Chemotherapy, oftentimes shortened to “chemo,” involves the use of drugs to stop tumor growth or slow tumor growth in individuals whose cancer cells have metastasized to other parts of the body beyond the original tumor. It works by interfering with cancer cells’ ability to grow or reproduce.
There are more than 100 drugs used in various combinations in chemo treatment, although even a single drug can be used to treat cancer (though combinations usually work better). The amount and type of chemotherapy drugs will depend on the type of cancer, where it is and how big it is.
While chemotherapy may be used alone in some cases, more often it is combined with surgery and/or radiation therapy in an effort to cure cancer or control cancer—for instance, to shrink a tumor before surgery or radiation, or to kill remaining cancer cells after surgery or radiation. Chemo given after surgery is called adjuvant chemotherapy; chemo given before surgery or radiation is called neoadjuvant chemotherapy. Chemotherapy can also be used in cases in which a cure is not possible; palliative care, as it’s called, is an effort to improve patients’ quality of life in terminal cases. Shrinking the size of tumors can often reduce the symptoms that patients experience.
Most of the time, chemotherapy drugs are given via intravenous (IV) injection. This chemotherapy injection is given through a tiny plastic tube called a catheter. It can be given quickly in a process called an IV push, and IV infusion that lasts 30 minutes to a few hours, or, in some cases, a continuous injection that can last between a day and a week, and controlled by an electronic IV pump.
Chemotherapy can also be given as an oral medication, in which the drug is swallowed as a pill, capsule or liquid; intrathecally, in which the drug is administered into the spinal cord and cerebrospinal fluid, either through an injection or through a long-term catheter and port implanted during surgery; as an intra-arterial (IA) injection, in which the drug is placed directly into an artery to treat a single area, such as the liver, arm or leg); through an intracavitary injection, in which the chemo drug is given through a catheter is the abdominal cavity or chest cavity; as intraperitoneal (IP) chemotherapy, in which the chemo drugs are given directly into the abdomen through a tube; as an intramuscular injection, in which the drug is injected into the muscle; as an intralesional injection, during which the drug is injected directly into a tumor in the skin or an internal organ; and as topical chemotherapy, in which the chemo drug is placed directly on an area of cancer on the skin as a cream, gel or ointment.
Chemotherapy, which can be very effective at killing cancer cells, also kills other, healthy cells, meaning it can have many side effects, including fatigue, nausea and vomiting.