When Apple founder Steve Jobs passed away earlier this year, millions of people around the world read that he died of pancreatic cancer. However, that's not truly accurate. There are several types of pancreatic cancer — the fast growing and the slow growing.
The fast-growing or adenocarcinoma is more common and originates from cells that line channels within the gland. The slow-growing kind or neuroendocrine cancer arises from other cells in the pancreas.
Technically, Jobs suffered from a neuroendocrine tumor that occurred in the pancreas — a glucagonoma. A glucagonoma is a very rare tumor of the islet cells of the pancreas that over-secretes glucagon, a hormone that raises blood sugar.
Though Jobs' type of cancer was quite rare, neuroendocrine tumors in general are not as rare a one would assume. In fact, their incidence rate has continued to grow over the past three decades.
Neuroendocrine tumors now comprise the largest non-colorectal gastrointestinal tumor population, with about 110,000 existing cases at any one time in the United States
So how does this cancer happen? A neuroendocrine tumor begins in the hormone-producing cells of the body's neuroendocrine system. Neuroendocrine cells are widely distributed throughout the body, and they control specific functions, such as regulating the air and blood flow through your lungs and controlling how quickly food moves through your gastrointestinal tract.
Cancer occurs when normal cells mutate and begin to grow uncontrollably, resulting in a mass. In the case of neuroendocrine tumors, they are more likely to arise from areas where neuroendocrine cells are concentrated. This includes the pituitary, thyroid and adrenal glands; the lungs; and the gastrointestinal tract. The latter tumors are the most common, and they encompass the pancreas and the luminal intestinal tract.
Men are more likely to develop neuroendocrine cancers than women, and they commonly occur between the ages of 40 to 60. Research suggests the cancers may be hereditary, although both arsenic and sun exposure have been linked to Merkel cell cancer, a type of neuroendocrine cancer that develops on or just beneath the skin and in hair follicles.
Symptoms vary, and are often mistaken for other milder illnesses. Patients may experience frequent diarrhea, stomach cramps, unexplained weight changes, skin flushing, breathing problems and a rapid heartbeat. Because these tumors tend to grow slowly, these symptoms are often mild at first and may be overlooked or ignored.
In addition, these tumors can cause extremely high levels of the hormones epinephrine and norepinephrine — also known as adrenaline and noradrenaline. These hormones are responsible for giving the body an energy boost in times of stress, so patients may experience symptoms such as high blood pressure, a fast pulse and heart rate, palpitations or anxiety attacks.
The treatment for these cancers varies considerably on factors such as size and location, metastasis and overall health of the patient. But the good news is that despite the unfortunate passing of Jobs, a prognosis is not necessarily a death sentence. Treatment may encompass surgery, radiation, and chemotherapy or other drugs. As these cancers receive more attention and funding for research, better treatments and cures are being developed.
Dr. Lowell Anthony is a professor of medicine and neuroendocrine medical oncologist at the UK Markey Cancer Center.