How Old Is Your Cancer? Pancreatic tumors can germinate for a decade before turning deadly, raising hopes for early detection

reposted from: SciAm Jan 2011
highlights by crabsallover

How Old Is Your Cancer? Pancreatic tumors can germinate for a decade before turning deadly, raising hopes for early detection

A patient who receives a diagnosis of pancreatic cancer has only a 5 percent chance of surviving for five years, a harrowing prognosis that scientists have long struggled to understand. Part of the problem, new research suggests, is that the disease is not typically diagnosed until 15 years after the first cancer-causing mutations appear, by which point the cancer has spread and become highly aggressive.

The findings indicate that there may be plenty of time for doctors to intervene before pancreatic cancer becomes lethal—an exciting prospect given recent advances in diagnosing the disease early, when it can be successfully removed with surgery and chemotherapy.

In research published recently in Nature (Scientific American is part of Nature Publishing Group), scientists at Johns Hopkins University sequenced the genomes of seven people who had died of late-stage pancreatic cancer. Their tumor cells contained different types of mutations that the scientists traced back in evolutionary time using mathematical models to build a kind of “family mutational tree.” The models suggested that cancer cells appear 10 years after the first cancer-causing mutation arises and that another five years pass before the cancer cells spread and become deadly.

The findings question “the pervasive belief that pancreatic cancer is so aggressive and grows so quickly that screening cannot be effectively used,” says study co-author and Johns Hopkins pathologist and oncologist Christine A. Iacobuzio-Donahue.

In the past two years scientists have brought screening techniques for pancreatic cancer closer to reality. In February 2010 researchers at the University of California, Los Angeles, compared RNA found in the saliva of 60 treatable pancreatic cancer patients with the saliva of 30 cancer free individuals and identified four RNAs that together could correctly identify the cancer 90 percent of the time. And in March 2009 Northwestern University researchers publishing in the journal Disease Markers developed an optical technology that recognizes various stages of pancreatic cancer cells with 95 percent sensitivity. The technique uses light scattering to detect changes in the cells of the duodenum, part of the small intestine adjacent to the pancreas, which can be viewed using minimally invasive endoscopy. These technologies are not yet available commercially, but early detection using optical tests and blood or saliva analyses should “advance measurably in the next decade,” says David Tuveson, an oncologist at the Cambridge Research Institute in England. Until then, he notes, doctors should consider using current techniques such as CT and MRI scans to screen patients who are at high risk because of family history of the disease. “Recall that our Supreme Court Justice Ruth Bader Ginsburg had a small pancreatic cancer diagnosed in January 2009 when she was undergoing a CT scan,” Tuveson says. One month later doctors removed it successfully and discharged her with a clean bill of health. —Melinda Wenner Moyer

Animal fats pancreas cancer link

reposted from: http://news.bbc.co.uk/1/hi/health/8119093.stm

Eating a diet high in red meat and dairy products is linked to an increased risk of pancreatic cancer, a US study has suggested.

Researchers followed 500,000 people who had completed a food diary for an average of six years.

The Journal of the National Cancer Institute paper found those who had the most animal fats in their diet had a higher risk of developing the cancer.

UK experts said cutting down on the fats was a way of reducing risk.

There has previously been confusion over whether there was a link between animal fats and pancreatic cancer, with different studies reaching opposite conclusions.

About 7,000 people are diagnosed with pancreatic cancer in the UK each year, with smoking being the biggest risk factor.

The prognosis is poor - the time between diagnosis and death is usually about six months.

'Welcome addition'

This latest research was carried out by the National Cancer Institute in Bethesda, Maryland, which felt earlier studies had been too small to give reliable results.

The participants were being followed to see if they developed a range of diseases.

This large study adds to the evidence that pancreatic cancer is more common in people who eat too much fat, particularly saturated fat  Josephine Querido, Cancer Research UK

Of the half a million studied, 1,337 developed pancreatic cancer.

Men who consumed the highest amount of total fats had a 53% higher relative rate of pancreatic cancer compared with men who ate the least.

In women, there was a 23% higher rate of the disease in those eating the most fat compared with those who ate the least.

Overall, people who consumed high amounts of saturated fats had 36% higher relative rates of pancreatic cancer compared with those who consumed low amounts.

Writing in the Journal of the National Cancer Institute, the researchers led by Dr Rachel Stolzenberg-Solomon, said: "We observed positive associations between pancreatic cancer and intakes of total, saturated, and monounsaturated fat overall, particularly from red meat and dairy food sources.

"We did not observe any consistent association with polyunsaturated or fat from plant food sources.

"Altogether, these results suggest a role for animal fat in pancreatic carcinogenesis."

In an editorial in the journal, Dr Brian Wolpin, of the Dana Farber Cancer Institute in Boston, and Dr Meir Stampfer, of the Harvard School of Public Health, said the study was a "welcome addition to the understanding of a disease that is in great need of new insights".

Josephine Querido, senior science information officer for Cancer Research UK, said: "This large study adds to the evidence that pancreatic cancer is more common in people who eat too much fat, particularly saturated fat.

"Understanding ways of reducing the risk of pancreatic cancer is very important because it can be very difficult to treat.

"Apart from stopping smoking, the best way to reduce your risk of cancer is to eat plenty of fruit vegetables and fibre, and to cut down on fatty foods, red and processed meat and limit your intake of alcohol."