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. 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.
It is essential to know the types of lung cancer, risk factors, and detection methods to get the right treatment options.
In recognition of Lung Cancer Awareness Month this November, here are 5 important things to know about primary lung cancer.
1. Who gets 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.
2. Types of lung cancer
There are 2 main types of primary lung cancer: non-small cell lung cancer and small cell lung cancer.
Non-small cell lung cancer (NSCLC)
Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, making up about 85% of lung cancer cases. The cancer cells are large and tend to grow and spread slowly. It is a less aggressive form of cancer.
There are various subtypes of NSCLC including adenocarcinoma, squamous cell carcinoma and large cell undifferentiated carcinoma, amongst other rarer types.
Small cell lung cancer (SCLC)
Small-cell lung cancer (SCLC) is a less common type of lung cancer, making up 15% of cases. SCLC tends to start in the middle of the lungs. Unlike NSCLC, its smaller, aggressive cancer cells grow and spread faster.
Other cancers and diseases affecting the lungs
Aside from these 2 primary types of lung cancer, there are other cancers affecting the lungs differently.
Pleural mesothelioma is a type of cancer that develops in the lining of the lungs, called the pleura.
Silicosis is a disease that affects the lungs and, while it has similar symptoms, it is not considered lung cancer.
3. Causes of lung cancer
There are various causes of lung cancer. The following factors are known to increase the risk of lung cancer. This does not mean you will develop lung cancer, but if you are concerned, talk to your doctor.
- Tobacco smoking - most cases of lung cancer are caused by tobacco smoking. The earlier a person starts smoking, the longer they smoke and the more they smoke, the higher their risk of developing lung cancer.
- Environmental or work-related factors - these include second-hand smoke, exposure to asbestos and other elements, and working with materials containing crystalline silica (e.g. stone, sand, rock, bricks, tiles, concrete, artificial stone) which can generate silica dust
- Personal factors - these include older age, family history, other conditions such another lung disease or human immunodeficiency virus (HIV)
4. Lung cancer tests and screening
Lung cancer can be detected through tests which will depend on a person's situation. These include initial tests, tests to confirm diagnosis, and further tests to see if the cancer has spread.
As lung cancer is typically diagnosed in the advanced stages when the cancer has already spread beyond the lungs, screening is important.
Since July 2025, free lung cancer screening has been available for eligible Australians through the National Lung Cancer Screening Program (NLCSP). This screening test can detect lung cancer earlier - even before symptoms arise - which will make treatment more likely to be effective.
5. Treatment options for lung cancer
Treatment for lung cancer will depend on the type of lung cancer you have, the stage of the cancer, how well you can breathe (your lung function) and your general health. All treatments chosen for you will be expected to be safe and effective.
Stages 1, 2 and 3 of NSCLC is usually treated with surgery, with or without chemotherapy. Chemotherapy, immunotherapy, targeted therapy and radiation therapy are usually used for stage 3 and 4 of non-small cell lung cancer, as well as small cell lung cancer.
