Cancer is an illness that develops when the body’s cells begin to grow and divide without control. In most cases, this happens because of changes (mutations) in genes. Mutations are sometimes inherited, but most of the time they occur after birth. Cancer can start in any type of cell and it can spread to other parts of the body, where it grows into a mass (tumor) that may cause symptoms or may press on nearby organs.
Normally, the body makes new cells as needed and old ones die when they are no longer needed. Cancer cells grow and divide out of control and don’t die when they should. The buildup of extra cells forms a mass, or tumor. Some cancers, such as those of the blood and bone marrow, don’t form a solid tumor but can still grow and spread to other parts of the body.
A diagnosis of cancer is usually made by taking a sample of the tumor to look for cancer cells. If the doctor finds cancer cells, a biopsy is done to find out whether or not they are malignant, which means they can spread to other parts of the body. If a person has cancer, doctors treat it with surgery, radiation therapy, chemotherapy or other medicines.
Most types of cancer can be treated if they are found early enough. Often, this means that a tumor can be removed surgically or if the cancer is confined to one part of the body, it can be killed with radiation or other treatments. But even if cancer is not curable, treatment can help control its growth and spread, reduce symptoms and improve a person’s quality of life.
The word cancer comes from Hippocrates, who noticed that long, distended veins near some tumors looked like the legs of a crab. The medical community has learned a great deal about cancer since Hippocrates’ time. Scientists now know that cancer is a complex disease caused by many different things. Cancer can start in any of the body’s cells, which are the basic building blocks of the body.
Cells can be damaged by many factors, including radiation, chemicals, tobacco, alcohol and viruses. These can damage the genes that control how cells work, making them more likely to mutate into cancer cells. In some people, this process of gene mutation is accelerated by the normal aging process.
The most common type of cancer starts in cells that line the inside and outside of the body’s organs. This includes the skin, stomach and lungs. Other types of cancer can begin in bones, blood vessels and lymph nodes.
Many things can reduce a person’s risk of getting cancer, including healthy eating patterns that include lots of vegetables, fruits, whole grains and lean proteins; avoiding foods high in added sugar and saturated fat; and being physically active. But no single food, nutrient or vitamin can prevent cancer.