What Causes Pancreatic Cancer, and How Is It Treated?

Maria Menounos is opening up about her experience with pancreatic cancer, saying that she still hasn't "come to grips with it all." The 44-year-old shared information about her experience on Instagram, pointing out that "so very few even survive pancreatic cancer."

In an interview with People, Menounos said she was first diagnosed with type 1 diabetes last year after experiencing severe leg cramps. But while she briefly felt better, she soon began having "excruciating abdominal pain coupled with diarrhea." Menounos said she was told "everything's fine," but her symptoms continued — and got worse. She finally did a whole-body MRI, which found a nearly four-centimeter mass on her pancreas. In January, she was diagnosed with a stage 2 pancreatic neuroendocrine tumor, a form of cancer.

Menounos, however, isn't the first celebrity to experience a pancreatic-cancer diagnosis. Willie Garson, Jerry Springer, and Alex Trebek have all died from the disease over the past few years. But what causes pancreatic cancer, and what are the symptoms? Here's what you need to know.

Pancreatic cancer is a form of cancer that starts in the pancreas, an organ that sits behind the stomach, according to the American Cancer Society (ACS). Pancreatic cancer happens when cells in the pancreas start to grow out of control.

But there are different forms of pancreatic cancer, and the prognosis varies for each, says Russell C. Langan, MD, associate chief surgical officer and director of surgical oncology, Northern Region at RWJBarnabas Health and Rutgers Cancer Institute of New Jersey.

A pancreatic neuroendocrine tumor, which Menounos had, "is the second most common cancer of the pancreas," Dr. Langan says. But it is handled differently than what's traditionally thought of as pancreatic cancer, or pancreatic ductal adenocarcinoma, the most common cancer in the pancreas, he explains.

It's not known exactly what causes pancreatic cancer, but there are some known risk factors. According to the ACS, those include:

Symptoms of pancreatic cancer don't usually start until the disease is in more advanced stages, Dr. Langan says. However, once symptoms start, the Mayo Clinic says they can include:

Like most forms of cancer, there are stages to pancreatic cancer that range in severity and mass size. The National Cancer Institute (NCI) breaks them down:

"Unfortunately, a lot of times pancreatic cancer is diagnosed at late stages because there is really no good screening program that's able to detect early pancreatic cancer," says Wael Harb, MD, a hematologist and medical oncologist at MemorialCare Cancer Institute at Orange Coast Medical Center in Fountain Valley, CA.

Mary Dillhoff, MD, a surgical oncologist at The Ohio State University Comprehensive Cancer Center, says the lack of screening is a "question we encounter frequently" with patients. "At this point, we don't have the mammogram or colonoscopy equivalent for pancreas cancer," she says.

Sometimes a patient's pancreatic cancer will be picked up on a CT scan for something else, Dr. Harb says. "But most typically what I see is a patient developing symptoms who is already in an advanced stage," he adds.

Pancreatic cancer has a high mortality rate. The overall five-year survival rate for the disease is just 12 percent, according to the American Cancer Society. However, patients with a localized form of pancreatic cancer may see survival rates up to 44 percent, the organization reports.

"No matter what the prognosis is, we don't know how that particular person will do with treatment," Dr. Dillhoff says. "I try to refocus on them. How they do and how their response to chemotherapy is more important than us trying to make predictions about how long they might live based on data. We still have hope on an individual level."

Dr. Langan says that overall prognoses for pancreatic cancer are improving, though. "For a very long time, the average survival for pancreatic cancer was two years," he said. "The five-year survival when I first started was 4 percent for all comers. Clearly, we have a long way to go, but it has increased."

Pancreatic cancer is usually treated with one or several of five options, the NCI says, including surgery, radiation therapy, chemotherapy, chemoradiation therapy, and targeted therapy.

Pancreatic cancer can be cured if it's found early, Dr. Harb says. "Once it's metastatic, spread outside the pancreas to other organs, it's not curable," he adds.

"Although the majority of patients will not reach cure, it is always something we strive for," Dr. Langan says. "It really has to be a multimodal therapy to offer patients the chance of long-term survival." He underscores the importance of hope with pancreatic cancer. "You have to hold onto hope," he says. "Myself and others that treat this disease really stress this."