CUPERTINO (CBS / AP) -- Apple Inc. and the family of Steve Jobs were not saying Wednesday night what caused the death of the company's founder at age 56. However, medical experts indicated that the liver transplant he underwent two years ago was probably a sign that his cancer had returned.
Jobs managed to live more than seven years with a rare form of pancreatic cancer that grows more slowly than the common kind. But his need for the liver transplant was a bad sign that his troubles with the disease probably were not over.
The Apple founder long kept information on his illness behind a firewall, and no new details emerged immediately after his death.
However, medical experts unconnected with his care said Jobs most likely needed the transplant because his cancer came back or spread. They said his death could have been from cancer, the new liver not working, or complications from immune-suppressing medicines to prevent organ rejection.
A liver transplant can cure Jobs' type of cancer, but "if it were to come back, it's usually in one to two years," said Dr. Michael Pishvaian, a gastrointestinal cancer specialist at Georgetown University's Lombardi Comprehensive Cancer Center in Washington, D.C.
Jobs declared he was cured after surgery in 2004 for an islet cell neuroendocrine tumor, a much more treatable form of pancreatic cancer than the more common form of the disease that killed actor Patrick Swayze two years ago.
But the Apple chief never revealed whether the cancer had spread to his lymph nodes or liver, or how extensive his surgery was. Many doctors speculated he had a Whipple procedure, in which part of the pancreas, part of the small intestine and in some cases part of the stomach are removed and the digestive system is reconstructed.
"It's a big operation" and patients can have digestive difficulties long afterward, said Dr. Steven Libutti, director of the Montefiore-Einstein Center for Cancer Care in the Bronx, New York.
Several years later, Jobs was dramatically thinner and gaunt. In January 2009, he attributed those problems to a hormone imbalance and said there was a simple treatment for it. A few weeks later, he went on a medical leave and then had a liver transplant that was kept secret for two months.
Even then, Jobs would not say why the transplant was needed, though doctors said spread of his cancer to the liver was the likely explanation.
Usually transplants aren't done for people with cancer, but "there is some support for the idea that a liver transplant can be curative" for a neuroendocrine tumor as long as the cancer has not spread beyond the liver, Pishvaian said.
Average survival for people with neuroendocrine tumors that have spread is seven to eight years, and some patients have survived 20 to 30 years, said Dr. Martin Heslin, cancer surgery chief at Vanderbilt University in Tennessee.
It was not to be for Jobs.
In January, he announced his third and final leave of absence, and resigned in August.
(Copyright 2011 CBS San Francisco. All rights reserved.)
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