A tumor (TOO-mor) is an abnormal growth of new tissue that can occur in any of the body's organs. Many people automatically associate tumors with the disease called cancer * but that is not always the case.
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What Is a Tumor?
The human body is made up of many types of cells that are constantly dividing to produce new, younger cells that can "take over" for aging or damaged cells. Through this process, the body heals its injuries and keeps tissues healthy. Sometimes, this process gets out of control, and new cells continue to be produced even when they are not needed, forming a clump of extra tissue, a tumor.
There are two types of tumors:
- malignant (ma-LIG-nant), or cancerous, tumors are made up of abnormally shaped cells that grow quickly, invade nearby healthy tissues, and often make their way into the bloodstream. When these cells travel to other parts of the body, they form additional tumors.
- Benign (be-NINE) tumors are not cancer. They grow slowly and are self-contained; that is, they do not invade and destroy the tissue around them, nor do they spread to other parts of the body. Their cells are usually normally shaped.
* cancer is any tumorous (TOO-morus) condition, the natural (untreated) course of which is fatal.
Who Gets Tumors?
People of all ages can develop tumors, but generally they are more common as people grow older. Researchers believe that malignant tumors result from a combination of causes, the most important being genetic and environmental. People may inherit a tendency to develop certain kinds of tumors from their parents. Also, repeated exposure to harmful sub-stances such as cigarette smoke, pollutants, and too much sunlight can damage cells and trigger the process of tumor formation.
When a tumor first starts to develop, it is so small that it does not cause symptoms. As it grows, it usually causes symptoms that vary according to its location. For instance, a tumor in the lung may cause a feeling of irritation or a nagging cough. People with brain tumors may experience headaches, dizziness, blurry vision, or lack of coordination. A person with a tumor in the colon * may notice that going to the bath-room is painful or produces blood.
How Are Tumors Diagnosed and Treated?
A doctor can usually diagnose a tumor with one of many tests that create images of the inside of the body, such as x-rays, ultrasound * , CT scans * or MRI * . The next step is to figure out whether the tumor is benign or malignant through a process called biopsy (BY-op-see). Surgeons remove part or all of the tumor and examine a sample under the microscope. The appearance of the cells will indicate whether a tumor is cancerous or not.
Even though a benign tumor is not harmful, it may have to be removed if it causes pain, pressure, or other symptoms. In many cases of a malignancy, the tumor and any affected surrounding tissue will be removed. Sometimes, radiation therapy (directed high-energy x-rays) or chemotherapy (cancer-fighting drugs) may be used to shrink the tumor.
* colon is part of the large intestine where waste is formed and moved to the rectum, which stores it until it passes out of the body.
* ultrasound is a painless procedure in which sound waves passing through the body create images on a computer screen.
* CT scans or CAT scans are the shortened names for computerized axial tomography (to-MOG-ra-fee), which uses computers to view structures inside the body.
* MRI, which is short for magnetic resonance imaging, produces computerized images of internal body tissues based on the magnetic properties of atoms within the body.
The National Cancer Institute, part of the U.S. National Institutes of
Health (NIH), has a fact sheet,
What You Need to Know about Cancer,
and a book,
When Someone in Your Family Has Cancer,
available by phone or on its website at the pages given below. For the
latter, from the Publication Index, follow the link Living with
Cancer/Supporting People with Cancer.