5 things to know about pancreatic cancer
"It's not a particularly common cancer," says Mark Truty, M.D., a surgical oncologist at Mayo Clinic. "The lifetime risk of pancreatic cancer for any given patient without any predisposing risk is only 1 to 3%."
According to the National Cancer Institute, pancreatic cancer accounts for 3.2% of all new cancer cases, but it causes nearly 8% of all cancer deaths. And the five-year survival rate for pancreatic cancer is just 10.8%.
Here are five things everyone should know about this deadly cancer:
- Pancreatic cancer is aggressive and causes nonspecific symptoms.
"For 50% of patients at the time of their diagnosis, we find that the cancer has spread outside the pancreas to other organs, meaning stage four metastatic pancreas cancer," says Dr. Truty.
This happens for two reasons. First, pancreatic cancer cells are particularly aggressive. They accumulate and form tumors and spread to nearby organs at a rapid pace. Second, pancreatic cancer rarely causes symptoms before it has spread beyond the pancreas. And when it does cause symptoms, they are nonspecific, such as abdominal pain, back pain, or weight loss, all of which are more likely to be caused by something other than pancreatic cancer.
"It is not feasible to investigate every person with indigestion, gas, abdominal pain, or back pain, because a small proportion of them will have this cancer," says Santhi Swaroop Vege, M.D., a gastroenterologist at Mayo Clinic.
"It isn't until we see really specific things like jaundice, or skin turning yellow, or stools turning a lighter color, or urine getting darker, or new onset diabetes, that we associate symptoms with pancreatic cancer," says Dr. Truty.
Another specific symptom of pancreatic cancer is diabetes that suddenly becomes difficult to treat.
- Diagnosing pancreatic cancer is a multi-step process.
When a doctor suspects a patient might have pancreatic cancer, the first step is imaging tests to visualize the internal organs. Computerized tomography (CT) scans are often used.
"We conduct what we call a pancreas protocol CT scan," says Dr. Vege. "If the radiologist confirms a mass in the pancreas, then we are 90% certain it's pancreatic cancer." If a CT isn't possible for some reason, or if a CT is inconclusive, magnetic resonance imaging (MRI) might be used. If imaging confirms a strong likelihood of pancreatic cancer, the next step is a blood test.
"Once we have a CT scan suggesting pancreatic cancer, we do a blood test for a tumor marker called CA19-9, because 85 to 90% of people with pancreatic cancer have high values," says Dr. Vege. " If the blood test confirms high values for CA19-9, we use it as a baseline test to follow the disease after we begin treatment."
The blood test doesn't confirm pancreatic cancer, as some people with pancreatic cancer don't have elevated CA19-9 levels. A final diagnosis requires a biopsy (a tissue sample for testing). "No cancer is a cancer until you have a biopsy to prove it," says Dr. Vege.
At Mayo Ciinic, a tissue sample is commonly collected during an endoscopic ultrasound (EUS). During the procedure, the ultrasound device is passed through a thin, flexible tube (endoscope) down the esophagus and into the stomach, from which a needle can be inserted into the pancreas to collect tissue.
The tissue sample is then tested to confirm a diagnosis of pancreatic cancer. If the diagnosis is confirmed, the tissue is also analyzed for markers that might help determine the most effective treatment for that person's cancer.
- The cause of most pancreatic cancers is unclear.
Doctors have identified some factors that may increase the risk of pancreatic cancer, including smoking, diabetes, chronic inflammation of the pancreas (pancreatitis), obesity, and family history, but the cause is not clear.
"For the vast majority of patients, there's no associated predisposition other than maybe some behaviors such as smoking, or diabetes," says Dr. Truty.
"Approximately 10% of pancreatic cancers have a hereditary basis," says Dr. Vege. "And only about 8% of pancreatic cancers are familial pancreatic cancers, which means the patient has a first-degree relative or second-degree relative with pancreatic cancer."
Other pancreatic cancers are linked to a family history of genetic syndromes that can increase cancer risk, including a BRCA2 gene mutation, Lynch syndrome and familial atypical mole-malignant melanoma (FAMMM) syndrome. "Only about 2% of pancreatic cancers are considered syndromic hereditary pancreatic cancers, which are linked to inherited clinical syndromes," says Dr. Vege.
Research has shown the combination of smoking, long-standing diabetes and a poor diet increases the risk of pancreatic cancer beyond the risk of any one of these factors alone.
- There's no good way to screen for pancreatic cancer.
Doctors don't yet have a good way to screen large portions of the population for pancreatic cancer. "There is no good screening test that is cheap, effective, safe, and can be rolled out like a Pap smear, a mammogram or a colonoscopy," says Dr. Vege.
"For people with a first-degree relative with pancreatic cancer — particularly if they have two first-degree relatives with pancreatic cancer — we are doing some sort of screening with MRI every year," says Dr. Vege. "And maybe an endoscopic ultrasound every three years."
But for people with no family history of pancreatic cancer, screening isn't available.
Drs. Truty and Vege and other researchers at Mayo Clinic are mining patient data for clues that could help them develop guidelines for pancreatic cancer screening. "We are looking at the data on patients with new onset diabetes diagnosed with pancreatic cancer," says Dr. Vege. "For those who also had indigestion, abdominal symptoms, and high CA19-9 levels, we add blood sugar levels from the previous three years and we can develop an estimate of risk of about 50% to 74%."
Mayo Clinic is participating in the National Cancer Institute Pancreatic Cancer Detection Consortium to develop and test new ways to detect early stage pancreatic cancer for use in identifying people at high risk of developing pancreatic cancer.
- Treatments and outcomes are improving.
For patients whose pancreatic cancer has already spread to other organs at diagnosis, chemotherapy is the primary treatment. Patients whose cancer is confined to the pancreas may also be candidates for radiation and surgery.
If a patient's tumor doesn't involve any significant blood vessels or critical veins and arteries, patients typically undergo an operation to remove the tumor. "We've been doing that for several decades," says Dr. Truty. "Unfortunately, the long-term outcomes have been poor. A significant portion of those patients develop early recurrent disease at distant sites, meaning that the cancer had already spread and we just weren't aware of it."
To determine if surgery is the best option, Dr. Truty now considers three questions:
- Is there any evidence that the cancer has spread?
- Can the tumor be removed without leaving any cancer cells behind?
- Is the patient at a level of fitness to tolerate the surgery and recover well enough to receive chemotherapy?
"We know patients who undergo an operation to remove their tumors can live significantly longer than patients who do not have an operation," says Dr. Truty. "But if we do the surgery and leave cancer cells behind or the patient has complications and can't tolerate chemotherapy, we negate the benefit."
Dr. Truty and many other pancreatic cancer care providers are now treating patients prior to surgery with a combination of chemotherapy, plus or minus radiation. They're also doing more extensive operations.
"We've expanded our criteria for patients who are eligible for surgery and we're now operating on patients whose tumors involve significant blood vessels, such as veins and arteries," says Dr. Truty. "Improved chemotherapy, appropriate radiation, and more complex operations have significantly improved long-term outcomes."
Drs. Truty and Vege are now seeing patients survive four to six years with this combination of treatments. "The goal is to extend a patient's life and maintain or improve their quality of life," says Dr. Truty. "That's the outcome any cancer patient wants, and we're trying to get them there using all the tools we have."
Watch Dr. Truty and Dr. Vege discuss pancreatic cancer in this "Mayo Clinic Q&A" podcast video: