Tests for lung cancer

You usually have several tests to check for lung cancer. This might include all or some of the following:

• a chest x-ray

• CT or MRI scans

• a bronchoscopy

• ultrasound scans

• biopsies

Tests your GP might do

Most people start by seeing their GP. They can do some tests to help them decide whether you need a referral to a specialist. Your GP might send you for a chest x-ray.

Chest x-ray

A chest x-ray is a test that can help to diagnose lung cancer.

X-rays use high energy rays to take pictures of the inside of your body. They can show up changes in the lungs. Changes can be due to cancer but can also be caused by other lung conditions.

If you have symptoms that could be caused by lung cancer, your doctor will arrange for you to have an x-ray.

Tests your specialist might do

Depending on the results of your tests, your GP might refer you to a specialist. In some hospitals, you might see a doctor specialising in breathing problems (respiratory physician) first. They usually do all the necessary tests until you have a diagnosis. If it is lung cancer, and it can’t be removed with surgery, they will refer you to a medical oncologist for lung cancer. This is a doctor who specialises in lung cancer.

The tests the specialists might do include: 

• CT scan with contrast

• PET-CT scan

• bronchoscopy

• needle biopsy through the skin

• surgical biopsy

• neck lymph node ultrasound and biopsy

• endobronchial ultrasound (EBUS-TBNA)

• endoscopic ultrasound

• mediastinoscopy

• testing for gene mutations in lung cancer

• bone scan

• ultrasound

• MRI

CT scan with contrast

A CT scan is a test that uses x-rays and a computer to create detailed pictures of the inside of your body. It takes pictures from different angles. The computer puts them together to make a 3 dimensional (3D) image. CT (or CAT) stands for computed (axial) tomography.

Doctors can use a CT scan to look for lung cancer. It can help them to:

• diagnose and stage lung cancer
• check whether cancer has spread to the liver, adrenal glands, lower part of the neck or lymph nodes in the chest

PET-CT scan

A PET-CT scan combines a CT scan and a PET scan. PET stands for positron emission tomography. The PET scan uses a mildly radioactive drug to show up areas of your body where cells are more active than normal.

The CT scan takes a series of x-rays from all around your body and puts them together to create a 3 dimensional (3D) picture.

A PET-CT scan for lung cancer can help to show:

• exactly where the cancer is in your lung 
• whether it has spread elsewhere in the body and to lymph nodes in the chest
• how aggressive (metabolic active) is the cancer
• decide which is the best treatment for your cancer
• check whether your cancer has come back 
• plan radiotherapy treatment
• how well a cancer treatment is working

Bronchoscopy

A bronchoscopy is a test to look at the inside of the breathing tubes (airways) in your lungs.

You might have this test to allow your doctor to:

• look for the cause of your symptoms
• help your doctor see any areas that look abnormal on an x-ray or scans
• take samples of cells

These samples might be a tissue sample called a biopsy. Or your doctor might take some cells with a small brush or a liquid to collect them.

Needle biopsy through the skin

This test is called a percutaneous lung biopsy. Your doctor takes a sample of lung tissue by passing a needle into the lung.

You might have this test if your doctor has seen an abnormal looking area in your lung or airways using a CT scan.

Surgical biopsy

A surgical biopsy of the lung can help diagnose lung cancer. The surgeon carries out your biopsy in one of the following ways:

• keyhole surgery, also called video assisted thoracoscopic surgery (VATS)
• open surgery, through a small cut in the chest wall (small thoracotomy)

You might have this test if:

• a CT scan has shown an abnormal area in your lung or airways
• the area is difficult to sample, because of its position

Neck lymph node ultrasound and biopsy

Ultrasound scans use high frequency sound waves to create a picture of a part of the body. The ultrasound scanner has a microphone that gives off sound waves. The sound waves bounce off the structures inside your body, and the microphone picks them up. The microphone links to a computer that turns the sound waves into a picture.

You might have this test if your doctor has seen changes in the lymph nodes in your neck on a CT scan. It can find out if there are cancer cells in the lymph glands.

Your doctor uses an ultrasound scanner to help them take a small amount of lymph node tissue using a fine needle.

Endobronchial ultrasound (EBUS-TBNA)

Endobronchial ultrasound for lung cancer is also called Endobronchial Ultrasound-guided Transbronchial Needle Aspiration (EBUS-TBNA). This test uses a narrow flexible tube to look at the inside of the breathing tubes (airways) in your lungs. The tube has an ultrasound probe. It uses high frequency sound waves to create pictures of the lungs and structures outside the airway walls, such as the lymph nodes.

Your doctor can see any areas that look abnormal and take samples (biopsies) to test.

This test can show if an abnormal looking area is lung cancer and the size of the tumour. It can also show if the cancer has spread into other lung areas or outside the lung.

Endoscopic ultrasound

This test combines ultrasound and endoscopy to look at the areas around your food pipe. The main airway (wind pipe) is close to the food pipe.

To do the test your doctor uses a long flexible tube called an endoscope. It has a tiny camera and light on the end and an ultrasound probe attached. The ultrasound scan uses high frequency sound waves to create a picture of the inside of your body.

An endoscopic ultrasound can check whether lung cancer has spread into the lymph nodes in the centre of the chest close to the windpipe.

Mediastinoscopy

Mediastinoscopy is a test where your doctor makes a small cut at the lower part of your neck. They then put a long, thin, flexible tube called a mediastinoscope through the cut and into the mediastinum. The mediastinum is the centre of your chest and area between your lungs. It contains:

• the heart
• the main blood vessels
• lymph nodes (glands)
• the food pipe (oesophagus)

A camera at the end of the tube connects to a large screen so the doctor can see pictures of the inside of your chest. They can examine the area between your lungs and take tissue samples (biopsies) if needed.

You might have this test to see if cancer cells have spread into the lymph nodes around the windpipe.

Testing for gene mutations in lung cancer

Some lung cancers, such as non small cell lung cancer have changes in particular genes and proteins. These changes can be used as targets for specific drug treatments.

Genes are found on chromosomes within all cells. They tell the cell which proteins to make.

Scientists can look at lung cancer samples in the laboratory and search for gene changes (mutations) that change how the cancer grows.

Doctors use this information to plan the best treatment based on the genetic type of the cancer. This is called targeted cancer treatment or personalised therapy.

Gene changes in lung cancer

Some non small cell lung cancers have changes in genes that make the cancer grow and divide, such as the:

• epidermal growth factor receptor (EGFR) gene
• anaplastic lymphoma kinase (ALK) gene
• ROS1 gene
• BRAF gene
• neurotrophic tyrosine receptor kinase (NTRK) gene
• mesenchymal-epithelial transition (MET) gene
• RET gene
• KRAS gene

Non small cell lung cancer cells can also have a higher than normal amount of PD-L1 proteins. PD-L1 proteins are also found on normal cells.

Your doctor might test for changes in one or more of these genes before you start treatment.

To have these tests, your cancer must be a non small cell lung cancer that has spread into the area around the lung or elsewhere in the body (an advanced cancer). Or you might have this test as part of a clinical trial.

The genetic mutation test

Doctors look for gene mutations in a tissue sample, usually taken during a needle biopsy. They test a sample they already have from your original cancer tests. Or they might use a biopsy from your operation if you had one. The testing is done in the laboratory. 

Another test that looks for gene changes in cells is the FISH test. FISH stands for fluorescence in situ hybridisation.

Research has found that some targeted cancer drugs work well for some people with certain gene mutations in non small cell lung cancer. These drugs change the way that cells work, and they help the body control the growth of cancer.

Bone scan

A bone scan is less often used nowadays to check for changes in your bones. You might instead have a PET or CT scan.

A bone scan can show changes or abnormalities in the bones. It is also called:

• a radionuclide scan
• bone scintigraphy
• nuclear medicine bone scan

A bone scan can look at a particular joint or bone. In cancer it is more usual to scan the whole body.

A large camera (called a gamma camera) scans you and picks up radioactivity.

If there are changes on the scan, they may be called hot spots. These are not always cancer. Bone changes can happen for other reasons, like arthritis. You might need a CT scan to know exactly where these abnormal areas are.

Your specialist might ask you to have a bone scan to help work out whether your lung cancer has spread.

Ultrasound

You might have an ultrasound scan to look at organs in the abdomen, such as your adrenal glands or liver.

The ultrasound scanner has a microphone that gives off sound waves. The sound waves bounce off the organs inside your body, and the microphone picks them up. The microphone links to a computer that turns the sound waves into a picture on the screen.

Your specialist might ask you to have an ultrasound scan to see if your lung cancer has spread.

MRI

An MRI is a scan that creates pictures using magnetism and radio waves. MRI scans produce pictures from angles all around the body and clearly show soft tissues. MRI stands for magnetic resonance imaging.

Doctors use an MRI scan to check whether:

• lung cancer has spread to the brain
• Pancoast tumours (superior sulcus tumours), a very rare type of lung cancer, have spread to a big nerve that goes into the arm (the brachial plexus), blood vessels or the spine