Lung cancer - Diagnosing lung cancer

You should see your GP if you have symptoms of lung cancer, such as breathlessness or a persistent cough.

Your GP will ask you about your general health and what symptoms you have been experiencing. They may examine you and ask you to breathe into a device called a spirometer, which measures how much air you breathe in and out.

You may be asked to have a blood test to rule out some of the possible causes of your symptoms, such as a chest infection.

If you have been coughing up blood or you have other persistent signs of lung cancer, you should be referred for a chest X-ray or directly to a specialist in chest conditions within two weeks.

Chest X-ray

A chest X-ray is usually the first test that is used to diagnose lung cancer. Most lung tumours show up on X-rays as a white-grey mass.

However, chest X-rays cannot give a definitive diagnosis because they often cannot distinguish between cancer and other conditions, such as a lung abscess (a collection of pus that forms in the lungs).

If your chest X-ray suggests you may have lung cancer, you should be referred to a specialist (if you've haven't already been) in chest conditions such as lung cancer. A specialist can carry out more tests to investigate whether you have lung cancer and, if you do, what type it is and how much it has spread.

CT scan

A computerised tomography (CT) scan is usually carried out after a chest X-ray. A CT scan uses X-rays and a computer to create detailed images of the inside of your body.

Before having a CT scan, you will be given an injection of a contrast medium. This is a liquid containing a dye that makes the lungs show up more clearly on the scan. The scan is painless and takes 10-30 minutes to complete.

PET-CT scan

A PET-CT scan (which stands for positron emission tomography-computerised tomography) may be carried out if the results of the CT scan show that you have cancer at an early stage.

The PET-CT scan can show where there are active cancer cells. This can help with diagnosis and treatment.

Before having a PET-CT scan, you will be injected with a slightly radioactive material. You will be asked to lie down on a table, which will slide into the PET scanner. The scan is painless and takes around 30-60 minutes to complete.  

Bronchoscopy and biopsy

If the CT scan shows that there might be cancer in the central part of your chest, you will have a bronchoscopy. A bronchoscopy is a procedure that allows a doctor or nurse to remove a small sample of cells from inside your lungs.

During a bronchoscopy, a thin tube called a bronchoscope is used to examine your lungs and take a sample of cells (biopsy). The bronchoscope is passed through your mouth or nose, down your throat and into the airways of your lungs.

The procedure may be uncomfortable, but you will be given a mild sedative beforehand to help you relax and a local anaesthetic to make your throat numb. The procedure is very quick and only takes a few minutes.

Other types of biopsy

If you're not able to have one the biopsies described above or you've had one and the results weren't clear, you may be offered a different type of biopsy. This may be a type of surgical biopsy such as a thoracoscopy or a mediastinoscopy, or a biopsy carried out using a needle inserted through your skin.

These types of biopsy are described below.

Percutaneous needle biopsy

A percutaneous needle biopsy involves removing a sample from a suspected tumour to test it at a laboratory for cancerous cells.

The doctor carrying out the biopsy will use a CT scanner to guide a needle to the site of a suspected tumour through the skin. A local anaesthetic is used to numb the surrounding skin, and the needle is passed through your skin and into your lungs. The needle will then be used to remove a sample of tissue for testing.

Thoracoscopy

A thoracoscopy is a procedure that allows the doctor to examine a particular area of your chest and take tissue and fluid samples.

You are likely to need a general anaesthetic before having a thoracoscopy. Two or three small cuts will be made in your chest to pass a tube (similar to a bronchoscope) into your chest. The doctor will use the tube to look inside your chest and take samples. The samples will then be sent away for tests.

After a thoracoscopy, you may need to stay in hospital overnight while any further fluid in your lungs is drained out.

Mediastinoscopy

A mediastinoscopy allows the doctor to examine the area between your lungs at the centre of your chest (mediastinum).

For this test, you will need to have a general anaesthetic and stay in hospital for a couple of days. The doctor will make a small cut at the bottom of your neck so that they can pass a thin tube into your chest.

The tube has a camera at the end, which enables the doctor to see inside your chest. They will also be able to take samples of your cells and lymph nodes at the same time. The lymph nodes are tested because they are usually the first place that lung cancer spreads to.

Staging

Once the above tests have been completed, it should be possible to work out what stage your cancer is, what this means for your treatment and whether it's possible to completely cure the cancer.

Non-small-cell lung cancer

Non-small-cell lung cancer (the most common type) usually spreads more slowly than small-cell lung cancer and responds differently to treatment.

The stages of non-small-cell lung cancer are outlined below.

Stage 1
The cancer is contained within the lung and has not spread to nearby lymph nodes. Stage 1 can also be divided into two sub-stages:

• stage 1A – the tumour is less than 3cm in size (1.2 inches) 
• stage 1B – the tumour is 3-5cm (1.2–2 inches)

Stage 2
Stage 2 is divided into two sub-stages: 2A and 2B.

In stage 2A lung cancer:

• the tumour is 5-7cm 
• the tumour is less than 5cm and cancerous cells have spread to nearby lymph nodes

In stage 2B lung cancer:

• the tumour is larger than 7cm 
• the tumour is 5-7cm and cancerous cells have spread to nearby lymph nodes 
• the cancer has not spread to lymph nodes but has spread to surrounding muscles or tissue 
• the cancer has spread to one of the main airways (bronchus) 
• the cancer has caused the lung to collapse 
• there are multiple small tumours in the lung

Stage 3
Stage 3 is divided into two sub-stages: 3A and 3B.

In stage 3A lung cancer, the cancer has either spread to the lymph nodes in the middle of the chest or into the surrounding tissue. This can be:

• the covering of the lung (the pleura) 
• the chest wall 
• the middle of the chest 
• other lymph nodes near the affected lung

In stage 3B lung cancer, the cancer has spread to either of the following:

• lymph nodes on either side of the chest, above the collarbones 
• another important part of the body, such as the gullet (oesophagus), windpipe (trachea), heart or into a main blood vessel

Stage 4
In stage 4 lung cancer, the cancer has either spread to both lungs or to another part of the body (such as the bones, liver or brain), or the cancer has caused fluid-containing cancer cells to build up around your heart or lungs.

Small-cell lung cancer

Small-cell lung cancer is less common than non-small-cell lung cancer. The cancerous cells responsible for the condition are smaller in size when examined under a microscope than the cells that cause non-small-cell lung cancer.

Small-cell lung cancer only has two possible stages:

• limited disease – the cancer has not spread beyond the lung 
• extensive disease – the cancer has spread beyond the lung 

Want to know more?

• Macmillan: how lung cancer is diagnosed
• Cancer Research UK: types of lung cancer