Some cancers—particularly lung cancer—are often detected incidentally, after unrelated medical exams. In many cases, it is difficult to tell the malignant from benign tumors, except by using invasive methods such as a biopsy. However, one blood test that can rule out cancer may be the game-changer that we require.

Recent data indicate that currently, in the United States, around 1.6 million pulmonary nodules per year are detected that require further testing to ascertain whether they are cancerous.

Biopsies are invasive. And, often, health-care practitioners will advise even more invasive solutions, such as surgery, to remove the nodules and the patient's doubts.

For such sensitive, fragile organs as the lungs, however, an invasive method brings with it a whole set of risks that can potentially make matters worse.

Dr. Gerard Silvestri, of the Medical University of South Carolina in Charleston, led a study to explore a noninvasive method of determining whether lung nodules are benign or malign. He explains why this research is important.

"Think of your lung as a 2-liter bottle of soda, and the nodule as a pea in the center of it," notes Dr. Silvestri. "During a biopsy, for example, the lung could collapse and need a tube to expand it," he explains.

That is why he and a team of researchers have explored the merits of a blood test focusing on the presence of biomarkers that would indicate how likely it is that the detected nodules are cancerous.

"Our goals for this biomarker are to help calculate the risk of cancer, present the patient with options and recommendations, and avoid subjecting patients with benign disease to expensive, unnecessary, and intrusive procedures."

–Dr. Gerard Silvestri

The results of their research have now been published in the journal Chest.

Test demonstrates accuracy of 98%

Dr. Silvestri and team's research is part of the Pulmonary Nodule Plasma Proteomic Classifier study, which the study authors call "a prospective, multicenter, observational study" that retrospectively evaluates the effectiveness of a specially designed blood test that can evaluate "two [telling] proteins and five clinical risk factors" for lung cancer.

The blood test's purpose is to determine whether patients with lung nodules who have a low or moderate risk of lung cancer are likely to have developed harmless or malign tumors.

The main biomarkers that the test assesses are the proteins LG3BP and C163A, the plasma concentrations of which predicts this type of cancer.

If the test results are negative and the person being tested has a lung cancer chance of under 50%, the possibility of cancer is very reduced. In this case, health-care practitioners can devise an appropriate treatment plan and follow-up routine.

"It serves as a 'rule out' test for those with low to moderate risk," Dr. Silvestri says of the blood test.

"The biomarker is a tool," he continues, "to help calculate the general risk of cancer and present a patient with recommendations and options. It can push people out of indeterminate risk and into low risk—without having to undergo invasive and potential risky procedures."

The results of the current study indicated that the blood test was 98% effective in ruling out the possibility of lung cancer.

For added certainty, however, patients with negative results—and thus with a low likelihood of malign tumors—would still be monitored periodically to make sure that no errors were made.

"A low-risk tumor," Dr. Silvestri goes on to say, "will be followed with serial imaging. After 2 years of [computed tomography] scans being performed periodically and without evidence of growth, we can say it's benign."

For this study, the researchers retrospectively evaluated the data of 685 clinical trial participants of 40 years or older, all of whom presented with newly detected lung nodules at baseline.

The specialists suggest that, had the blood test they studied been used to inform patient care, 40% fewer invasive procedures would have taken place in the case of people with harmless nodules.

Taking this into account, Dr. Silvestri and colleagues say that the next step from here should be to conduct a "clinical utility study to assess how clinical decision-making and use of invasive procedures are altered with knowledge of the results of [the recently studied] test."

"Anything to provide physicians with more confidence in how they would manage patients would be helpful," concludes Dr. Silvestri.