Cancer is a disease of the cells, which are the body’s basic building blocks. Cancer occurs when abnormal cells grow in an uncontrolled way. These abnormal cells can damage or invade the surrounding tissues, or spread to other parts of the body, causing further damage. Tumours can be benign (not cancer) or malignant (cancer).
Benign tumours (not cancer): Benign tumours do not spread outside their normal boundary to other parts of the body. Some benign tumours are precancerous and may progress to cancer if left untreated. Other benign tumours do not develop into cancer.
Malignant tumours (cancer): A malignant tumour is made up of cancer cells. When it first develops, this malignant tumour may be confined to its original site. eg. in the liver. If these cells are not treated, they may spread into surrounding tissues, becoming invasive cancer.