Cancer refers to the disease in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems. These extra cells may form a mass of tissue called a tumor. Not all tumors are cancerous; tumors can be benign or malignant.
- Benign tumors aren’t cancerous. They can often be removed, and, in most cases, they do not come back. Cells in benign tumors do not spread to other parts of the body.
- Malignant tumors are cancerous. Cells in these tumors can invade nearby tissues and spread to other parts of the body. The spread of cancer from one part of the body to another is called metastasis.
On the other hand, some cancers do not form tumors. For example, leukemia is a cancer of the bone marrow and blood.
Cancer as a general term refers to many diseases. There are more than 100 different types of cancer. Most cancers are named for the organ or type of cell in which they start – for example, cancer that begins in the breast is called breast cancer.
Cancer is the third main cause of death in Qatar. It is the reason behind approximately 12% of total deaths in the country as of early 2012.