Tumours can be benign or malignant
Benign tumours are not cancerous. They can often be removed and, in most cases, they do not come back. Cells from a benign tumour do not spread to other parts of the body. Most important, benign tumours are rarely a threat to life.
Malignant tumours are cancers. Cells in these tumours are abnormal and divide without control or order. They can invade and damage nearby tissues and organs. Cancer cells can also break away from a malignant tumour and enter the bloodstream or the lymphatic system. That is how cancer spreads from the original cancer site to form new tumours in other organs. This spread is termed metastatic disease.
Treatment of cancer depends largely on the type of cancer and the extent it has spread to other parts of the body.