For being able to fight efficiently against cancer, I think it is useful to completely understand the definition of cancer and how cancer cells grow.
First of all, every human body is made up of trillion of cells, which continually grow and divide to form new cells. When those cells get older or become damaged, they die and consequently new cells are created to replace the old ones.
However, when cancer grows in your body, this orderly process of development of cells breaks down.
What does this mean?
So when cancer cell starts to develop, old, damaged and useless cells survive when they should die. New cells develop and grow without stopping when they are not needed. In other words, those cells do simply not recognize the signals given by the human body to stop to grow or to divide. In contrary to normal cells, cancer cells ignore a process known as „programmated cell death, which enables the body getting rid of unneeded cells.
By continuing growing and ignoring all those signal, the body has an abnormal amount of cells with no specific function. That’s why we speak of an „abnormal growth of a cell”. And it is this abnormal growth of tissue what we call „tumor”
Such a tumor can be benign or malignant.
The term „benign“ is used to describe both medical conditions and tumors are not especially dangerous. Cells in begnin tumors can not spread to other parts of the body, to other organs.
As described above, it is just an abnormal growth of human cells.
In contrary, when the tumor is malignant, the cells in those tumors (primary tumor) are out of control. These cells are able to invade nearby tissues and spread, by blood or by the lymph system, to other parts or organs of the human body. By spreading to other tissues they can continue to grow and form new tumors at this place. The formation of these new tumors are defined as „metastasis“ and can be far away from the primary tumor.