A patient has blood drawn for lab tests at Greensville County High School, in Emporia, Virginia, June 25, 2017, where Remote Area Medica l(RAM), a non-profit volunteer medical relief corps, provided free health care to people in remote areas of the United States. (AFP Photo/PAUL J. RICHARDS)

WASHINGTON, July 12 (Xinhua) -- U.S. researchers said Wednesday they have developed a new blood test that may help doctors correctly identify patients with early-stage pancreatic cancer, a disease often diagnosed too late for cure.

In a study published in the U.S. journal Science Translational Medicine, researchers at the University of Pennsylvania said the test, based on a pair of blood biomarkers, detected early stage of the disease in lab experiments with 98 percent sensitivity and 87 percent specificity, meaning that it accurately identified 98 percent of patients with and 87 percent of those without the disease.

"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," Robert Vonderheide, director of the university's Abramson Cancer Center (ACC), who was not involved in the study, said in a statement.

"Having a biomarker test for this disease could dramatically alter the outlook for these patients," Vonderheide said.

Currently over 53,000 people in the United States are diagnosed with pancreatic cancer -- the fourth leading cause of cancer death -- every year.

Most of the patients with pancreatic cancer are diagnosed during advanced stages of the disease, and their tumors are not surgically resectable, leading to an overall five-year survival rate of merely seven percent.

To develop urgently-needed early-detection methods, the researchers evaluated 746 cancer and control human blood samples using an inexpensive, commercially available protein-detection assay.

The team found that blood levels of plasma thrombospondin-2 (THBS2), combined with levels of a known later-stage biomarker called CA19-9, was reliable at detecting the presence of pancreatic cancer in patients.

Their results were validated in a follow-up study that analyzed samples from 197 pancreatic cance patients, 140 healthy controls, and 200 people with non-cancer pancreatic disorders.

"Positive results for THBS2 or CA19-9 concentrations in the blood consistently and correctly identified all stages of the cancer," said Ken Zaret, director of the Penn Institute for Regenerative Medicine, who led the study.

"Notably, THBS2 concentrations combined with CA19-9 identified early stages better than any other known method."

The team anticipated that the combination THBS2 and CA19-9 could serve as a low cost, noninvasive screening tool in individuals with a high risk of developing pancreatic cancer, including those who have a first-degree relative with pancreatic cancer, who are genetically predisposed to the disease, or who had a sudden onset of diabetes after the age of 50.