About lung cancer

What is lung cancer?

Lung cancer begins when abnormal cells grow and multiply in an uncontrolled way in the lungs. Cancer that starts in the lungs is called primary lung cancer. It can spread throughout the lungs, and to the lymph nodes, pleura, brain, adrenal glands, liver and bones. When cancer spreads to the lungs from another part of the body (e.g. breast or bowel), this is known as secondary or metastatic lung cancer. This section is about primary lung cancer only.

What are the different types?

There are 2 main types of primary lung cancer: non-small cell lung cancer and small cell lung cancer (see below). Pleural mesothelioma is a type of cancer that affects the covering of the lung (the pleura). It is different from lung cancer and is usually caused by exposure to asbestos. Other types of cancer, like cancers that start in the chest wall, and lung diseases such as silicosis may also affect the lungs and have similar symptoms but are not considered lung cancer.

Types of lung cancer

Non-small cell lung cancer (NSCLC)

NSCLCs (about 85% of lung cancers) 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.

Other, rarer types of non-small cell lung cancer are adenosquamous carcinoma, sarcomatoid carcinoma, salivary gland carcinoma and carcinoid tumours.

Small cell lung cancer (SCLC)

SCLCs (about 15% of lung cancers) tend to start in the middle of the lungs and usually spread faster than NSCLCs.

How common is lung cancer?

About 15,000 Australians are diagnosed with lung cancer each year. The average age at diagnosis is around 72 years. More men than women develop lung cancer, but since the early 1980s rates have been steadily decreasing among men and increasing among women.

The lungs

The lungs are 2 sponge-like organs that are used for breathing. They are part of the respiratory system, which also 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 sit in the chest and are protected by the rib cage.

Lobes – Each lung is made up of sections called lobes – the left lung has 2 lobes, and the right lung has 3 lobes.

Diaphragm – The lungs rest on the diaphragm, which is a wide, thin muscle that helps with breathing, and separates the chest from the abdomen (belly).

Mediastinum – The space between the lungs is called the mediastinum. A number of important 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, bean-shaped structures that collect and destroy bacteria and viruses.

Pleura – The lungs are covered by 2 thin layers of tissue called the pleura. The inner layer (visceral pleura) lines the lung surface, and the outer layer (parietal pleura) lines the chest wall, mediastinum and diaphragm. The layers are separated by a small amount of fluid that lets them smoothly slide over each other when you breathe. The pleural cavity is the potential space between the 2 layers; there is no space between the layers when the lungs are healthy.

The respiratory system

How breathing works

When you breathe in (inhale), your diaphragm moves down and air goes down the trachea and into the bronchi and bronchioles. When the inhaled air reaches the tiny air sacs called alveoli, oxygen passes through the small blood vessels (capillaries) and into the blood. When you breathe out (exhale), your diaphragm relaxes and moves back up, and a waste gas called carbon dioxide is removed from the body and released into the air.

Which health professionals will I see?

Your general practitioner (GP) will arrange the first tests to assess your symptoms. If these tests do not rule out cancer, you will usually be referred to a specialist called a respiratory physician. The specialist 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.

Health professionals you may see

• GP – assists you with treatment decisions and works in partnership with your specialists in providing ongoing care
• respiratory physician – diagnoses diseases of the lungs, including cancer, and recommends initial treatment options
• thoracic 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
• radiologist, nuclear medicine specialist – analyse x-rays and scans; an interventional radiologist may also perform a biopsy under ultrasound or CT, and deliver some treatments; a nuclear medicine specialist coordinates the delivery of nuclear scans such as PET–CT
• medical oncologist – treats cancer with drug therapies such as chemotherapy, targeted therapy and immunotherapy (also known as systemic treatments)
• cancer care coordinator or lung cancer nurse coordinator – coordinates your care, liaises with other members of the MDT; refers you to allied health professionals, provides education and information, and supports you and your family throughout treatment; care may also be coordinated by a clinical nurse consultant (CNC) or clinical nurse specialist (CNS)
• nurse – administers drugs and provides care, information and support throughout treatment
• psychologist, counsellor – help you understand and manage your emotional response to diagnosis and treatment
• dietitian – helps with nutrition concerns and recommends changes to diet during treatment and recovery
• speech pathologist – helps with communication, speech and swallowing problems from the cancer, or after treatment
• social worker – links you to support services and helps with emotional, practical and financial problems
• occupational therapist – assists in adapting your living and working environment to help you resume your usual activities
• physiotherapist, exercise physiologist – help to maintain and restore movement and mobility before and after treatment, and improve fitness and wellbeing
• palliative care specialists and nurses – work closely with the GP and cancer team to help control symptoms and maintain your quality of life and keep you comfortable and well looked after at end of life