Initial tests

To investigate abnormal symptoms, the first test is usually an x-ray, often followed by a CT scan. You may also have a test to check how your lungs are working and blood tests to check your overall health.

• Chest x-ray – a painless scan which can show tumours one centimetre wide or larger. 
• CT scan – uses x-ray beams to take many pictures of the inside of your body.
• Lung function test (spirometry) – measures how much air the lungs can hold and how quickly the lungs can be filled with air and then emptied.
• Blood tests – a sample of your blood will be tested to check the number of red blood cells, white blood cells and platelets (full blood count), and to see how well your kidneys and liver are working.
  
  

Biopsy

If a tumour is suspected after an x-ray or CT scan, you will need further tests to work out whether it is lung cancer. A biopsy is the usual way to confirm lung cancer. A small sample of tissue is taken from the lung and/or the nearby lymph nodes and sent to a laboratory, where a specialist doctor called a pathologist looks at the sample under a microscope. There are various ways to take a biopsy:

CT-guided lung biopsy

You will be given local anaesthetic. Using a CT scan for guidance, the doctor inserts a needle through the chest wall to remove a small piece of tumour from the outer part of the lungs. You will be observed for a few hours afterwards, as there is a small risk of damaging the lung. 

Bronchoscopy

This allows the doctor to look inside the large airways (bronchi) using a bronchoscope, a flexible tube with a light and camera. You will have sedation or a general anaesthetic, then the doctor will pass the bronchoscope into your nose or mouth, down the trachea (windpipe) and into the bronchi. If the tumour is near the bronchi, samples of cells can be collected.

Endobronchial ultrasound (EBUS)

This is a type of bronchoscopy that allows the doctor to see cancers deeper in the lung. It can also take samples of cells from a tumour or a lymph node in the middle of your chest or next to the airways, or from the outer parts of the lung.

You will have sedation or a general anaesthetic, and the doctor will put a bronchoscope with a small ultrasound probe on the end into your mouth. The ultrasound probe uses soundwaves to create pictures that show the size and position of the tumour and allows the doctor to measure it and take samples.

Mediastinoscopy

This is not used as often as other biopsy methods but is sometimes used if a sample is needed from the lymph nodes found between the lungs (mediastinum). You will have a general anaesthetic, then a small cut (incision) will be made in the front of your neck and a thin tube passed down the outside of the trachea.

Thoracoscopy

If other tests are unable to provide a diagnosis, you may have a thoracoscopy. This uses a thoracoscope, a tube with a light and camera, to take a tissue sample from the lungs. It is usually done under general anaesthetic with a type of keyhole surgery called video-assisted thoracoscopic surgery (VATS). 

Biopsy of neck lymph nodes

A sample of cells may be taken from the lymph nodes in the neck with a thin needle. This is done using ultrasound for guidance.

Molecular testing

The biopsy sample may be tested for genetic changes or specific proteins in the cancer cells (biomarkers). The tests are known as molecular tests and help work out which drugs may be most effective in treating the cancer.

Genetic changes

Genes are found in every cell of the body and are inherited from both parents. If something triggers the genes to change (mutate), cancer may start growing. A mutation that occurs after you are born is not the same thing as genes inherited from your parents.

The most common genetic mutations seen in non-small cell lung cancer are changes in the EGFR (epidermal growth factor receptor), ALK (anaplastic lymphoma kinase) and ROS1 genes. Some mutations can be treated with medicines known as targeted therapy, but others do not yet have a targeted therapy available.

Proteins

Certain proteins found in some types of non-small cell lung cancer suggest that the cancer may respond to immunotherapy. The most common protein tested for is called PD-L1.

Further tests

If the tests described above show that you have lung cancer, you will have further tests to see whether the cancer has spread to other parts of your body.

A PT-CT scan combines a PET (positron emission tomography) scan with a CT scan in one machine and can provide detailed information about the cancer. A small amount of radioactive glucose solution is injected into a vein, which helps cancer cells show up more brightly on the scan. Sometimes a PET–CT scan is done to work out if a biopsy is needed or to help guide the biopsy procedure. 

You may also have a CT or MRI (magnetic resonance imaging) scan of the brain. If a PET–CT scan is not available or results are unclear, you may have a CT scan of the abdomen or a bone scan.

Staging lung cancer

The tests described above help your specialist work out how far the cancer has spread. This is known as staging, and it helps your health care team recommend the best treatment for you.

Non-small cell lung cancer (NSCLC) is staged using the TNM (Tumour-Nodes-Metastasis) system. Although the TNM system can be used for SCLC, doctors usually use a two-stage system:

• Limited stage – cancer is only on one side of the chest and in one part of the lung, nearby lymph nodes may also be affected. 
• Extensive stage – cancer has spread widely through the lung, to the other lung, to lymph nodes on the other side of the chest or to other areas of the body.

Prognosis

Prognosis means the expected outcome of a disease. It is not possible for anyone to predict the exact course of the disease. Instead, your doctor can give you an idea about the general outlook for people with the same type and stage of cancer.

To work out your prognosis, your doctor will consider:

• your test results
• the type and stage of lung cancer
• the rate and extent of tumour growth
• how well you and the cancer respond to treatment
• other factors such as your age, fitness and overall health,
• whether you're currently a smoker.

Discussing your prognosis and thinking about the future can be challenging and stressful. It is important to know that although the statistics for lung cancer can be frightening, they are an average and may not apply to your situation.

As in most types of cancer, the results of lung cancer treatment tend to be better when the cancer is found and treated early. Newer treatments such as targeted therapy and immunotherapy are effective in some people with advanced lung cancer and are bringing hope to those who have lung cancer that has spread.