What is cancer?

What is cancer?

Cancer isn’t one disease – it’s more than 100. But all cancers have something in common. This video explains what that is.

What is cancer? 
Voice-over: What is cancer?  

Did you know that cancer isn't one disease, it's more than 100? But all cancers have something in common, and this video explains what it is.  

Cancer is a disease that starts in our cells. Our bodies are made up of trillions of cells, grouped together to form tissues and organs such as muscles and bones, the lungs and the liver.  

Genes inside each cell tell it to grow, work, divide and die. Normally, our cells follow these orders and we remain healthy. But sometimes the instructions in some cells get mixed up and these cells start to grow and divide uncontrollably.  

Over time, the abnormal cells may form a lump, or tumour. Some tumours are noncancerous and some are cancerous. Cells that aren't cancerous stay in one place in the body and are not usually life-threatening.

Cells that are cancerous however, can grow into nearby tissues and spread to other parts of the body. Cancer cells that spread to other parts of the body are called metastases.  

The first sign that cancer has spread, or metastasized, is often swelling of nearby lymph nodes, like those in the neck, underarm or groin areas. But cancer can spread almost anywhere in the body.  

Cancers are named after the part of the body where they start. For example, cancer that starts in the bladder but spreads to the lung is called bladder cancer with lung metastases.  

To find out more about cancer, visit the Canadian Cancer Society online at cancer.ca or call 1-888-939-3333.