• When you breathe in, air passes from your nose or mouth through the windpipe (trachea), dividing into two tubes (airways), going to each lung (bronchus).

• The right and left bronchus then divide to form smaller tubes called bronchioles, which carry air through the lungs.

• The right lung has three main areas (known as lobes) and the left lung has two.

Remember: Lung cancer is not infectious and cannot be passed on to other people. The biggest cause of lung cancer is smoking.

Types of lung cancer

The most common type of lung cancer is primary lung cancer (cancer that starts in the lungs, rather than cancer that started somewhere else and spread to the lungs).

There are two main types of primary lung cancer:

• Small cell lung cancer

• Non-small cell lung cancer

What causes lung cancer?

• Smoking: People who started smoking early, or smoke a lot, have a higher risk of developing lung cancer.

• Genetics: There is some genetic risk for smokers that could make them even more likely to develop lung cancer.

• Age: It’s rare for a person to be diagnosed with lung cancer before the age of 40. Most lung cancer patients are over 60.

• Asbestos: Asbestos exposure can lead to lung cancer. Normally it develops into mesothelioma.

What are the symptoms?

The symptoms of lung cancer may include any of the following:

• a continuing cough, or change in a long-standing cough

• a chest infection that does not get better

• increasing breathlessness

• coughing up blood-stained phlegm (sputum)

• a hoarse voice

• a dull ache, or a sharp pain, when you cough or take a deep breath

• loss of appetite and loss of weight

• difficulty swallowing

•  excessive tiredness (fatigue) and lethargy

If you have any of these symptoms you should have them checked by your doctor, but remember, they are common to many illnesses other than lung cancer.

How is it diagnosed?

After visiting a GP a referral will probably be made to a hospital for some tests. These may include:

• Chest X-rays

• Blood tests

• MRI scan - uses magnetic fields to build up a series of cross-sectional pictures of the body.

• Mediastinoscopy - a procedure done under a general anaesthetic, where the doctor can look inside the chest at the area behind the breast bone.

• Lung biopsy - some cells are removed from the abnormal area and examined under a microscope.

• PET scan - a scan that shows how tissues inside the body are working.

• Ultrasound scan - uses sound waves to look at internal organs.

• Lung function tests - breathing tests to check how well the lungs are working.

• Sputum test - taking a sample of the sputum (spit) and looking at it under a microscope to see if there are cancer cells present.

If the results of the test show the presence of lung cancer, another referral will be made to a doctor who specialises in the treatment of lungs (called an Pulmonary doctor).

Staging

The stage of a cancer describes its size and whether it has spread. Once the doctors know the stage of the cancer, they can decide on the most appropriate treatment.

Generally cancer is divided into four stages:

• Stage 1: is small and localised.

• Stages 2 or 3: it has spread into surrounding structures.

• Stage 4: it has spread to other parts of the body.

How is it treated?

Treatment depends on the size and type of the tumour and its location. There can be side effects associated with treatment.

Treatment for small cell lung cancer

Chemotherapy is the main treatment for small cell lung cancer. Radiotherapy is sometimes given as well. Surgery is not a common form of treatment because small cell lung cancer has often spread to other parts of the body.

If surgery is an option, then chemotherapy and/or radiotherapy may be given after surgery. This is called adjuvant treatment.

Non-small cell lung cancer

Treatment for non-small cell lung cancer depends on the stage of the cancer. Surgery is usually the first step in treatment for stage 1 cancer, and is less used as the stages increase because this usually means the cancer has spread. Surgery is often given with chemotherapy and radiotherapy.

Radiotherapy is usually given first if surgery is not an option, with chemotherapy often used to kill any remaining cancer cells.

Remember that the treatment plan for each person can be quite different depending on the cancer stage.