The Food and Drug Administration (FDA) just approved the first blood-based test to detect lung cancer mutations (gene changes). This is the first approval in what has been an exploding field of research that many are calling “liquid biopsies”. The reason for studying liquid biopsies is pretty obvious to most lung cancer patients. Getting a normal biopsy (where tissue is taken from the tumor to see if there is cancer) can be an invasive procedure. Many people don’t want more than one biopsy but doctors and scientists need more information to understand how to best treat the cancer at different times during therapy.
In addition, sometimes not enough tissue is able to be collected to do all the appropriate tests. If the tests could be done by simply taking blood, urine, sputum or even breath samples, it would make testing much easier for patients.
This technology will not replace a tissue biopsy to diagnose a cancer and determine what type (non-small cell or small cell) or stage your cancer is. However, it may help with treatment decisions, particularly when deciding whether to take Targeted Therapies for your lung cancer. For example, the newly approved test detects certain changes in a gene called EGFR (Epidermal Growth Factor Receptor) and can determine whether the patient is a good candidate for the drug Tarceva (erlotinib).
There are many different companies developing liquid biopsy tests in many different ways. The most common type of test uses blood from a patient and looks at pieces of DNA that have been released into the blood by the cancer cells. (This is similar to blood-based prenatal testing where they can look at both the baby’s DNA and the mother’s DNA in the mother’s blood.)
The technology tends to work best in advanced disease (where there is more cancer) and metastatic disease (when it is already spreading through the body) because there is more cancer DNA in the blood. Because of this, right now liquid biopsies are mostly being used for treating and “monitoring” advanced disease and re-testing after cancers recur. For example, tests are also being developed for patients who have already been taking EGFR targeted therapies but then have a recurrence. In this case, the liquid biopsy would detect new gene changes that may make the patient a good candidate for a different EGFR targeted therapy.
It is important to note that laboratory tests such as these are not required to be FDA approved to be used in a clinic or physician’s office. However, FDA approval indicates that the test has been thoroughly reviewed to be safe and provide useful treatment information.
In the future, as the technology improves and more clinical trials are done to prove that the tests work, we expect to see more liquid biopsies being used for drug selection at the time of diagnosis. For example, a doctor could give a blood test that would test for mutations in EGFR, ALK and other genes when not enough biopsy tissue is available.
With Lung Cancer Alliance’s focus on early detection of lung cancer, we are also encouraging and participating in research to develop and test these technologies as a way to detect cancer earlier, when it is more treatable.
For now, this EGFR blood-based test has been FDA approved and can be used to recommend Tarceva as a first-line therapy. In addition, many research institutions are offering additional liquid biopsy tests to patients with late-stage disease to help guide their treatment. Here are some important things to discuss with your treatment team:
- Is one of these tests a good option for me?
- What test is being used and why?
- What gene changes will the test detect?
- What do the test results mean for my treatment?
(Disclosure: Jennifer is on a clinical trial advisory panel for a company in this space and receives travel reimbursement to attend meetings. She has no role, scientific or financial, in the test referenced above.)