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. This information is about primary lung cancer only. When cancer starts in another part of the body and spreads to the lungs, it is named after the primary cancer (e.g. cancer that starts in the breast and spreads to the lungs is called metastatic breast cancer).

What are the different types?

There are 2 main types of primary lung cancer: non-small cell lung cancer and small cell lung cancer. 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, may also affect the lungs but are not considered lung cancer.

• non-small cell lung cancer (NSCLC) – NSCLC makes up about 85% of lung cancers. It 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.
• small cell lung cancer (SCLC) – SCLC (about 15% of lung cancers) tends to start in the middle of the lungs. This type of lung cancer usually spreads more quickly than NSCLC.

How common is lung cancer?

About 14,500 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.