- About the lungs
- What is lung cancer?
- How common is it?
- Different types of lung cancer
- Information reviewed by
The lungs are the main organs in the body used for breathing and are part of the respiratory system. The respiratory system also includes the nose, mouth, windpipe (trachea) and airways to each lung. The airways to each lung are called large airways (bronchi) and small airways (bronchioles).
When you breathe in (inhale), air goes into the nose or mouth, down the trachea and into the bronchi and bronchioles. At the end of the bronchioles, tiny air sacs called alveoli pass oxygen into the blood and collect the waste gas (carbon dioxide). Carbon dioxide is released back into the atmosphere – and removed from the body – as you breathe out (exhale).
The lungs look like two large, spongy cones. Each lung is made up of sections called lobes: the left lung has two lobes and the right lung has three. The lungs rest on the diaphragm, which is a wide, thin muscle that helps with breathing.
A number of structures lie between the lungs (a space called the mediastinum), including:
- the heart and large blood vessels
- the trachea
- the tube that carries food from mouth to stomach (oesophagus)
- lymph glands (also known as lymph nodes).
The lungs are covered by a thin sheet of tissue called the pleura which is about the thickness of plastic cling wrap. Its inner layer (the visceral layer) is attached to the lungs and its outer layer (the parietal layer) lines the chest wall and diaphragm. Between the two layers is the pleural cavity which normally contains a thin film of fluid. This fluid allows the two layers of pleura to slide against each other so your lungs can move smoothly against the chest wall as you breathe.
Lung cancer is a malignant tumour in the tissue of one or both of the lungs.
Some people have primary cancer that started in the lungs. Others have cancer that started somewhere else in the body and spread to the lungs (secondary cancer or metastasis).
There are several types of lung cancer which are classified according to the type of cell affected.
Non-small cell lung cancer (NSCLC)
Makes up over 60 per cent of lung cancers. It mainly affects the cells that line the tubes into the lungs (bronchi) and smaller airways. NSCLC is classified as:
- squamous cell carcinoma
- large cell carcinoma.
Small cell lung cancer (SCLC)
Makes up about 12 per cent of lung cancers. SCLC tends to start in the middle of the lungs and it usually spreads early. Cancers are named for the way the cells appear when viewed under a microscope.
- small cell carcinoma (also known as oat cell cancer)
- mixed small cell/large cell carcinoma
- combined small cell carcinoma.
Less common lung cancers
Other less common cancers can form in the thoracic (or chest) area. These are known as thoracic cancers and include thymomas, mediastinal tumours and chest wall tumours.
A rare type of cancer that affects the covering of the lung (the pleura). It is almost always caused by exposure to asbestos. It is very different to lung cancer. For further information on pleural mesothelioma call Cancer Council 13 11 20 or select Pleural mesothelioma from the selection options under 'Please choose a type of cancer' above.
- Lung cancer is most commonly diagnosed in people aged 60 years and older.
- Having family members who have been diagnosed with lung cancer increases your risk.
- The risk of developing lung cancer is increased if you have been previously diagnosed with lung diseases such as lung fibrosis, chronic bronchitis, emphysema, and pulmonary tuberculosis.
- About one in ten smokers develop lung cancer.
- Studies from a number of countries suggest that a life-long smoker has between a 10 and 20% risk of developing lung cancer. However, compared with nonsmokers, smokers are more than ten times more likely to develop lung cancer.
- In Australia about 90% of lung cancer cases in males, and 65% in females, are estimated to be a result of tobacco smoking. The risk of lung cancer among smokers is strongly related to the length of time and the number of cigarettes a person has smoked.
Exposure to different elements
- Contact with the processing of steel, nickel, chrome or coal gas may be a risk factor. Exposure to radiation and other air pollution, such as diesel fumes, also increases the risk of lung cancer.
The symptoms of lung cancer can include:
- a new dry cough or change in a chronic cough
- chest pain or breathlessness
- repeated bouts of pneumonia or bronchitis
- coughing or spitting up blood
- unexplained weight loss
- hoarseness or wheezing
- difficulty swallowing
- abdominal and/or joint pain.
Sometimes there are no symptoms and cancer is detected during routine tests (often an x-ray). As lung cancer symptoms can be vague the disease is often discovered when it is advanced.
Having any one of these symptoms does not necessarily mean that you have cancer. Some of these symptoms may be caused by other conditions or by side effects of smoking. Talk to your doctor to have symptoms checked.
This website page was last reviewed and updated November 2016.
Information last reviewed December 2014 by: Prof Kwun Fong, Thoracic and Sleep Physician and Director, UQ Thoracic Research Center, The Prince Charles Hospital, QLD; Clare Brown, Case Manager for Thoracic Surgery, Royal Prince Alfred Hospital, NSW; Glenda Colburn, Director, Lung Cancer National Program, The Australian Lung Cancer Foundation; Prof David Ball, Chair, Lung Service, Peter MacCallum Cancer Centre; Dr Arman Hasani, Medical Oncologist, Sir Charles Gairdner Hospital, WA; Dr Paramita Dasgupta, Viertel Cancer Research Centre, Cancer Council QLD; Carmen Heathcote, Registered Nurse, Cancer Council QLD; Frances McKenzie, Cancer Connect volunteer, QLD.