There are more than 100 types of cancer, all characterized by the uncontrolled growth and spread of abnormal cells that have the potential to invade and destroy normal body tissue. At first, most solid cancers are localized, with cancer cells confined to their original site. However, over time, these cancer cells may spread, or metastasize, to other parts of the body. Some less common cancers of the bloodstream, such as leukemia, involve the body more generally at the time of presentation. The most common cancer types that lead to death include lung, breast, colorectal, and prostate. Treatments for cancer can be most effective when the cancer is localized; once cancer has spread, treatment is more difficult and less effective.
More than 1.6 million new cases of cancer are diagnosed in the United States each year, and close to 600,000 Americans die from cancer annually. Deaths from cancer have decreased over the last 20 years (by 1.8 percent among men and 1.4 percent among women) but still remain higher for African Americans than for non-Hispanic/Latino whites, reflecting differences in genetics, environmental exposure related to socioeconomic status, and health care disparities. Paralleling these differences, the five-year survival rate for cancer in African Americans is significantly lower than for non-Hispanic/Latino whites, due in large part to diagnosis occurring later in the disease process.