HOW CANCER DEVELOPS?

Cancer develops as a result of abnormal cell reproduction. The body of an adult human being is made up of hundreds of billions of cells. Each minute, several billions of these cells die and are replaced by several billion new cells. The new cells are produced by division. In this process, a cell divides and forms two identical cells. Each of these cells then doubles in size and becomes capable of dividing. Normal cells reproduce at exactly the rate required to replace dying cells, while cancer cells still reproduce by dividing but they have lost the ability to reproduce at a controlled rate. Some tumors are non cancerous; or benign. Benign tumor does not spread to surrounding healthy tissue or other parts of the body. Malignant tumors invade, compress and eventually destroy surrounding healthy tissue.
Why is it important to detect disease early ? Cells can break away from malignant tumor. These cells are carried by the blood or lymph to other parts of the body, where they continue to multiply and form tumors. This process is called metastasis. The ability to spread makes disease extremely difficult to treat.

KINDS OF CANCER
It is classified in two ways:
(1) By cancers primary body site which mean the part of the body where the cancer first develops.
(2) Type of body tissue in which the cancer originates.

(1) Classification by body site
• Skin cancer most of skin cancers grow slowly and do not spread to other parts of the body, so these cancers are easier to treat than most other kinds. About 95% treated for skin cancer recover completely.
• Cancers of the digestive organs colon, rectum are most commonly affected organs, others are esophagus, liver, pancreas and stomach. Nearly 50% of patients that are treated for cancer of colon and rectum survive five years or longer after treatment without return of the disease.

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