FAST FACTS
ABOUT LUNG CANCER
It was estimated that, in 2022, lung and bronchus cancer would cause approximately 1 in 4 cancer deaths in
Canada.
The more you know about lung cancer, the more prepared you’ll be to start a conversation with your doctor or with your loved one. Learning about lung cancer can help you better understand the disease, risk factors, and what you can do to help a friend or family member take control of their health. Early detection can make all the difference.
What is lung cancer?
Lung cancer is a disease that starts in the cells of the lung. Cells in the lung sometimes change and no longer grow or behave normally. A cancerous (malignant) tumour is a group of cancer cells that can grow into and destroy nearby tissue.

Adapted from the Centers for Disease Control and Prevention.
Lung cancers are divided into non-small cell lung cancer and small cell lung cancer based on the kind of cell that the cancer started in:
- Small cell lung cancer – Usually starts in the cells that line the bronchi in the centre of the lungs.
- Non–small cell lung cancer – More common than small cell lung cancer. It usually starts in glandular cells on the outer part of the lung. It may also begin in the cells that line the bronchi.
Other types of cancer can spread to the lungs from other parts of the body; this is called lung metastasis. There is also a rare type of cancer, which is not lung cancer, called pleural mesothelioma, that starts in the membrane around the lungs.