Cancer is the name used for a large and diverse group of diseases that involve cells in which the control mechanism has failed or does not exist, allowing the cells to divide and multiply uncontrollably. Healthy cells grow and divide in a regulated manner so that old or damaged cells can be replaced with new, healthy cells as a normal way to keep the body in good health. Cancer cells have mutated so that the old cells do not die and new cells keep forming even though they are not needed by the body, eventually forming a mass of tissue (made up of these extra cells) that is called a tumor. These rapidly reproducing cells also invade normal, healthy cells and tissues in the body; cancer cells are also spread to other areas of the body by the blood and lymph system. There are over 100 types of cancer, with most cancers named for the type of cell that first mutates or changes and begins to divide without control or for the organ of the body in which it starts. There are main categories into which cancers are placed based on their origin and/or the body system in which they begin. Examples are:
- Carcinomas: Cancers that begin in the skin or in other body tissues that line or cover internal organs.
- Sarcomas: Cancers that originate in connective or supportive tissues of the body (including bone, cartilage, fat, muscle, and blood vessels).
- Leukemias: These cancers begin in cells/tissues involved in formation of blood cells (like the bone marrow), and abnormal blood cells are then produced and enter the bloodstream (and therefore circulate throughout the body, crowding and/or replacing normal, healthy blood cells).
- Lymphomas and myelomas: Cancers that begin in cells of the body’s immune system.
- Central Nervous System cancers: These cancers originate in brain or spinal cord tissue.
Treatment of cancer is specific to the type of cancer, sometimes even to characteristics of the cancer cells that are determined through blood testing. Common treatment options for cancer include chemotherapy, radiation, and surgery (usually surgery to remove the tumor or group of cancer cells).
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