Lung cancer is a malignant disease that arises in your lungs. Cancer involves the uncontrolled multiplication of abnormal cells that damage tissues and organs. Positioned in the chest behind your ribs, the lungs draw in oxygen when you inhale and expel carbon dioxide upon exhaling. Healthy lung function is crucial, yet lung cancer compromises this vital process and can lead to severe complications. In Australia, lung cancer is the leading cause of cancer-related death. It ranks fifth in overall cancer incidence, accounting for about 9% of all cases, with nearly 14,000 new diagnoses each year. The good news is that you can take steps to significantly reduce your risk of developing this disease.
Types of lung cancer
Lung cancer is divided into two main categories:
Non-small cell lung cancer (NSCLC)
This form represents 85% of cases and includes three subtypes:
- Adenocarcinoma, originates in the lung’s mucus-secreting cells
- Squamous cell carcinoma, typically begins in the larger airways of the lung
- Large cell undifferentiated carcinoma, found throughout the lung but not classified as the other subtypes
Small cell lung cancer (SCLC)
This type starts in the central regions of the lungs and generally spreads faster than NSCLC.
Signs and symptoms of lung cancer
Symptoms often appear in the later stages and may include:,
- Shortness of breath
- A new or changing cough lasting more than three weeks
- Chest or shoulder pain
- Recurring chest infections
- Hoarseness
- Difficulty swallowing
- Coughing up blood
- Clubbing (enlarged fingertips)
- Loss of appetite
- Unexplained weight loss
- Fatigue
What causes lung cancer?
Smoking is the primary risk factor: roughly 90% of male and 65% of female lung cancer cases in Australia are smoking-related. The earlier and longer you smoke, and the more cigarettes you consume, the higher your risk. Exposure to second-hand smoke can increase a non-smoker’s risk by up to 30%.
Other risk factors for lung cancer
Non-smokers can still develop lung cancer. Additional contributors include:,
- Age
- A family history of lung cancer
- Previous cancers
- Chronic lung diseases (pulmonary fibrosis, tuberculosis, COPD)
- Exposure to asbestos, radon, air pollution, or certain heavy metals
How is lung cancer diagnosed?
Confirmation may involve:,
- Medical history review and physical exam
- Chest X-ray (detects larger tumors over 1 cm)
- CT scan (identifies smaller tumors and lymph node involvement)
- PET scan (determines cancer stage)
- Blood tests
- Lung function tests
- Sputum cytology
- Lung biopsy
Following diagnosis, further testing establishes the stage and checks for metastasis, guiding the treatment plan.
How is lung cancer treated?
Treatment varies by stage and may include one or more of the following:
- Surgery
- Radiation therapy
- Thermal ablation
- Chemotherapy
- Immunotherapy
- Targeted therapy
- Palliative care
What are the stages of lung cancer?
Lung cancer is staged, meaning doctors assess how much disease is present in your body and whether it has spread.
Non-small cell lung cancer (NSCLC) is divided into six groups, designated by Roman numerals:
- Occult (hidden) stage, Malignant cells are found in sputum or other fluids but aren’t visible on imaging or other tests.
- Stage 0, Abnormal cells are limited to the top layers lining the airways without full invasion.
- Stage I, Tumor confined strictly to the lung.
- Stage II, Cancer has reached nearby lymph nodes or the pleural lining.
- Stage III, Disease involves lymph nodes between the heart and lungs or has penetrated the chest wall; it may also affect lymph nodes on the opposite side of the chest or the lower neck.
- Stage IV, Cancer has metastasized to the opposite lung, distant lymph nodes, or organs such as bones, liver, or brain.
Small cell lung cancer (SCLC) is classified into two categories:
- Limited stage, Disease is contained on one side of the chest.
- Extensive stage, Cancer has spread to the other lung or distant sites.
Can you prevent lung cancer?
You can substantially lower your risk by avoiding known risk factors such as smoking and exposure to carcinogens. If you currently smoke, quitting is the single most effective way to reduce your chance of developing lung cancer.
When should you see your doctor?
Visit your physician if you notice any signs or symptoms of lung cancer, especially if you have risk factors. If you smoke and find it hard to quit, your doctor can offer counseling, medications, and nicotine replacement therapies.
Support and more information
Lung Foundation Australia provides free support services, including social work and nursing assistance, peer support groups, pulmonary rehabilitation, multidisciplinary care, and educational webinars.