What is lung cancer?

Lung cancer starts when abnormal cells grow and multiply in an uncontrolled way. Cancer that begins in the lungs is called primary lung cancer. If cancer begins in another part of the body and spreads to the lungs it is know as secondary or metastatic cancer in the lung.

Lung cancer is the leading cause of cancer death and the fifth most common cancer diagnosed excluding non-melanoma cancers. It is responsible for almost one in five cancer deaths. 

It is estimated that more than 14,700 people were diagnosed with lung cancer in 2023. The average age at diagnosis is 72 years old. 

Lung cancer is the fifth most commonly diagnosed cancer, and it is estimated that one in 20 people will be diagnosed by the time they are 85.

There are two main types of lung cancer: 

Non-small cell lung cancer (NSCLC) 

Non-small cell lung cancer is the most common type of lung cancer, accounting for around 85% of cases. There are sub-types of non-small cell lung cancer. The most common are: 

  • adenocarcinoma - begins in mucus-producing cells and makes up about 40% of lung cancers. While this type of lung cancer is most commonly diagnosed in current or former smokers, it is also the most common lung cancer in non-smokers. 
  • squamous cell (epidermoid) carcinoma - commonly develops in the larger airways of the lung. 
  • large cell undifferentiated carcinoma - can appear in any part of the lung and are not clearly squamous cell or adenocarcinoma. 

Small cell lung cancer (SCLC)  

Small cell lung cancer usually begins in the middle of the lungs and spreads more quickly than non-small cell lung cancer. It accounts for around 15% of lung cancers. 


Lung cancer signs and symptoms

Symptoms of lung cancer may include: 

  • shortness of breath

  • changes to the voice such as hoarseness

  • chest pain

  • coughing or spitting up blood

  • a new cough that does not go away

  • chest infection that lasts more than three weeks or keeps coming back

  • enlarged fingertips

  • loss of appetite

  • unexplained weight loss

  • tiredness.


Causes of lung cancer

Factors that can increase your risk of lung cancer include: 

  • smoking tobacco
  • second-hand (passive) smoking
  • exposure to asbestos
  • exposure to radon (radioactive gas)
  • exposure to occupational substances such as arsenic, cadmium, nickel, diesel fumes and soot 
  • HIV infection
  • family history
  • history of lung diseases such as lung fibrosis or emphysema
  • older age.

Diagnosis of lung cancer

You may have a number of tests to determine if you have lung cancer.

Chest x-ray

An x-ray can show larger tumours (more than 1cm wide). 

CT scan

A computerised tomography (CT) scan uses x-ray beams to take pictures inside your body and create a cross-sectional image. A CT scan is able to detect smaller tumours as well as providing information about the tumour and lymph nodes.  

PET scan

A positron emission tomography (PET) scan is used to stage lung cancer after a diagnosis. 

Lung function test

You may have a lung function test known as spirometry which checks how well your lungs are working. 

Biopsy

A small sample of tissue will be taken if a tumour is suspected after a CT scan or x-ray. There are different types of biopsy including a bronchoscopy, CT-guided core biopsy and endobronchial ultrasound. 

Sputum cytology

The sputum (mucus) from your lungs will be examined under a microscope to check for abnormal cells. 

After a diagnosis of lung cancer  

After finding out you have lung cancer you may feel shocked, upset, anxious or confused. These are normal responses. For most it will be a difficult time, however some people manage to continue with their normal daily activities. 

Talk about your treatment options with your doctor, family and friends. Seek as much information as you need. It is up to you how involved you want to be in decisions about your treatment. 




Treatment for lung cancer

 Treatment will depend on the type of lung cancer you have, how advanced it is and your general health. 

Staging

Staging is based on the TNM system and classified by the size of the primary tumour, or whether it has spread to the draining lymph nodes or more widely, particularly to the liver, bones, adrenal glands and brain. 

Surgery

if you have early stage non-small cell lung cancer you will most likely have surgery to remove the tumour. There are three main types of surgery:

  • lobectomy - a lobe is removed
  • wedge resection - part of the lobe is removed
  • pneumonectomy - a whole lung is removed.

Surgery is rarely used to treat small cell lung cancer. The main treatment for small cell lung cancer is chemotherapy. In addition, radiation therapy can be used to treat stages I-III small cell lung cancer.   

Radiation therapy (radiotherapy)

Radiation therapy(also known as radiotherapy) uses x-rays to kill or damage cancer cells and may be offered alone or in combination with surgery or chemotherapy. Radiation therapy can be used to treat locally advanced (stage III) non-small cell lung cancer. You may have radiation therapy for early stage lung cancer if surgery is not an option. Radiotherapy may also be used after surgery or as a palliative treatment. 

Thermal ablation

If surgery or radiation therapy are not suitable, you may be offered ablation treatment for localised, stage I non-small cell lung cancer. You will have needles inserted into the cancer to destroy cancer cells by heating them. 

Chemotherapy

Chemotherapy uses anti-cancer drugs to destroy cancer cells. It can be used to treat both small cell and non-small cell lung cancer. Chemotherapy may be used before surgery to shrink a tumour. It may be used before or in conjunction with radiation therapy to improve its effectiveness, before surgery to shrink the cancer, or after surgery to reduce the risk of cancer coming back. 

Immunotherapy

Immunotherapy uses specific drugs to stimulate the body's immune system and can be used to treat some forms of non-small cell lung cancer. 

Targeted therapy

Targeted therapy or personalised medicine targets specific mutations in cancer cells. Targeted therapy is generally used for advanced non-small cell lung cancer or if the cancer has returned. 

Palliative care

Palliative care seeks to improve quality of life by reducing cancer symptoms without aiming to cure the disease. Palliative treatment can be used at any stage of advanced lung cancer to assist with managing symptoms such as pain and nausea as well as slow the spread of the cancer. 

Treatment Team

Depending on your treatment, your treatment team may consist of a number of different health professionals, such as:
  • GP (General Practitioner) - looks after your general health and works with your specialists to coordinate treatment.
  • Respiratory physician- investigates symptoms, is involved in diagnosis and determines initial treatment options.
  • Thoracic (chest) surgeon- diagnoses and performs surgery for cancer and other diseases of the lungs and chest.
  • Radiation oncologist - prescribes and coordinates radiation therapy treatment.
  • Medical oncologist - prescribes and coordinates the course of chemotherapy.
  • Cancer nurse - assists with treatment and provides information and support throughout your treatment.
  • Dietitian - recommends an eating plan to follow while you are in treatment and recovery.
  • Speech pathologist- helps with swallowing and communication difficulties during and after treatment.
  • Other allied health professionals - such as social workers, pharmacists, and counsellors.

Preventing lung cancer

The most comprehensive study of cancer causation estimated that 81% of lung cancers in 2010 were caused by tobacco smoking. 

While there is no proven way to prevent lung cancer you can greatly reduce your risk by not smoking or  quitting smoking tobacco, avoiding second-hand smoke and avoiding cancer-causing agents (carcinogens) at  work.


Prognosis for lung cancer

Prognosis refers to the expected outcome of a disease. While it is not possible for a doctor to predict the exact course of the disease, they can give you an idea about the general outlook for people with the same type and stage of cancer. 

Your doctor will consider your test results, the type of lung cancer you have, the rate and extent of tumour growth, and other factors including your age, overall health and whether you are a smoker. 

The earlier the cancer is found the better the treatment outcomes will be.