SAN FRANCISCO - Steve 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 a liver transplant two years ago 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, experts unconnected with his care say Jobs most likely needed the transplant because his cancer returned 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.

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.

Several years later, Jobs was 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.

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 have survived 20 to 30 years, said Dr Martin Heslin, cancer surgery chief at Vanderbilt University.

It was not to be for Jobs.

In January, he announced his final leave of absence, and resigned in August.

Associated Press