Cancer

What is Cancer?

Abnormal breast cell
A breast cancer cell (green) metastasizing through a fibrous layer in the lining of the abdomen (red) by "squeezing" through openings in the fibrous layer. The cell's nucleus is in blue. — Wadsworth Center

Cancer is a group of more than 100 different diseases that are due to abnormal growth of body cells. The human body is made up of billions of tiny cells that reproduce themselves by dividing. Through this normal process of cell division, the growth and repair of body tissue takes place.

When a cell begins dividing irregularly, masses known as tumors can form.

Tumors may be benign (not cancerous) or malignant (cancerous). A malignant tumor, or cancer, can invade nearby tissues and organs. It can spread (metastasize) to other parts of the body forming other tumors. The rate of growth varies. Some cancers grow rapidly; others may grow slowly over a period of many years.

Some cancers are easily curable. However, others are more difficult to cure by the time they are first diagnosed, particularly if the tumor has grown substantially.

What is New York Doing About Cancer?

Data and Statistics

Who gets Cancer?

One in three persons will be diagnosed with cancer some time in their life and it will eventually affect three out of every four families. One in five deaths in the United States is due to cancer. Cancer develops in people of all ages but most often in the middle-aged and the elderly. The number of cancer cases has risen dramatically over the past 40 years, but much of this increase is a reflection of the increase in population, especially in the older age groups.

Researchers do not fully understand why some people develop cancer while others do not. Susceptibility to cancer-causing agents probably varies among individuals due to genetic factors. Other factors, as yet unknown, may also play a part in causing this disease.

What causes Cancer?

No one knows for certain how a normal cell becomes a cancer cell. Many causes of cancer have been identified. Scientists agree that one way people can get cancer is through repeated long-term contact with one or more cancer-causing agents (carcinogens). Such agents include tobacco, sunlight, X-rays and certain chemicals that may be found in air, water, food, drugs and the workplace.

Factors associated with our personal habits and lifestyle are believed to contribute to the majority of cases. For example, it has been estimated that approximately 30 percent of all cancer deaths are directly related to the use of tobacco. Some cancer risk may be related to diet.

What are the most common types of cancer?

Cancers of the prostate, lung and colon are the most common types diagnosed among adult males. Breast, lung and colon cancers are the most common among females. Common sites of metastatic cancer (cancer that has spread from the primary site) include the brain and liver.

Skin cancers are actually the most common form of cancer for both men and women.

Learn more about the different types of cancer

Learn more about cancer