What does chemotherapy do ?

It depends on the kind of cancer you have and how far along it is.

Cure: In some cases, the treatment can destroy cancer cells to the point that your doctor can no longer detect them in your body. After that, the best outcome is that they never grow back again, but that doesn’t always happen.
Control: In some cases, it may only be able to keep cancer from spreading to other parts of your body or slow the growth of cancer tumors.
Ease symptoms: In some cases, chemotherapy can’t cure or control the spread of cancer and is simply used to shrink tumors that cause pain or pressure. These tumors often continue to grow back.

How is chemotherapy used ?

Sometimes, it treats cancer by itself, but more often it’s used in combination with:

Surgery: A doctor removes cancerous tumors or tissue, or organs contaminated with cancerous cells.
Radiation therapy: A doctor uses invisible radioactive particles to kill cancer cells. It may be delivered by a special machine that bombards parts of your body from the outside, or by putting radioactive material on, near, and even inside your body.
Biological therapy: Living material in the form of bacteria, vaccines, or antibodies are carefully introduced to kill cancer cells.