Predicting pancreatic cancer outcomes prior to surgery

Cancer

Predicting pancreatic cancer outcomes prior to surgery

By
Joel Streed

November 29, 2022

Dr. Truty, seated, holding a 3D model of a pancreas, talking to a patient. — Mark Truty, M.D., holding a 3D model of the pancreas and surrounding blood vessels.

By Chloe Corey

Pancreatic cancer is considered one of the least survivable forms of cancer. However, in new research published in Journal of the National Comprehensive Cancer Network, Mayo Clinic investigators demonstrated a way to predict long-term survival outcomes with high accuracy prior to surgery for patients diagnosed with borderline resectable or locally advanced pancreatic cancer.

Pancreatic cancer is categorized as borderline resectable or locally advanced when the tumor has not spread to other organs but has grown outside the pancreas to wrap around veins and arteries.

By using positron emission tomography (PET) scans with 18-fluorodeoxyglucose (FDG) tracer, the researchers were able to predict and assess a patient’s response to neoadjuvant chemotherapy prior to surgery in this subset of patients with more complex tumors involving blood vessels.

"The paper we just published is on our experience looking at how well a PET scan predicts final pathology," says Mark Truty, M.D., a hepatobiliary and pancreas surgeon at Mayo Clinic, a researcher with the Mayo Clinic Comprehensive Cancer Center’s Hepatobiliary SPORE, and senior researcher on the study. "We found that if the PET scan shows a significant improvement, then that highly correlates with what the pathologist finds in the tumor after surgery, and that it was superior to looking at tumor markers, like CA 19-9."

According to Dr. Truty, previously the surgeon wouldn’t know whether the chemotherapy was effective in killing cancer cells until after surgery.

"If we think the chemotherapy we are giving before surgery is going to change that patient’s outcome, we must prove that it’s effective. Otherwise, why bother taking the chemotherapy," says Dr. Truty. "So the question becomes, how do we know what we are giving patients is effective?"

In many cancers, the answer is to repeat computerized tomography (CT) or magnetic resonance imaging (MRI) to determine the treatment’s efficacy. However, these traditional imaging approaches have significant limitations, especially with borderline resectable or locally advanced pancreatic cancer, and typically do not change with treatment nor do they predict outcomes after surgery.

Another common way to measure efficacy is to monitor blood-based biomarkers, like CA 19-9.

Ajit Goenka, M.D.

"CA 19-9 is the only biomarker that is available for patients diagnosed with pancreatic cancer," says Ajit Goenka, M.D., a Mayo Clinic radiologist and co-lead author of the study. "It does have some utility, but it also has a lot of false positives and false negatives."

Additionally, Dr. Truty says measuring CA 19-9 levels is not possible in about 40% of patients because they either don’t produce the molecule or the biomarker levels are normal, even when the PET scan shows active cancer.

Dr. Goenka says this leaves Dr. Truty and his colleagues without any reliable options for assessing the likelihood of long-term outcomes before taking a patient to the operating room. It also leaves patients with more questions than answers heading into a highly complex surgery.

"By integrating metabolic imaging with radiotracers such as FDG into the care pathway, we can make those informed decisions and have the right conversations with our patients," says Dr. Goenka. "We are measuring those outcomes that really matter to our patients and are not just of academic interest."

Dr. Truty says if a patient is diagnosed with pancreatic cancer and will receive chemotherapy prior to surgery, a PET scan should be done before starting chemotherapy and then again afterwards to compare.

"If we see responses on the PET scan, we can be assured the chemotherapy is effective. If not, then we need to consider changing the regimen to maximize the benefit," he says. "These scans, in addition to the tumor markers, give physicians a more accurate prognosis of outcomes prior to surgery."

"The most important message for patients is that there is hope," says Dr. Goenka. "Pancreatic cancer is a highly morbid disease, but we have made inroads to being able to achieve much superior outcomes."

Other study authors included: Amro Abdelrahman, M.B.B.S.; Roberto Alva-Ruiz, M.D.; Jennifer Yonkus, M.D.; Jennifer Leiting, M.D.; Rondell Graham, M.B.B.S.; Kenneth Merrell, M.D.; Cornelius Thiels, D.O.; Christopher Hallemeier, M.D.; Susanne Warner M.D.; Michael Haddock, M.D.; Travis Grotz, M.D.; Nguyen Tran, M.D.; Rory Smoot, M.D.; Wen Wee Ma, M.B.B.S.; Sean Cleary, M.D.; Robert McWilliams, M.D.; David Nagorney, M.D.; Thorvardur Halfdanarson M.D.; and Michael Kendrick, M.D.