Types of Cancer
Understanding Cancer
Cancer comes in many forms, depending on the type of tissue in which it develops. The classifications break down into five categories:
- Carcinoma - a tumor that begins in the cells that line the surface of our skin, organs, digestive tract and airways. Because those surfaces are exposed to external agents such as chemicals, solar radiation, smoke and others, carcinomas make up about 80 to 90 percent of all cancers.
- Sarcoma - a tumor that begins in bone, cartilage, fat, muscle, blood vessels, or other connective tissue.
- Leukemia - cancer of the white blood cells or their precursors that typically begins in the bone marrow and causes abnormal blood cells to move into the bloodstream.
- Lymphoma - cancers that begin in the lymphatic cells (lymphocytes); which are found in lymph nodes and the spleen, as well as other organs such as the breast, brain and stomach.
- Myeloma - cancers that begin in blood plasma cells responsible for producing antibodies.
- Mixed Types - although uncommon, some cancers can stem from a combination of types within the same category or from two or more categories.
It's also important to know that many different types of cancer may start in a primary location. Though we many commonly refer to a cancer as lung cancer, it may be small cell lung cancer or one of three types of carcinomas that fall under the category of non-small cell lung cancer. The same is true for most cancers named for the primary site the cancer develops. Leukemia, for example, may be a form of acute (acute lymphoblastic leukemia or acute myelogenous leukemia) or chronic (chronic lymphoblastic leukemia, chronic myeloid leukemia or hairy cell leukemia). Because each cancer is named depending on the type of cells involved, treatments are designed specifically to address each type. A treatment that is effective to treat one type of leukemia may not prove effective for another.
