The four standard cancer treatments are surgery, radiation, chemotherapy and biological therapy with hormones and other biological agents. Each is designed to remove or kill the malignant cells and can be used either to affect a cure or to relieve severe symptoms. Surgery and radiation destroy cancer cells locally, while chemotherapy and biological therapy uses drugs to kill cancer cells that spread through the body.

Because chemotherapy and radiation can affect healthy as well as diseased cells, they typically cause side effects. With chemotherapy, side effects may include nausea, vomiting, fatigue, temporary hair loss, mouth sores or dryness, difficulty swallowing, diarrhea, and increased vulnerability to infection. Radiation may have some of the same effects, depending on the area of the body that is irradiated, as well as irritation to the overlying skin. Medication can help curb side effects during treatment, and most side effects resolve when the treatment is concluded.

Hormone therapy is standard treatment for some types of cancers that grow faster in the presence of particular hormones like cancer of the breast, prostate, or uterus. By blocking either the production or the action of the hormones, this therapy slows tumor growth and may extend survival for several months or even years.

Although still largely experimental, immunotherapy is emerging as another mode of cancer treatment, with the goal of destroying cancer cells without affecting healthy cells. It does not attack cancer cells directly but employs various techniques to manipulate the body's immune system into fighting cancer more aggressively.

Gene therapy is a subcategory of immunotherapy which manipulates genetic material inside either cancerous cells or the immune cells intended to attack them, in order to make the cancer cells easier targets. Immunotherapy and other experimental treatments generally are reserved for patients with metastatic or recurrent disease, who have not responded well to standard treatment.

As cancer advances, pain may become a significant problem. Fortunately, moderate to severe cancer pain can be managed effectively with prescription medication, such as codeine and morphine. Addiction does not occur with opioid drugs given for true pain, and research shows that people in less pain respond better to treatment and enjoy better quality of life.

The ultimate goal of cancer treatment is to relieve pain and other symptoms, maintain general health, and provide emotional, psychological, and logistical support to patients and their families. Similar supportive treatment is available to rehabilitate patients after curative treatment. Supportive therapy such as hospice care for cancer patients nearing the end of their lives provides relief from pain and other irreversible symptoms. Most mainstream care is geared toward providing supportive treatment through the broad resources of a cancer treatment center. The best complementary cancer therapies, which are generally provided outside a hospital, also provide excellent supportive care.