A new study has pointed towards the possibility of a simple blood test to detect lung cancer.
According to the study, a simple test for four blood proteins may provide a less-invasive record for patients having suspicious lesions on chest radiographs or computerized tomography (CT) scans.
The study was led by Edward Patz, Jr., M.D., a radiologist at Duke University Medical Center.
"CT scans have a very high false positive rate when trying to discover lung cancer," said Dr. Patz.
He added: "What that leads to is several follow-up imaging studies or invasive procedures like biopsy, which have risks of their own. This study is the first step in developing a test that would allow us to sample a patient's blood and determine whether more invasive testing and treatment are necessary."
Four proteins in the blood were studied by researchers and it was found that their levels were different in lung cancer patients as compared to same age and gender patients who were not suffering from cancer.
The researchers compared the levels of these proteins in the blood of almost 100 patients known to have lung cancer to the levels in the blood of nearly 100 patients without cancer.
"Using the four markers, known as CEA, RBP, SCC and AAT, we were able to distinguish patients who had cancer from those who didn't with over 80 pct accuracy," Patz said.
Though all the four protein markers have been linked to lung cancer, but none in isolation exerts enough influence to definitively indicate the disease. However, in combination they may be very useful, Patz said.
In order to sort out a person's chances of having lung cancer, based on the levels of each of the four proteins a "classification tree" was created by the researchers.
"People whose samples landed in one of three bins at the bottom of the tree had a 90 pct chance of having cancer. Other bins indicated risks as low as 10 pct," said Patz.
For routine lung cancer screening, CT scanning has been proposed, but it detects many non-cancerous nodules, leading to more invasive and risky treatment.
A recent study found that nodules were detected in more than 70 pct of those screened, while lung cancer was found in less than three pct.
"We talk about how devastating this disease is all the time, but we still don't have a screening system in place that can detect lung cancer early, without exposing patients to the risks of biopsy and surgery. This study is an important step in the right direction," said Patz.
The researchers plan to conduct a larger study examining the use of biomarkers probably in patients found to have lung lesions by CT scan.
Eventually the aim is to develop a screening system through which patients could have the blood test before imaging and those found to be in a "high risk bin" would have a CT scan for further examination.
"We would determine whether the person is at low or high risk of having lung cancer based on these biomarkers. Patients at low risk might be followed with further blood tests or imaging studies while those at high risk might require immediate intervention," he said.
The researchers published their findings in the Journal of Clinical Oncology.