Comprehensive Cancer Care Services

Overview of Cancer | What is Cancer?

Cancer is a group of many related diseases that begin in the cells of the body, which are the basic unit of life. To understand cancer, it is helpful to know what happens when normal cells become cancerous.

The body is made up of many types of cells. Under normal circumstances, cells grow and divide in order to produce more cells, however, only when the body needs them. This process helps keep the body healthy. Sometimes cells keep dividing when new cells are not needed. These extra cells form a mass of tissue, called a tumor.

Tumors can be benign or malignant.

• Benign tumors are not cancer. They can often be removed and, in most cases, they do not come back. Cells from benign tumors do not spread to other parts of the body. Most important, benign tumors are rarely life threatening.
• Malignant tumors are cancer. Cells in these tumors are abnormal and divide without control or order. They can invade and damage nearby tissues and organs. Cancer cells can break away from a malignant tumor and enter the bloodstream or the lymphatic system. This is how cancer spreads from the original cancer site to form new tumors in other organs. The spread of cancer is called metastasis.

Leukemia and lymphoma are cancers that arise in blood-forming cells. The abnormal cells circulate in the bloodstream and lymphatic system. They may also invade (infiltrate) body organs and form tumors.

Most cancers are named for the organ or type of cell in which they begin. For example, cancer that begins in the lung is lung cancer, cancer that begins in the breast is breast cancer, and cancer that begins in cells in the skin known as melanocytes is called melanoma.

When cancer spreads (metastasizes), cancer cells are often found in nearby lymph nodes. If the cancer has reached these nodes, it may also mean that cancer cells have spread to other organs, such as the liver, bone, or brain. When cancer spreads from its original location to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary tumor. For example, if lung cancer spreads to the brain, the cancer cells in the brain are actually lung cancer cells. The disease is called metastatic lung cancer (it is not brain cancer).

Possible Causes & Prevention of Cancer

Even though doctors can seldom explain why one person gets cancer and another does not, it is clear that cancer is not caused by an injury, such as a bump or bruise. And although being infected with certain viruses may increase the risk of some types of cancer, cancer is not contagious; no one can “catch” cancer from another person.

Cancer develops over time. It is a result of a complex mix of factors related to lifestyle, heredity, and environment. Some cancer risk factors can be avoided. Other cancer risk factors which are inherited are unavoidable, but it may be helpful to be aware of them. People can help protect themselves by avoiding known risk factors whenever possible. Tobacco, diet, ultraviolet light, alcohol consumption, hormone replacement therapy, and family history are known risk factors which increase the likelihood of cancer.