Blood Test Finds Genetic Mutations In Lung Cancer Patients When Tissue Tests Don't Work

lung cancer
For lung cancer patients, DNA circulating in their bloodstream can provide doctors with vital mutation information when tissue is not available. Photo courtesy of Shutterstock.

Knowing a patient has a genetic mutation can help a doctor choose the best cancer treatment, but sometimes directly testing a tumor is not always possible. What if you could simply test a patient's blood? For lung cancer patients, DNA circulating in their bloodstream will provide doctors with mutation information when tissue is not available, says Dr. Martin Reck from the Lung Clinic Grosshansdorf in Germany.

Reck presented the new research on behalf of an international team at the European Lung Cancer Conference in Geneva, Switzerland. Their large study, called ASSESS, compared the ability of a simple blood test to detect EGFR mutations versus testing the tumor itself.

EGFR or epidermal growth factor receptor mutations lead to hyperactivity and uncontrolled cell division. About 85 to 90 percent of all lung cancers are classified as non-small cell lung cancer (NSCLC), the name derived from how the cells appear under a microscope. About one in every 10 NSCLC patients in the United States and a little more than one in every three in East Asia have EGFR mutations.

Regardless of ethnicity, EGFR mutations are more often found in tumors from women who have smoked less than 100 cigarettes in their lives and have adenocarcinoma (a specific type of NSCLC). However, EGFR mutations can also be found in former and current smokers as well as other types of lung cancer.

Inaccessible Tumor Tissue

“We were really asking a question on behalf of patients,” Reck said in a press release: “Is there a valid test that can identify an EGFR mutation and give me the opportunity for superior treatment, even if my lung tumor is not accessible for bronchoscopy or a CT-guided biopsy?”  Reck and his colleagues also wanted to know whether blood results might be comparable to the “gold-standard” tissue test.

The researchers began their study by collecting 1,162 matched tissue and blood samples. The samples came from men and women patients residing in Japan and Europe. After testing, analysis, and comparison, the researchers discovered the two techniques showed an 89 percent rate of agreement. Plasma testing identified about half of the patients with EGFR mutations, compared to tissue testing, which has slightly more sensitivity.

Importantly, the researchers did not conduct their tests in some specially selected lab, but in local labs. In other words, they were aiming for real world conditions and not trying to beef up their findings with better-than-usual circumstance.

For patients who do not have accessible tumor tissue, blood testing for EGFR mutation turns out to be an imperfect but still attractive option, the researchers say. Since conducting this study, they already have improved their technique and so increased the sensitivity of these blood tests.

Join the Discussion