As of January 1, 2016, an estimated 15.5 million people with a history of cancer are living in the United States. February 4 is World Cancer Day. Cancer has affected almost every family in the country in some way, but many people do not understand exactly what cancer is, what causes it, and how it is treated. Here is a general overview of cancer:

What is cancer?
Cancer is the broad term to describe the disease that results when cellular changes cause the uncontrolled growth and division of cells. Most of the cells in the body have specific functions and fixed lifespans. Cancerous cells lack the components that instruct them to stop dividing and to die, so they continue to replicate and build up in the body, which uses up the oxygen and nutrients that could be used to nourish other cells. Cancerous cells can form tumors, impair the immune system and cause other changes that prevent the body’s natural functions.

What causes cancer?
There are several causes of cancer, and some of them are preventable.

480,000 people in the U.S. die each year from smoking cigarettes. Other risks factor for cancer include heavy alcohol consumption, excess body weight, physical inactivity and poor nutrition. One of the most significant unpreventable risk factor is age. About 87 percent of cancer cases occur in people ages 50 years or older.

Certain genetic factors can contribute to the development of cancer. The genetic code of a person tells their cells when to divide and when to die. Changes in these genes can lead to faulty instructions, which may result in cancer. People can also inherit a predisposition for certain types of cancer.

How is cancer treated?
Medical professionals will give treatment to a cancer patient based on the type of cancer, its stage of progression, and the person’s overall health. Some of the most common approaches to cancer treatment are chemotherapy, hormone therapy, radiation therapy, and surgery.

Chemotherapy is a method of cancer treatment that aims to kill cancerous cells with a medication that targets cells that are dividing rapidly. The drugs can help shrink tumors but has many harsh side effects.

Hormone therapy involves taking medications that change how certain hormones work in the body. With cancers in which hormones play a significant role, such as prostate and breast cancers, this treatment is a common approach.

Radiation therapy uses high-dose radiation to kill cancerous cells. A doctor may recommend using radiation to shrink a tumor before surgery or reduce the symptoms of a tumor.

When a patient has a cancerous tumor, surgery is often part of the treatment plan. A surgeon may also remove lymph nodes to reduce or prevent a disease spread.

Cancer treatments are constantly improving and advancing. It’s important to discuss with your physician your risk factors for cancer, and seek to live a healthy lifestyle to reduce your risks. For more information about cancer, visit