What Cancer Is

3. What Cancer Is

Cancer is the end point (the seventh stage) of a disease process. It is a group of “diseases” found in all races and ages of man and in all animal species. It is often considered a single disease only in the sense that all cancer is characterized by unrestrained growth of unintegrated cells.

Most body structures are composed of tissues made up of many different types of cells, any of which may become cancerous if any unhealthful lifestyle is carried on. A specific type of cancer draws its name from the type of cell affected:

Cancers in connective tissue, including bones, are called sarcomas.

Cancers in cells which line the body’s internal and external surfaces (lungs, breast, skin) are called carcinomas.

Cancers in cells that compose the blood-forming system are called leukemias or lymphomas.

In most cases of cancer, unrestrained cell growth leads to the buildup of tumors which compress, invade, and/or destroy normal tissues. The specific type of tumor may (but not always) indicate a probable causative agent: for example, mesothelioma, a diffuse cancer of the chest or stomach lining, is associated almost exclusively with exposure to asbestos.

Malignant tumors generally share some characteristics: higher rate of cell growth than in the normal, surrounding tissues; failure to maintain the boundaries of normal tissue and organs; a microscopic appearance which suggests immature rather than mature tissues, and a tendency to spread to parts of the body distant from the original site of the cancer. Not all these features accompany every malignant tumor, but they characterize most forms of cancer.