What is cancer?

Cancer is a disease that develops when abnormal cells in your body divide and multiply without control. Normally, cells grow and divide to produce more cells only when your body needs them. But sometimes, cells keep dividing when new cells are not needed. These extra cells may form a mass called a tumor. Tumors can be either benign, which means not cancerous, or malignant, which is cancerous.

Cancer cells can develop anywhere in the body and can spread to other body parts through your blood and lymph systems. Lymph is a clear fluid that carries blood cells that fight infection and disease throughout the body. Lymph travels through a system of vessels, much like blood vessels.

Cancer cells damage the organs and tissues they invade, causing a variety of symptoms. There are different types of cancer and symptoms can vary greatly depending on the location, or the organs and tissue that are affected.

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