"The first two things I would think about is one, some kind of unusual latent complications from his surgery, or two, does it have anything to do with active islet cell tumor that has to do with the hormone imbalance," Ko said.
Jobs announced in 2004 that he had undergone successful surgery on his pancreas for the less aggressive form of pancreatic cancer, called islet cell neuroendocrine tumor.
Ko says one common treatment, called a Whipple procedure, involves removing a section of the pancreas along with the tumor.
"Individuals can have some difficulty digesting and absorbing food because pancreas is responsible for producing enzymes that help us break down fats and proteins and things like that," Ko said.
But those symptoms typically become apparent shortly after surgery.
Jobs' explanation of a hormone imbalance, which can affect absorption of nutrients, could also suggest other scenarios, such as a return of the cancer.
"Yes, there has been a lot of speculation are his symptoms related to tumor recurrence; while none of us knows with any certainty, it sounds as though his doctors have run a number of tests beyond the sophisticated blood tests he mentions in his letter," Ko said.
Ko was clear that he has no direct information regarding Steve Jobs, but he says in cases where islet tumors do reappear, they can be treated effectively with new drugs, some of which can be taken orally, or injected by the patient themselves.
