Cancer is a term used for diseases 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.
Cancer is not just one disease but 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 colon is called colon cancer; cancer that begins in basal cells of the skin is called basal cell carcinoma.
Cancer types can be grouped into broader categories. The main categories of cancer include:
- Carcinoma – cancer that begins in the skin or in tissues that line or cover internal organs.
- Sarcoma – cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
- Leukemia – cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood.
- Lymphoma and myeloma – cancers that begin in the cells of the immune system.
- Central nervous system cancers – cancers that begin in the tissues of the brain and spinal cord.
- Origins of Cancer
- All cancers begin in cells, the body’s basic unit of life. To understand cancer, it’s helpful to know what happens when normal cells become cancer cells.
- The body is made up of many types of cells. These cells grow and divide in a controlled way to produce more cells as they are needed to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells.
- However, sometimes this orderly process goes wrong. The genetic material (DNA) of a cell can become damaged or changed, producing mutations that affect normal cell growth and division. When this happens, cells do not die when they should and new cells form when the body does not need them. The extra cells may form a mass of tissue called a tumor.
- 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.
A report from the nation’s leading cancer organizations shows that rates of death in the United States from all cancers for men and women continued to fall between 2003 and 2007, the most recent reporting period available. (Read more about the Annual Report.)
Estimated new cases and deaths from cancer in the United States in 2011:
- New cases: 1,596,670 (does not include nonmelanoma skin cancers)
- Deaths: 571,950
- Cancers that are diagnosed with the greatest frequency in the United States are listed below. (Read more about Common Cancer Types.)
|Bladder Cancer||Lung Cancer|
|Colon and Rectal Cancer||Non-Hodgkin Lymphoma|
|Endometrial Cancer||Pancreatic Cancer|
|Kidney (Renal Cell) Cancer||Prostate Cancer|
The risk of developing many types of cancer can be reduced by practicing healthy lifestyle habits, such as eating a healthy diet, getting regular exercise, and not smoking. Also, the sooner a cancer is found and treatment begins, the better the chances are that the treatment will be successful.