It then takes another 6.8 years, on average, for that cell to develop into a plum-sized cancerous tumor, after which at least one tumor cell develops the ability to spread to other organs. Once the cell spreads, patients die an average of two and a half years later.
"The science [in the study] is exquisite," said Dr. J. Leonard Lichtenfeld, deputy chief medical officer of the American Cancer Society in Atlanta. "The researchers were able to make the point that what we know as cancer is really the end stage of a very long process."
In its early stages, cancer of the pancreas -- the gland that aids digestion and helps control blood sugar levels -- causes vague symptoms or none at all. That's why people are typically diagnosed after the cancer has spread beyond the pancreas, and why the disease is often fatal. This year, pancreatic cancer will cause about 36,800 deaths, according to the U.S. National Cancer Institute.
Because people with pancreatic cancer typically die within a year of diagnosis, it may seem as if this form of cancer progresses rapidly, said Iacobuzio-Donahue.
"But what we've learned is that it is actually a long, slow process, and metastasis happens at the very end, within the final two to three years. Before that time, there is a tremendous window of opportunity for screening," she said. "We just have to modify our screening methods to better diagnose people at an earlier time point."
In the future, new imaging techniques and blood tests will offer hope for early detection, the study noted. And just as people have a colonoscopy when they turn 50, "perhaps they should have an endoscopy of their upper gastrointestinal organs that includes an ultrasound of the pancreas," said Iacobuzio-Donahue. Screenings for colon and breast cancers are based on age
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