EGFR testing is used as a prognostic marker to help determine how aggressive a cancer is likely to be. It may be ordered on those diagnosed with cancer, such as non-small cell lung cancer, glioblastoma (a type of brain cancer), cancer of the head and neck, colon, breast, or pancreas.

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.

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.

EGFR blocking agents are routinely being used for treatment of colon cancer. Clinical trials are ongoing to study their use in the treatment of non small cell lung cancer, and their use may soon be considered for breast cancer treatment.

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.