Blood test for pancreatic cancer shows promise


Pancreatic cancer is one of the most lethal tumour types because it's too often diagnosed in a later, advanced stage, but a new study suggests that a simple blood test may help spot the disease earlier.

The study is described as small and preliminary and investigators cautioned that the initial findings would need to be confirmed in larger trials.

The study co-author, Dr Nita Ahuja, an associate professor of surgery in the Department of Oncology and Urology at the Johns Hopkins University School of Medicine in Baltimore said: "Pancreas cancer is the fourth leading cause of cancer death in the United States".

"There have been minimal to no improvements in the survival from this disease in the last 40 years. More than 40 000 people are diagnosed every year and about the same number die.

Surgical removal

"One of the main reasons for the lethal nature of this cancer is that most cancers are diagnosed too late once they have spread to other organs," Ahuja said.

"About 8% have spread to distant organs such as the liver or lungs, while another 10% have locally spread to major blood vessels. 

"In patients where cancer can be detected early and it hasn't spread, a long-term cure is possible with surgical removal of the cancer with the surrounding lymph.

However, in the patients where cancer can be detected early and has not spread, a long-term cure is possible with surgical removal of the cancer with the surrounding lymph."

Any means of spotting the cancer early would therefore be crucial, Ahuja added.

Search  for signs

"We have mammograms to screen for breast cancer and colonoscopies for colon cancer, but we have had nothing to help us screen for pancreatic cancer," she said.

The new study sought to find blood "markers" for pancreatic cancer "in patients who are at increased risk for developing this cancer, such as [those with a] family history or heavy smokers."

Ahuja's team had previously identified mutations in two genes, called BNC1 and ADAMST1, that typically occurred in the presence of pancreatic cancer.

Since both mutations are found in 97% of early stage pancreatic cancer tissues, the researchers developed tests to search for signs of the mutations in blood samples collected from 42 people already diagnosed with early stage pancreatic cancer.

Reporting in the online edition of the journal Clinical Cancer Research, Ahuja's team said both genetic markers were found in 81% of the tested blood samples, but not in samples taken from patients who either did not have pancreatic cancer or had a history of pancreatitis (an inflamed pancreas).

High risk

The researchers said the results were much more impressive than, for example, the prostate-specific antigen (PSA) test used to screen for prostate cancer, which has roughly a 20% success rate.

Ahuja said, though, that an 81% accuracy rate was "far from perfect."

The test also had a false-positive rate of 15%, meaning that 15% of people who get the test initially will be told they might have pancreatic cancer when that is not the case.

Ahuja stressed that the test is not designed as a screen for the population as a whole -- only for those already deemed to be at high risk for the disease.

"The eventual goal is to develop a cost-effective test to analyse patients who are at high risk," she said.

"The beauty of this test is that it can be repeated every year as you go for your annual physical."

More information

Find out more about pancreatic cancer at the Pancreatic Cancer Action Network.

Photo about blood sample from Shutterstock.

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