Rarity of Steve Jobs' cancer and treatment provides few predictions and few options
Like everything else about him, Steve Jobs' medical history has been singular -- an uncommon treatment for a very rare cancer -- so it's tough to predict his fate.
But experts suggest that he's run out of good fixes. If the cancer has returned, he's not a good candidate for a second transplant. Drugs can prolong survival, but they don't cure.
Neither Jobs nor the company has revealed any details of his condition, and none of his doctors is discussing his care. But the iconic tech visionary announced his resignation Wednesday, saying he "could no longer meet my duties and expectations as Apple CEO."
To be sure, Jobs has defied predictions before. In his 2005 speech at Stanford University's commencement
ceremony, he recalled doctors telling him "this was almost certainly a type of cancer that is incurable and that I should expect to live no longer than three to six months." A later analysis found it to be a rare and more treatable type.
In 2009, Jobs rocked the tech world, revealing he had a liver transplant after being diagnosed with a pancreatic neuroendocrine tumor.
Photos taken last February for the National Enquirer showed him looking "skeletal" and "near death" outside Stanford's Cancer Center -- yet only two weeks later, he joined President Barack Obama and the valley's tech titans at venture capitalist John Doerr's sprawling estate in Woodside.
The average three-year survival rate for people with Jobs' condition
who receive a liver transplant is about 70 percent, said Dr. William C. Chapman, chief of the Abdominal Transplantation Section at Washington University School of Medicine in St. Louis.
By five years, about half are still alive, said Chapman and Dr. Simon Lo, director of pancreatic and biliary diseases at Cedars-Sinai Medical Center in Los Angeles.
But there's not much data -- and there's hardly any information at all -- for 10-year survivors.
Only 185 liver transplants were performed for metastatic neuroendocrine tumors in the United States from November 1988 to March 2011. The overall five-year survival rate was 57.8 percent, according to an analysis of the United Network for Organ Sharing database by Baylor surgeon Dr. Christine O'Mahony.
While a transplant occasionally provides a cure, it prolongs survival and eases symptoms only "in a very small subset of patients," favoring those younger than 50, she concluded. Jobs is 56.
"The challenge is that there is a relatively small number of patients who undergo a transplant" for Jobs' type of cancer, Chapman said. "It makes interpretation difficult -- until you have a large series of patients, it becomes anecdotal.''
Lo agreed. "It's a rare condition," he said. "And many places don't consider transplants to be the standard of care. Some consider it semi-experimental. ... So you have a small number of patients, whose individual experiences skew the data."
Neither expert has direct knowledge of Jobs' health, but both agreed that technical problems related to the liver transplant are less common two years after surgery.
Liver transplants work well when the cancer originates in the liver because there is the possibility that it's confined there -- and once it's removed, the patient can be cured, Chapman said.
But if the cancer has started elsewhere -- Jobs' started in the pancreas -- then metastasized to the liver, "there is a greater risk that outside the liver it can recur," he said.
The cancer returns in about half of patients, according to two European studies. In a German study, cancer returned in 7 of 12 transplant patients; in a French study of 31 transplant patients, about half died from cancer.
Repeat transplants are sometimes performed for technical problems, such as vascular thrombosis or chronic rejection, Chapman said.
"In general, it's pretty uncommon to perform a transplant for recurrence of malignancy," Chapman said. That's because if it has returned to the liver, it's more likely to return to other places, too.
"When you're dealing with a cancer that has metastasized, it means it might be hiding somewhere else in the belly," Lo said.
And immune-suppressing drugs reduce resistance, he said, "so there is always worry that the cancer could be encouraged to grow."
There are new drugs to treat the type of tumor that Jobs has -- and prevent transplant rejection. But one of the drugs can create lung or breathing problems, infections and renal failure, leading to death; the second can cause liver problems. Neither agent is proven to cure cancer.
But because medical studies have so few patients with this rare disease, and even fewer get transplants, a precise forecast is impossible, experts said.
Doctors use the abbreviation "N" to symbolize the sample size of a study to identify trends. When it comes to Steve Jobs, said Stanford bioethicist Hank Greely, "As in so many other ways, Jobs is N=1."
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Steve Jobs' cancer and treatment 2011
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