The lungs are two large spongy organs located inside the chest cavity. Air is breathed into the trachea (windpipe) and moves down two tubes called bronchi, each going to a lung. These tubes divide into bronchioles and then into tiny air sacs called alveoli. Lung cancers usually start in the cells lining the airways. There are different types of lung cancer, depending on which cells are affected.
Over 1,400 Victorians are diagnosed with lung cancer every year. Lung cancer occurs most often in adults between the ages of 40 and 70 who have smoked cigarettes for at least 20 years. We do not know the cause in all cases; however, up to nine out of 10 lung cancers are caused by smoking. Lung cancer is the most common cause of death from cancer in Australia.
Different types of lung cancer
A cancer that starts in the cells lining an organ is known as a carcinoma. There are different typesc of lung cancer, depending on which cells are affected. The two main types are:
Small cell carcinoma or ‘oat cell carcinoma’, named after its cell shape. Around 15 per cent of lung cancers are small cell carcinomas. This type of cancer spreads early and shows few early symptoms.
Non-small cell carcinoma – these cancers affect the cells that line the main bronchi.
Different types of non-small cell cancer
Some of the different types of non-small cell cancer include:
Squamous cell carcinoma is generally discovered earlier than other lung cancers and has the best outcome after treatment
Adenocarcinoma – is now the most common type in both males and females; the reason for the increasing incidence may be related to changing patterns of smoking including filtered cigarettes
Large cell carcinoma
Bronchiolo-alveolar cell carcinoma.
Sometimes it is not possible to tell which type someone has. This is because, when the cells are looked at under a microscope, they are not developed enough.
Common symptoms of lung cancer include:
Persistent cough and/or new or changed wheeze
Pains in the chest
Recurring pneumonia or chest infections
Unexplained weight loss.
Lung cancer is diagnosed using a number of tests, which may include:
Chest x-rays – cancers as small as one centimetre can be spotted on x-rays.
Sputum cytology – a sample of sputum (phlegm) is examined under a microscope to check for abnormal cells.
Bronchoscopy – a flexible tube is inserted through the mouth or nose and down the trachea, allowing the doctor to look at the lung tissue and take a small sample of tissue and phlegm.
Fine needle aspiration – a small sample of tissue is removed using a needle inserted through the chest wall.
Mediastinoscopy – a flexible tube is inserted into a cut in the neck and down to the lymph nodes to check for cancer cells in the lymph nodes.
Video-assisted thoracoscopic surgery – instruments similar to bronchoscopes are inserted into the chest wall under general anaesthetic and tissue samples may be taken.
Computed tomography (CT) scan – a specialised x-ray taken from many different angles, to build a three-dimensional picture of your body.
Fluoro-Deoxy Glucose (FDG) Positron Emission Tomography (PET) Scan – used in diagnosis and staging of lung cancer. This test involves having an injection of a small amount of radioactive material. Using the signals from this radioactive injection, a scanner can build up a picture of the body.
Other tests – including bone scans, to see if the cancer has spread to other parts of the body.
Lung cancer is categorised into stages according to its spread. This helps the doctors to decide on appropriate treatments. Treatment options include:
Surgery – to remove the affected part of the lung (lobectomy) or an entire lung (pneumonectomy). This offers the best chance of cure if the cancer has not spread beyond the lungs.
Chemotherapy – anti-cancer drugs are given to stop cancer cells from multiplying. This treatment is most effective for small cell carcinoma.
Radiotherapy – the use of x-rays to target and kill cancer cells. Radiotherapy may be used against some early stage lung cancers and to stop cancer in the lymph nodes from spreading further. Prophylactic brain radiotherapy is often offered to people with small cell lung cancer to reduce the risk of their lung cancer spreading to their brain.
Multimodality therapy – for some people, several treatments used together give the best results.
Targeted therapy – use of small molecules, often in tablet form, that may be used after chemotherapy.
Clinical trials – participation in a clinical trial that investigates the safety and effectiveness of novel drugs may be offered.
As with most cancers, the results are best if the cancer is diagnosed in its earliest stages. However, some lung cancers aren’t diagnosed until they are quite advanced. Treatment may then be limited to easing the symptoms and can include:
Radiotherapy and chemotherapy – to contain the cancer.
Medication – including pain relievers.
Surgery – to remove cancers that are blocking main airways or to seal bleeding blood vessels.
Quit smoking programs – people diagnosed with cancer have seen benefits ranging from increased longevity (length of life) and improved quality of life, depending on their disease status, once they quit smoking.