Your body constantly produces new cells. Normal cells follow a typical cycle: They grow, divide and die. Cancer cells, on the other hand, don't follow this cycle. Instead of dying, they multiply and continue to reproduce other abnormal cells. So, as a tumour gets bigger, cancer cells can spread to surrounding tissues and structures by pushing on normal tissue beside the tumour. Cancer cells also make enzymes that break down normal cells and tissues as they grow. Cancer that grows into nearby tissue is called local invasion or invasive cancer.
