Doron Levin, contributing to Fortune on Tuesday, revealed Jobs' unpublicized flight to Switzerland from 2009. The details were shared off the record, by Apple director Jerry York, who died in March of 2010.
Jobs allegedly went to the University of Basel for an "unusual radiological treatment" for neuroendocrine cancer. Experts say the five-year survival rate for such cancer is between 55 percent and 57 percent -- a rate much improved from when Jobs was originally diagnosed with cancer in 2004.
"York told me about the treatment, which was not available in the U.S., in the context of our discussions about Jobs, his health and Apple's future," Levin wrote. "Under our agreement at the time, York wanted the facts of Jobs's treatment in Switzerland to remain out of the news. He didn't say whether the board knew of it. (With York's death, the off-the-record agreement is no longer in place.)"
Jobs did not reveal the reason for his medical leave of absence this week, but he issued a note to employees in which he said he will remain the company's chief executive and will be involved in all major strategic decisions in his time away. Jobs also reiterated his belief that his health is a private matter.
"I love Apple so much and hope to be back as soon as I can," the CEO wrote. "In the meantime, my family and I would deeply appreciate respect for our privacy."
Despite Jobs' requests, details about his health continue to emerge from a variety of sources. In 2008, a personal phone call from Jobs to a reporter with The New York Times revealed that the CEO did not have a recurrence of cancer at the time, though precise details of that conversation were kept off the record.
And in 2009, it took two months for The Wall Street Journal to uncover that Jobs had had liver transplant surgery during his time away from Apple. Soon after receiving his transplant, Jobs returned to work and led his company to its greatest success ever.
This week, an anonymous source told The New York Times that Jobs had been on a "down cycle" recently, and was looking "increasingly emaciated." That person indicated that Jobs was only coming into the office about two days per week, and would frequently eat lunch in his office rather than in the company cafeteria.
Though he is private about his health, Jobs did use his experience to push an organ donor registry in the state of California, requiring residents to accept or decline the option of becoming an organ donor when they renew their drivers licenses. And after he returned to work in 2009, Jobs publicly spoke about how he was given the liver of a person who died in a car crash in their mid-20s.
"I am alive because of their generosity," he said at an iPod-centric keynote in September 2009. "I hope we can all be that generous."