Non-Small Cell Lung Cancer and EGFR

Micrograph showing a non-small cell lung carcinoma

Non-small Cell Lung Cancer (NSCLC) is the most common type of lung cancer.

The main subtypes of NSCLC are Adenocarcinoma, Squamous Cell Carcinoma, and large Cell Carcinoma.

Adenocarcinoma lung cancer is the most common.

EGFR-positive lung cancer is a lung cancer which tests positive for an EGFR mutation. EGFR mutations are most common in people with lung adenocarcinoma.

What is EGFR?

EGFR stands for epidermal growth factor receptor. It is a protein found on the surface of cells. It helps cells to grow and divide. . In some lung cancers there is a change (called a mutation) in the EGFR gene. This change can cause cells to grow out of control and lead to cancer.

Lung cancers with one of these changes are called EGFR-positive lung cancers.

There are treatments designed to target EGFR-positive cancer cells. These are called targeted therapies.

There are different types of EGFR mutation, and this can affect which treatments are most suitable. Great progress has been made in treating EGFR lung cancer in recent years, and research continues to find new and better ways to treat the disease.

How common is an EGFR mutation?

Approximately 50,200 people are diagnosed with lung cancer each year in the UK (1). Around 12% of people with NSCLC in European and Western countries have an EGFR mutation (2). This is more common in women and people who have never smoked, but EGFR-positive lung cancer can affect anyone.

Most EGFR mutations are not inherited. They develop in the cancer cells during a person's lifetime and are generally not passed from parent to child.

How is an EGFR mutation identified?

Everyone diagnosed with certain types of non-small cell lung cancer should have their cancer tested for gene changes that could affect their treatment. This includes testing for EGFR.(3)

Knowing whether your cancer has an EGFR mutation – and which mutation it has – can help your medical team decide which treatments may work best for you.

EGFR (and other driver mutations such as ALK) can be identified in two ways.

A tissue biopsy uses a small sample of the cancer to test for EGFR and other gene changes. The sample may be taken from the lung or from another part of the body where cancer has been found. There are different ways of taking a biopsy, and your medical team will explain which is most suitable for you.
A liquid biopsy is a blood test that looks for small pieces of DNA released by cancer cells into the blood. It can sometimes find an EGFR mutation without the need for another tissue biopsy. However, not all cancers release enough DNA into the blood for the test to find it. This means that if a liquid biopsy does not find an EGFR mutation, a tissue test may still be needed.

Different types of EGFR Mutation

There are many different EGFR mutations. The two most common are called an exon 19 deletion and L858R (which is found in exon 21). Together, these make up around 85–90% of EGFR mutations. (4)

There are also less common EGFR mutations, including exon 20 insertions. Different mutations can respond differently to treatment, so it is important to know which EGFR mutation you have.

References

1. Cancer Research UK: Lung cancer incidence statistics https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/lung-cancer/incidence

2. Melosky B, Kambartel K, Häntschel M, et al. (2022). Worldwide prevalence of epidermal growth factor receptor mutations in non-small cell lung cancer: a meta-analysis. Molecular Diagnosis & Therapy, 26, 7–18. https://link.springer.com/article/10.1007/s40291-021-00563-1

3. NICE. Lung cancer: diagnosis and management (NG122). NICE lung cancer guidance

4. Passaro A, et al. (2023). Overview on Therapeutic Options in Uncommon EGFR Mutant Non-Small Cell Lung Cancer (NSCLC): New Lights for an Unmet Medical Need. International Journal of Molecular Sciences, 24, 8878. PubMed Central (PMC)