Knowing what chemotherapy does, and when and how it is given, may make you feel less anxious about starting treatment. Chemotherapy can be a single medication or a combination of medications. It may be used along with surgery or radiation therapy to shrink a tumor or prevent its spread.

Chemotherapy kills growing cancer cells. More than one medication may be used. This allows the growing cells to be attacked at more than one stage of growth. Side effects occur because chemotherapy acts on normal cells, too. Fast-growing cells are most affected. This includes cells that make up hair, the digestive tract, and blood. Chemotherapy is given in cycles. After a treatment, time is set aside for the body to build healthy cells before the next cycle begins.
Chemotherapy can reduce the number of cancer cells. As a result, it may:
Cure cancer
Cause remission (no active symptoms of disease)
Kill any cancer cells remaining after surgery
Control cancer for a period of time
Reduce symptoms (such as pain)
There are some risks with chemotherapy, but the benefits usually outweigh the risks. The following are possible long-term side effects of some types of chemotherapy:
Lasting nerve damage
Another cancer, which may occur at a later time