A Quick Guide to Cancer Basics
Cancer can originate in just about any part of the body. Although there are over 100 types of cancer, these can be grouped into five broader categories. These include:
- Carcinoma: These are the most common types of cancer that start in the skin or in the tissues that cover internal organs. In the United States, the most common types of carcinomas are lung, breast, and colon cancer.
- Sarcoma: A type of cancer that starts in the bone, cartilage, fat, muscle, blood vessels, or other connective tissue.
- Leukemia: A type of cancer that begins in the blood-forming tissue, such as the bone marrow, and causes a significant amount of abnormal blood cells to be made and enter the blood.
- Central nervous system cancers: Cancers that begin in the tissues of the brain and spinal cord.
- Lymphoma and myeloma: Cancers that start in the lymph nodes and cells of the immune system.
Diagnosing cancer early can play a critical role in the outcome of this disease. However, being diagnosed with cancer doesn't happen all at once -- it is a process. Once cancer is found, your healthcare provider will determine what type it is and how fast it is growing.
It will also be important to determine whether the cancer cells have invaded nearby healthy tissue or spread (metastasized) to other areas of the body. In some cases, diagnosing cancer early may decrease a person's risk of death from the disease.
Although your healthcare provider may diagnose you with cancer, the grade and other cellular factors will not be known until a sample of the tumor is examined. In many cases, this may not happen until after surgery is done to remove the primary tumor, if possible. This surgical removal of a piece of tissue is called a biopsy. The tissue is then examined under a microscope to determine whether a tumor is actually present and whether it is malignant (cancerous). Cancer cells have a distinctive appearance under the microscope -- irregularly shaped dividing cells.