The human body can find and fix abnormal cells. Sometimes these abnormal cells form a clump that does not spread to other parts of the body and may not need treatment. This is called a benign tumor. Warts are one example of a benign tumor.
The study of cancer and its treatment is called oncology. Doctors who specialize in cancer care are called oncologists.
What is Cancer?
When abnormal cells grow out of control, this is called cancer. When cancer cells clump together, this is called a malignant tumor. At times, these cancer cells can invade nearby tissue. Some cancers do not form tumors. For example, leukemia is a cancer of the bone marrow and blood that does not form a tumor.
When cancer spreads from where it started to another part of the body, this is called metastatic cancer.
Cancer Risk by Age and Race
Cancer risk can go up as people age. The body's repair process may not work as well over time. People also have more time to be exposed to illness and things in the environment that can cause cancer.
Seventy percent of cancer deaths happen in adults aged 65 and older. The average age when cancer is found is 66. The average age at death from cancer is 72.
Black Americans have a cancer death rate that is about 15 percent higher than White Americans. Black cancer death rates are twice as high as those of Hispanic Americans, Asian Americans, and Native Americans.
Common Cancers in Older Adults
- Breast cancer (most common in women)
- Prostate cancer (most common in men)
- Lung cancer
- Colorectal cancer
Some cancers, like breast cancer, are less aggressive in older adults.
Last Reviewed and Updated: October 2026
By: AGS/HiAF Public Education Committee, HealthinAging.org Content Reviewers