What is an EGFR mutation and why is it important?
What is an EGFR mutation and why is it important?
Approximately 15% of European non-small cell lung cancer have a mutation in the EGFR gene. This is known as EGFR mutated or EGFR positive lung cancer. This type of lung cancer is more common in women, light or never smokers and in Asians.
EGFR stands for epidermal growth factor receptor and the EGFR protein is involved in the growth and division of healthy cells. In EGFR-positive lung cancer, there is a change (mutation or variant) in the EGFR gene causing it to remain in a “turned-on” state leading to uncontrolled cell growth and cancer.
It is important to know if your lung cancer has an EGFR mutation as it may change how your cancer is treated. Your cancer can be tested for an EGFR mutation by analysing a sample of tumour obtained from a biopsy or surgery. In some, EGFR mutation can be detected using a sample of blood, known as a liquid biopsy.
EGFR-mutated lung cancer can be treated with targeted therapies known as EGFR tyrosine kinase inhibitors that are available as tablets (pills), and they work by “turning off” the EGFR gene.
There are many different types of EGFR mutations and they are not all treated the same. The most common EGFR mutations are exon 19 deletions and exon 21 L858R mutations, representing approximately 85% of EGFR mutations. Other mutations, including EGFR exon 20 insertions, are less sensitive to EGFR TKIs and have recently had specific targeted therapies developed.
If your cancer has been removed by surgery and an EGFR mutation has been detected, your oncologist might recommend EGFR treatment for three years to reduce the risk of your cancer coming back.
If you have advanced or metastatic lung cancer with an EGFR mutation, your oncologist may recommend an EGFR treatment to shrink and control your cancer. EGFR treatments can control lung cancer for many months or years. Unfortunately, after some time lung cancer can “outsmart” the EGFR treatment and develop resistance. If that occurs your oncologist may recommend another tissue biopsy or liquid biopsy to repeat your biomarker testing to decide the next line of treatment.
If you do not know if your cancer has an EGFR mutation, then ask your doctor (oncologist) for this critical information. You can also complete this information in the profile section of the app, and we will continue to keep you informed about the latest advances that are specific to your cancer biomarker profile.
September 2022
Dr Hazel O'Sullivan received travel expenses from Takeda and an Honoraria for Amgen.