Jobs was reportedly treated in 2004 for a pancreatic neuroendocrine tumor.

Jobs was reportedly treated in 2004 for a pancreatic neuroendocrine tumor, a rare form of pancreatic cancer. Neuroendocrine tumors make up less than 5 percent of all pancreatic cancers, according to PCAN.

Pancreatic cancers come with a very low survival rate: 75 percent of patients die less than a year after diagnosis, and 94 percent die within five years, according to PCAN.

 

What is it about pancreatic cancer that makes it so lethal?

"There is no early detection method for pancreatic cancer — the cancer is usually diagnosed only after it has metastasized," Fleshman said.

Symptoms, which often don't occur until the disease is in its advanced stages, include upper abdominal pain, loss of appetite, and weight loss — all of which can also be caused by other diseases and conditions, according to the Mayo Clinic.

"The early symptoms are very non-specific," Fleshman said. "It's often not until a patient has become jaundiced that most physicians look deeper."

Only 8 percent of cases are diagnosed before the cancer has spread beyond the pancreas, according to the National Cancer Institute. In these patients, 21.5 percent are predicted to survive 5 years. The survival rate is lower for patients diagnosed at later stages — less than 2 percent of patients diagnosed once their cancer has spread to other parts of the body survive 5 years.
The pancreas lies deep within the abdominal cavity — even a CT scan may not spot a tumor within the organ, Fleshman.

Surgery is only an option for the 15 percent of patients whose cancers have not metastasized outside of the pancreas at the time of their diagnosis, Fleshman said.

Moreover, chemotherapy is often ineffective at killing pancreatic cancer cells, leaving patients with few options.

People with the type of tumor Jobs reportedly had have a better survival rate than most other pancreatic cancer patients: About 42 percent are alive five years after their diagnosis, according to the PCAN. The reason may be that the cells of a pancreatic neuroendocrine tumor multiply more slowly than the tumor cells of the more common adenocarcinomas, Fleshman said.

The National Cancer Institute (NCI) estimates that 43,000 new cases of pancreatic cancer were diagnosed in 2010, and nearly 37,000 people died of the disease. About 20 percent of cases occur in people between the ages of 55 and 64.

Pass it on: As a group, pancreatic cancers have a poor prognosis because they are often not detected until the late stages of the disease and usually resistant to chemotherapy