Blood tests can now spot early pancreatic cancer
Typically, pancreatic cancer is only discovered when the tumours are already too large to treat.
By the time pancreatic cancer is detected, it is so severe that four out of five people will die after diagnosis, but a new blood test may accurately detect pancreatic cancer in its early stages. This discovery offers new hope for people at risk of this fast-moving and often fatal disease, researchers said.
Pancreatic cancer affects the pancreas, a gland which is located in the upper abdomen. Pancreatic cancer is often referred to as the “silent disease” because symptoms are few and non-specific, mostly leading to late diagnosis.
Cancer of the pancreas tends to affect people over the age of 50, and most sufferers are aged 65 to 80 at the time of diagnosis. Men are at slightly higher risk than women.
One of the deadliest cancers
More than 53 000 people in the United States are diagnosed with pancreatic cancer annually. It is the fourth leading cause of cancer death. While statistics provided by the Cancer Association of South Africa (Cansa) may not be the leading cause of death through non-communicable disease in South Africa, the survival rate is still at a low of 20%, although survival is on the increase through the advance of medical technology.
"A long-standing concern has been that patients with pancreatic cancer are often not diagnosed until it is too late for the best chance at effective treatment," said study co-author Robert Vonderheide, director of the Abramson Cancer Center at the University of Pennsylvania. "Having a biomarker test for this disease could dramatically alter the outlook for these patients."
Biomarkers in blood can detect pancreatic cancer
Using stem cell technology to create a cell line from a patient with advanced pancreatic ductal adenocarcinoma, researchers were able to turn back the clock on the progression of the disease. In doing so, they found a pair of biomarkers (or identifiers) in the blood that picked up pancreatic cancer in human cancer cells at different stages of tumour growth.
"Genetically reprogramming late-stage human cancer cells to a stem cell state enabled them to force the reprogrammed cells to progress to an early cancerous state, revealing secreted blood biomarkers of early-stage disease along the way," said a summary of the report, published in the journal Science Translational Medicine.
One biomarker known as plasma thrombospondin-2 (THBS2), combined with a known later-stage biomarker called CA19-9, "consistently and correctly identified all stages of the cancer," said lead author Ken Zaret, director of the Penn Institute for Regenerative Medicine.
"Notably, THBS2 concentrations combined with CA19-9 identified early stages better than any other known method. "The test could be done with an inexpensive, commercially available protein-detection assay, researchers said.
Further work needed
In principle, the test could be applied right away, though researchers cautioned they want to do further work "to be absolutely certain of the cutoff values that we have for what is a significant or likely call for disease," a spokeswoman said in an email. "Some more work will be needed but in general the test and concept could be applied," she said.
A key population for the test would include people with a family history of pancreatic cancer, those with a genetic predisposition to the disease, or who had a sudden onset of diabetes after the age of 50. Earlier this year, a separate team of researchers in the United States and China unveiled a new blood test for detecting pancreatic cancer. That method involved finding a protein dubbed EphA2 found in pancreatic tumours, according a report in the journal Nature Biomedical Engineering.