Why it's done

Chemotherapy is used to kill cancer cells in people with cancer.

There are a variety of settings in which chemotherapy may be used in people with cancer:

• To cure the cancer without other treatments. Chemotherapy can be used as the primary or sole treatment for cancer.
• After other treatments, to kill hidden cancer cells. Chemotherapy can be used after other treatments, such as surgery, to kill any cancer cells that might remain in the body. Doctors call this adjuvant therapy.
• To prepare you for other treatments. Chemotherapy can be used to shrink a tumor so that other treatments, such as radiation and surgery, are possible. Doctors call this neoadjuvant therapy.
• To ease signs and symptoms. Chemotherapy may help relieve signs and symptoms of cancer by killing some of the cancer cells. Doctors call this palliative chemotherapy.

Chemotherapy for conditions other than cancer

Some chemotherapy drugs have proved useful in treating other conditions, such as:

• Bone marrow diseases. Diseases that affect the bone marrow and blood cells may be treated with a bone marrow transplant, also known as a stem cell transplant. Chemotherapy is often used to prepare for a bone marrow transplant.
• Immune system disorders. Lower doses of chemotherapy drugs can help control an overactive immune system in certain diseases, such as lupus and rheumatoid arthritis.