What is lung cancer?

Cancer is a disease of the cells that make up the organs and tissue of the body. Lung cancer develops when cells become abnormal and grow out of control.

Over time they form a clump, also known as a tumour. Lung cancer develops in your airways - the tubes that carry air in and out of the lungs. It can grow within the lung, and it can spread outside the lung.

Prevalence of lung cancer

Lung cancer is the most common cause of cancer death in the UK, accounting for 21 per cent of all cancer deaths (2016). In 2015, there were 46,388 new cases of lung cancer in the UK (source: Cancer Research UK, accessed Jan 2019).

Thanks to earlier diagnosis and better treatments over the last decade, lung cancer mortality rates have decreased by around a tenth (9 per cent) in the UK. Rates in males have decreased by around a fifth (19 per cent), and rates in females have increased by less than a twentieth (2 per cent).

Causes of lung cancer

The principal cause of lung cancer is smoking. It is responsible for an estimated 9 out of 10 cases diagnosed. Although the more you smoke, the higher the risk of developing lung cancer, the key factor is the length of time that you have been smoking.

Other risk factors include:

  • exposure to radon gas, a natural gas with radioactive properties than can build up in homes and buildings
  • air pollution and exposure to certain chemicals in the workplace, such as asbestos, diesel exhaust and silica
  • previous smoking related cancer or a family history of lung cancer
  • low immunity caused by conditions such as HIV and Aids, or immunosuppressant drugs that are taken following an organ transplant.

Symptoms of lung cancer

There are usually no signs of the early stages of lung cancer, but as the disease progresses symptoms will develop and gradually get worse.

Some common symptoms include:

  • a persistent cough that doesn’t go away or gets worse
  • ongoing chest infections
  • a dull ache in the chest and/or a sharp pain when breathing in deeply
  • coughing up blood
  • breathlessness
  • weight loss
  • tiredness or lack of energy
  • chest or shoulder pain.

Diagnosing lung cancer

There are a number of tests used to diagnose lung cancer. These include:

Chest x-ray

A chest x-ray is used to detect lung tumours, although further tests will be required to determine an exact diagnosis.

Computed tomography (CT) scan

A CT scan is usually performed directly after a chest x-ray. A slightly radioactive dye is injected or administered orally to make the lungs show up more clearly during the scan.

PET-CT scan

A PET-CT scan is typically performed when the cancer is in its early stages. This scan helps to determine where in the lungs the active cancer cells reside.


In cases where cancer is suspected, a biopsy may be performed. This involves a sample of your cells being taken and sent to a laboratory for further analysis. There are many ways for biopsies to be taken:


A thin tube is inserted through the mouth or the nose.

Percutaneous needle biopsy

A needle is placed directly through the skin into the lungs.

Thorascopy or mediastinoscopy

Tubes with cameras are inserted into the chest through surgical incisions.

Treatment for lung cancer

The appropriate treatment of lung cancer depends on a number of factors, including:

  • the type and stage of lung cancer
  • where it is located in the lung
  • your general health.

Small cell lung cancer

This is predominantly treated by chemotherapy, although you may also have radiotherapy. Surgery is rare, since with this type of cancer, it has usually spread to the lymph glands, making most types of surgery ineffective.

Non small cell lung cancer

On the other hand, non small cell lung cancer can be treated with chemotherapy, radiotherapy or surgery – or a combination of these treatment options.