty after being told elsewhere their cancer was inoperable.
The research team found people were more likely to live longer if they received more cycles of chemotherapy, enough to successfully kill their tumors.
About 29% of patients had all three factors, and their average survival time has not yet been calculated because more than half are still alive, the study authors said.
Another 29% had two of the factors and their median survival was just under five years, the findings showed.
"The more of those factors you had, the better you did," Truty explained.
To tell whether the chemo was killing cancer cells, researchers turned to two tools -- the CA19-9 test and PET scans.
Doctors typically use CT scans to judge when to operate and remove a tumor, Truty said. If the tumor has shrunk to a particular size, it's time to remove it.
But in pancreatic cancer, "CT is not a very good imaging study to determine response," Truty said. "In this study, in only 28% of people did the tumor actually shrink to any particular benefit."
CT scans are advanced versions of traditional X-rays, but PET scans are different -- they track the movement of radioactive tracer materials in the body that are drawn to living cells.
"If the PET scan of the tumor turned cold following chemotherapy, even if the CT scan was the same, that highly predicted that when a pathologist looked at the tumor following surgery, that cancer would be completely or mostly dead," Truty said.
This strategy produced impressive results, said Dr. Igor Astsaturov, an associate professor at Fox Chase Cancer Center in Philadelphia.
Astsaturov said it was "remarkable" that 94% of the patients in the study had no living cancer cells in the tumors that were surgically removed.
However, this sort of treatment is not available at just any hospital, Astsaturov warned.
"This type of surgery requires virtuoso technical skills and a range of expert supportive service available in specialized academic and high-volume cancer centers," Astsaturov said.
Cancer doctors should consider using PET scans and the CA19-9 test to determine how well chemo has worked for a patient before proceeding to radiation therapy and surgery, Truty explained.
"Right now," he added, "no one uses PET scans in pancreas cancer surgery and insurance providers typically don't cover it, but we found it was the most predictive" of patient survival.
The new study was published online April 2 in the Annals of Surgery.