Lung cancer


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What is lung cancer?The lungs | Types of lung cancer | Risk factors | How common is lung cancer? | Symptoms | Health professionals 

What is lung cancer?

Lung cancer begins when abnormal cells grow and multiply in an uncontrolled way in one or both lungs. Cancer that starts in the lungs is known as primary lung cancer. It can spread to other parts of the body such as the lymph nodes, brain, adrenal glands, liver and bones.

When cancer starts in another part of the body and spreads to the lungs, it is called secondary or metastatic cancer in the lung. This information is about primary lung cancer only.

Cancer care pathways

For an overview of what to expect during all stages of your cancer care, from diagnosis to treatment and beyond, read or download the Guide to Best Cancer Care  for lung cancer. This resource is also available in Arabic, Chinese, Greek, Hindi, Italian, Tagalog and Vietnamese – see details on the site.

The lungs

The lungs are the main organs for breathing and are part of the respiratory system. As well as the lungs, the respiratory system includes the nose, mouth, trachea (windpipe), and airways (tubes) to each lung. There are large airways known as bronchi (singular: bronchus) and small airways called bronchioles.


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.


The space between the two lungs is called the mediastinum. Several structures lie in this space, including:

  • the heart and large blood vessels
  • the trachea – the tube that carries air into the lungs
  • the oesophagus – the tube that carries food to the stomach
  • lymph nodes – small structures that collect and destroy bacteria and viruses.


The lungs are covered by two layers of a thin sheet of tissue called the pleura, which is about as thick as plastic cling wrap. The inner layer (the visceral layer) lines the lung surface, and the outer layer (the parietal layer) lines the chest wall and diaphragm. The layers are separated by a film of fluid that lets them slide over each other. This helps the lungs move smoothly against the chest wall when you breathe. The pleural cavity is the potential space between the two layers, but there is no space between them when the lungs are healthy.


Respiratory system

How breathing works

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). When you breathe out (exhale), carbon dioxide is removed from the body and released back into the atmosphere.

What are the different types?

There are two main types of primary lung cancer. These are classified according to the type of cells affected.

Non-small cell lung cancer (NSCLC)

NSCLC makes up about 85% of lung cancers. It may be classified as:

  • adenocarcinoma - begins in mucus-producing cells; more often found in outer part of the lungs
  • squamous cell carcinoma – begins in thin, flat cells; most often found in larger airways
  • large cell undifferentiated carcinoma - the cancer cells are not clearly squamous or adenocarcinoma

Small cell lung cancer (SCLC)

SCLC makes up about 15% of lung cancers. It tends to start in the middle of the lungs, and usually spreads more quickly than NSCLC.


Other types of cancer can also affect the lung area but are not considered lung cancer. These include tumours that start in the space between the lungs (mediastinum) or in the chest wall. Pleural mesothelioma is a cancer that affects the covering of the lung (the pleura). It is different to lung cancer and is usually caused by exposure to asbestos. See Understanding Mesothelioma.

What are the risk factors?

The causes of lung cancer are not fully understood, and some people develop lung cancer without having any known risk factors. The factors listed below are known to increase the risk of developing the disease. Having these risk factors does not mean you will develop lung cancer, but if you are concerned about your risk, talk to your doctor.

Tobacco smoking

In Australia, about 90% of lung cancer cases in males and 65% in females are estimated to be a result of tobacco smoking. The earlier a person starts smoking, the longer they smoke and the more cigarettes they smoke, the higher the risk of developing lung cancer. However, about one in five people (21%) who are diagnosed with lung cancer have never been smokers.2

Second-hand smoking

Breathing in other people's tobacco smoke (passive or second-hand smoke) can cause lung cancer. Living with a smoker increases a non-smoker's risk by up to 30%.3

Exposure to asbestos

People who are exposed to asbestos are more likely to develop lung cancer or pleural mesothelioma. Although the use of asbestos in building materials has been banned across Australia since 2004, there is still asbestos in some older buildings and fences.

Exposure to other elements

People exposed to radioactive gas (radon) in the workplace, such as uranium miners, have an increased risk of lung cancer. Air pollution is another risk factor. Contact with the processing of arsenic, cadmium, steel and nickel, and exposure to diesel in the workplace, may also be risk factors.

Family history

You may be at a higher risk if a family member has been diagnosed with lung cancer.

Personal history

Having another lung disease (e.g. lung fibrosis, chronic bronchitis, pulmonary tuberculosis, emphysema) or HIV may increase the risk of lung tumours.

Older age

Lung cancer is most commonly diagnosed over the age of 60 years, though it can occur in younger people.

How common is lung cancer?

Each year, about 12,200 Australians are diagnosed with lung cancer.  The average age at diagnosis is 72. It is the fifth most common cancer in Australia and accounts for 9% of all cancers diagnosed.4 More men than women develop lung cancer. 

What are the symptoms?

The main symptoms of lung cancer are:

  • a persistent new cough lasting more than three weeks or a change in a cough you've had for a long time
  • breathlessness
  • chest and/or shoulder pain
  • a chest infection that lasts more than three weeks or that keeps coming back. 
  • coughing or spitting up blood.

A person diagnosed with lung cancer may also have experienced symptoms such as fatigue, weight loss, hoarse voice, wheezing, difficulty swallowing, abdominal or joint pain, and enlarged fingertips (finger clubbing). Having any one of these symptoms does not necessarily mean that you have lung cancer. Some of these symptoms may be caused by other conditions or from the side effects of smoking. However, if you have symptoms, see your doctor without delay.

Lung cancer symptoms can be vague and the disease is often discovered when it has spread to other parts of the body. Sometimes, there are no symptoms and the cancer is found during routine tests (often an x-ray or CT scan) for other conditions.

Which health professionals will I see?

Your general practitioner (GP) will organise the first tests to assess your symptoms. If these tests do not rule out cancer, you will usually be referred to a respiratory physician, who will arrange further tests. If lung cancer is diagnosed, the specialist will consider treatment options. Often these will be discussed with other health professionals at what is known as a multidisciplinary team (MDT) meeting. During and after treatment, you will see a range of health professionals who specialise in different aspects of your care. The health professionals you see will depend on whether the lung cancer has spread.

Health professional



assists you with treatment decisions and works in partnership with your specialists in providing ongoing care

respiratory (thoracic) physician*

diagnoses diseases of the lungs, including cancer, and recommends initial treatment options

thoracic (chest) surgeon*

diagnoses and performs surgery for cancer and other diseases of the lungs and chest (thorax)

radiation oncologist*

treats cancer by prescribing and overseeing a course of radiation therapy

radiation therapist

plans and delivers radiation therapy

medical oncologist*

treats cancer with drug therapies such as chemotherapy, targeted therapy and immunotherapy (systemic treatment)

cancer care coordinator or lung cancer nurse

coordinates care, liaises with MDT and supports you and your family throughout treatment; care may also be coordinated by a clinical nurse consultant (CNC) or clinical nurse specialist (CNS)


administers chemotherapy and other drugs and provides care, information and support throughout treatment


recommends an eating plan to follow while you are in treatment and recovery

speech pathologist

helps with communication and swallowing after treatment

social worker

links you to support services and helps with emotional, practical or financial problems

physiotherapist, occupational therapist

assist with physical and practical issues, including restoring movement and mobility after treatment and recommending aids and equipment

counsellor, psychologist

help you manage your emotional response to diagnosis and treatment

palliative care specialist* and nurses

work closely with the GP and cancer specialists to help control symptoms and maintain your quality of life

*Specialist doctor

Expert content reviewers:

A/Prof Nick Pavlakis, President, Australasian Lung Cancer Trials Group, President, Clinical Oncology Society of Australia, and Senior Staff Specialist, Department of Medical Oncology, Royal North Shore Hospital, NSW; Dr Naveed Alam, Thoracic Surgeon, St Vincent’s Private Hospital Melbourne, VIC; Prof Kwun Fong, Thoracic and Sleep Physician and Director, UQ Thoracic Research Centre, The Prince Charles Hospital, and Professor of Medicine, The University of Queensland, QLD; Renae Grundy, Clinical Nurse Consultant – Lung, Royal Hobart Hospital, TAS; A/Prof Brian Le, Director, Palliative Care, Victorian Comprehensive Cancer Centre – Peter MacCallum Cancer Centre and The Royal Melbourne Hospital, and The University Of Melbourne, VIC; A/Prof Margot Lehman, Senior Radiation Oncologist and Director, Radiation Oncology, Princess Alexandra Hospital, QLD; Susana Lloyd, Consumer; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA; Nicole Parkinson, Lung Cancer Support Nurse, Lung Foundation Australia.


2. Cancer Australia, Risk factors for lung cancer: an overview of the evidence, Cancer Australia, Surry Hills, NSW, 2014.

3. IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, Personal Habits and Indoor Combustions, International Agency for Research on Cancer, Lyon, France, 2012. (IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, vol. 100E.)

4. Australian Institute of Health and Welfare (AIHW), Cancer in Australia 2017, AIHW, Canberra, 2017.

Page last updated:

The information on this webpage was adapted from Understanding Lung Cancer - A guide for people with cancer, their families and friends (October 2020). This webpage was last updated in March 2021. 

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