Pancreatic cancer is so difficult to treat in large part because it often isn't discovered until the disease has spread to other parts of the body. That's because in many cases there are no signs or symptoms until the cancer has reached an advanced stage. Even when there are early signs and symptoms, they are often vague, so patients tend to ignore them or doctors attribute them to another disease. For these reasons, pancreatic cancer is often known as a silent killer.

"There is not a single (symptom) that lets you home in specifically on pancreatic cancer," says Dr. Brian Wolpin, director of the Lustgarten Foundation Pancreatic Cancer Research Laboratory at Dana-Farber Cancer Institute and an associate professor of medicine at Harvard Medical School. "They tend to occur later in the disease course, so for most people a small tumor will not be symptomatic. Symptoms develop later, when the tumor is larger or has spread."

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