If you have symptoms such as breathing difficulties and a persistent, long-term cough, your GP will carry out some routine tests to rule out possible causes other than lung cancer, such as a chest infection.
Two tests that you are likely to have are:
- a blood test
- a urine test
If you have been coughing up blood, you should be referred directly for a 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).
You will have more tests to investigate whether it is lung cancer and, if it is, how big it is and how much it has spread.
A computerised tomography (CT) scan is usually carried out after a chest X-ray.
Before having a CT scan, you will be given a drink or injected with a slightly radioactive dye. The dye makes the lungs show up more clearly on the scan. The scan is painless and takes 10–30 minutes to complete.
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.
As with a CT scan, 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 be pushed into the PET scanner. The scan is painless and takes around 30 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 take some 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 either your mouth or nose, down through your throat and into the airways of your lungs.
The procedure may be uncomfortable, but you will be given a mild sedative before to help you relax and a local anaesthetic to make your throat numb. The procedure is very quick and only takes a few minutes.
If for some reason you cannot have a bronchoscopy, you may have sputum cytology instead. This involves taking a sample of your phlegm. This will then be checked for the presence of cancer under a microscope.
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.
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.
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.
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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
The stages of non-small lung cancer are outlined below.
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 (1.1 inches)
- stage 1B – the tumour is 3–5cm (1.1–2 inches)
Stage 2 is divided into two sub-stages: 2A and 2B.
In stage 2A lung cancer:
- the tumour is 5–7cm
- the cancer 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 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
In stage 4 lung cancer, the cancer has spread to a remote part of the body, such as the bones, liver or brain.
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