Your body is made up of many different types of cells. Normally, your body tightly controls the production of new cells when they’re needed. Cancer develops when certain cells escape from your body’s control and start to change. These abnormal cells, also called cancer cells, start to increase and grow to form a lump. This is called a tumour.

If the cancer starts in your lung, it’s called primary lung cancer. If it starts in another part of your body and spreads to affect your lung, it’s called secondary lung cancer.

There are many different types of lung cancer. The two main types are:

  • non small cell lung cancer (NSCLC): This is the most common kind of lung cancer. There are three common types of non small cell lung cancer: adenocarcinoma, squamous cell carcinoma and large cell carcinoma.
  • small cell lung cancer (SCLC): This is much less common. It usually spreads more quickly and is often at an advanced stage when it’s diagnosed.


Anyone can develop lung cancer, but around 90% of cases occur in people who smoke or who used to smoke. Your risk of getting lung cancer increases with the number of cigarettes you’ve smoked and the number of years you’ve been a smoker. If you stop smoking, the risk gets lower over time – after 10 years, your risk of lung cancer falls to half that of a smoker.

Breathing in other people’s smoke over a long period can also increase your risk of getting lung cancer. Other environmental factors, such as exposure to asbestos, can increase the risk as well.

People who’ve never smoked are more likely to develop one particular type of lung cancer called adenocarcinoma.

Lung cancer usually affects people over the age of 60. Younger people can develop lung cancer, but this is rare.


You often won’t have any symptoms of lung cancer until a tumour becomes quite large. This means it might only be discovered when you have an X-ray or scan for a different reason.

As your condition progresses, you’ll begin to experience symptoms, such as:

  • a cough
  • feeling out of breath
  • chest pain
  • feeling tired
  • appetite loss
  • weight loss
  • a hoarse voice
  • blood in your mucus or phlegm

If you have these symptoms, you should see your doctor. Having these symptoms doesn’t necessarily mean you have lung cancer – they’re common and have many different causes. People with long-term lung disease might already have many of them. But it’s very important to tell your doctor if your usual symptoms change or become worse.

If you have a tumour that has spread outside your lungs, the first symptom might not come from your chest at all. In this case, symptoms might include:

  • back pain
  • bone pain or fracture
  • nerve or brain damage – this might affect walking, talking, behaviour or memory
  • confusion
  • swallowing difficulties
  • jaundice – when your skin or eyes become yellow


The doctor will ask you about your symptoms and medical history. They might also examine you. You can help by bringing a list of any medicines you’re taking.

The doctor will explain the results of any tests you’ve had, and will tell you what further tests you need. These might include:

  • a CT scan: this uses a special X-ray machine to produce a detailed image of the inside of your body
  • a biopsy: this is when a sample of tissue is taken from the tumour
  • a bronchoscopy: this is when your doctor uses a thin, flexible telescope, called a bronchoscope, to look inside your lungs. The bronchoscope is passed through your nose or mouth and down your windpipe. If the tumour is visible, your doctor can take a sample
  • an endobronchial ultrasound (EBUS): this is similar to a bronchoscopy. It uses a thin, flexible tube like a bronchoscope, which has an ultrasound scanner in the tip. This is passed into the windpipe through the mouth. It allows the doctor to scan and take tissues samples of lymph nodes in your chest
  • PET-CT scan: this is a painless procedure where you’re injected with a slightly radioactive substance which can be detected by a scanner to show if the cancer has spread to other areas of your body

These tests will help your doctor find out where the cancer is in your body and what stage it’s at – this means how big it is and how much it has spread.