Click here for links for people with cancer and their friends and families Cancer is not one disease. There about 200 different types which act very differently in the human body and respond differently to treatments. Some cancers grow rapidly and spread quickly, while others grow slowly and spread late, or not at all. We know the causes of some cancers but not of others. We can cure some cancers but not others.
Cancer is the uncontrolled growth of cells which results in damage to healthy cells.
The site where the cancer begins is called the primary tumour. Breast cancer, for example, is a primary tumour in the breast. The cancer may later spread through the lymphatic vessels or bloodstream and form secondary tumours in other places. This process of spreading is called metastasis. This is why early detection is extremely important.