DNA blood tests can take over standard tests in detecting lung cancer mutations
An international group of researchers reported at the European Lung Cancer Conference (ELCC) in Geneva, Switzerland, that cancer DNA circulating in the bloodstream of lung cancer patients can provide doctors with vital mutation information that can help optimize treatment when tumor tissue is not available.
Sometimes, tumors are not available for testing via standard methods of testing like bronchoscopy or CT-guided biopsy. So, testing for the presence of mutations in the tumor itself is not always possible. Hence, the large international ASSESS study aimed to compare the ability of blood testing to detect EGFR mutations with the more standard method of testing the tumor itself.
The tests in this study were performed in local labs that are used for daily clinical routine. They were not conducted in specially selected central labs, because they aimed to reflect clinical reality and not a ‘virtual’ trial reality. On the whole, study included 1162 matched tissue and blood samples. There was an 89% rate of agreement between the blood test and tissue test according to the comparison of the outcomes of EGFR testing. Plasma testing identified about half of the patients with EGFR mutations, compared to tissue testing.
These results have important implications for the use of cancer therapies that target specific cancer mutations. They validate that the presence of EGFR mutations in circulating DNA from plasma or serum can be detected in around half of the patients. Patients, who do not have accessible tumor tissue, can go in for plasma testing for EGFR mutation. This might help offer them adequate targeted treatment.
Dr Rafael Rosell, an expert on the ESMO Faculty on Lung cancer remarked, “Cell-free DNA detected in the bloodstream of cancer patients represents an excellent tool to examine genetic alterations that are usually found through tumor tissue testing. This represents one of the most astonishing phenomena in biology.”
Since the study, there has already been an improvement in techniques that has lead to an increase in sensitivity of tests for EFGR mutations in circulating tumor DNA. This study paves the way for further studies and expands the routine use of examining mutations such as EGFR mutations as part of cancer patient care.
