Cancer is a broad term used to describe many different diseases. In general, cancer happens when abnormal cells in your body grow out of control and crowd out normal cells.
It can start almost anywhere. Cancer can stay in one spot, or it can metastasize — spread throughout your body. Some cancers grow slowly, while others grow quickly.
Most cancers are named for where they start in the body. For instance, “breast cancer” begins in your breast tissue.
Many cancers form solid tumors, which are growths of tissue. But blood cancers, such as leukemia, don’t generally grow as tumors; they stay in the form of individual cells. Tumors can be either malignant (cancerous) or benign (noncancerous).
Prevalence: Cancer Is a Common Disease
According to the National Cancer Institute, more than 1.6 million new cases of cancer are diagnosed in the United States each year. About 597,690 people die from some form of the disease annually. (1)
Data also shows that more than 38 percent of men and women will be diagnosed with a form of cancer at some point in their lives. (2)
