How is it used?
EGFR testing may be ordered on those diagnosed with cancer, such as
colon cancer, non-small cell lung cancer, glioblastoma (a type of brain cancer), and cancer of the head and neck, breast, or pancreas. It is primarily used to help guide treatment of some cancers and to determine whether a patient can benefit from targeted therapy with an antibody to EGFR. Several drugs called “EGFR inhibitors” have been developed to target the action of EGFR. If a person’s tumor has increased amounts of EGFR, then an EGFR inhibitor may be considered as part of the cancer treatment.
The test may also be used as a prognostic marker to help determine how aggressive a cancer is likely to be.
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When is it ordered?
EGFR testing may be ordered as part of an initial workup of particular cancers or performed on those with certain cancers that are not responding to chemotherapy. It may be done at any time, but it requires a sample of the tumor tissue. If a sample is available from a previous
biopsy, it can be done on that sample.
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What does the test result mean?
EGFR testing is not diagnostic, but it helps the doctor understand more about the tumor’s characteristics, evaluate a patient’s overall prognosis, and determine treatment options. If testing using either of the methods is positive, then the patient is more likely to have a tumor that is aggressive and resistant to chemotherapy.
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Is there anything else I should know?
EGFR blocking agents are routinely being used for treatment of
colon cancer and are used with some head and neck cancers. Clinical trials are ongoing to study their effectiveness in the treatment of non small cell lung cancer, and their use may soon be considered for
breast cancer treatment.
The utility of these EGFR inhibitors and their correlation to EGFR results in different types of cancers has yet to be fully established. The role of testing for certain EGFR gene mutations and the mutations’ affect on a patient’s responsiveness to treatment is also being explored.
EGFR testing is not available in every laboratory. If your doctor sends your sample to a reference laboratory, the results may take a few weeks to return.
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