What is chemotherapy?

PearlPoint Cancer Support
Chemotherapy (chemo) uses medicines that destroy cancer cells or prevent them from dividing and spreading. Chemotherapy affects your whole body because it goes through your bloodstream. Chemotherapy doesn’t refer to one treatment, but many. There are a lot of different types of chemotherapy medicines. Some targeted therapies are also considered chemotherapy.
Chemotherapy involves a combination of anticancer drugs. These drugs are powerful and can have many side effects. Anticancer drugs are given by mouth or by injection into a blood vessel. Either way, the drugs enter the bloodstream and travel throughout the body.

Chemotherapy is given in cycles: a treatment period followed by a recovery period, then another treatment period, and so on. Most people receive treatment in an outpatient part of the hospital or at the doctor's office. Adjuvant chemotherapy usually lasts for three to six months.
Penn Medicine
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). The way the chemotherapy is given depends on the type and stage of the cancer being treated.
Chemotherapy (chemo) is the treatment of cancer with drugs that destroy cancer cells and tumors. Prostate cancer chemotherapy is typically reserved for patients whose cancer has metastasized to the bone or elsewhere in the body.

In some cases, chemo may be used in conjunction with other treatments, such as radiation, for the treatment of localized prostate cancer. In these cases, a low-dose chemotherapy is used to sensitize the cancer cells to radiation therapy.
Chemotherapy (also called chemo) is sometimes used alone or in conjunction with other treatments such as radiation or surgery. It is a conventional medical strategy that can help:
  • Destroy cancer cells
  • Shrink tumors
  • Stop cancer cells from multiplying or growing

Healthy cells also can be harmed during chemo, which can cause side effects. These cells usually repair themselves after chemotherapy.

How it's used: Chemo is a drug therapy given at home, at the hospital, or at a doctor's office. It is administered either intravenously, orally, through an injection, or by application to the skin. Depending on the type of cancer you have, chemo is used to cure your cancer, control growth, kill cells, and/or to relieve pain and other symptoms.

Side effects: The healthy cells most likely to be affected are found in bone marrow, the reproductive system, the digestive tract, and hair follicles. Your symptoms will depend on the kind and dose of medication you are taking. You may or may not experience fatigue, nausea, pain, hair loss, infection, and/or anemia.

Ajay K. Sahajpal, MD
Transplant Surgery
Chemotherapy refers to the use of medications or medical therapy to "treat" or fight cancers and they typically act to slow cell growth or directly kill actively dividing cells such as cancers. Recently a new term referred to as targeted therapy is applied to molecular marker treatments targeting a specific cell marker on cells as therapy.
Chemotherapy is the use of medication to destroy cancer cells. Sometimes these medications are called anticancer drugs. Chemotherapy also may be used to treat immune system diseases.

Cancer cells divide and grow in a way that is not normal. Chemotherapy stops cancer cells from dividing or growing. It can also help the immune system work more normally. Chemotherapy is used to:
  • Make a tumor shrink before surgery or radiation treatment
  • Destroy cancer cells that may be left after surgery or radiation treatment
  • Help radiation and biotherapy work better
Aurora Health Care
Chemotherapy means treatment with medications or chemicals. Cancer chemotherapy acts on cells that rapidly divide, which includes normal and cancer cells. The chemotherapy interferes with cell reproduction. If the cancer cell can't reproduce, it will eventually die without producing another cell like it. This eventually leads to a decrease of cancer cells.
John A. Chabot
Endocrinology Diabetes & Metabolism
Chemotherapy is the use of medications to fight cancer. It is considered a systemic treatment which means the medication travels through the blood stream and throughout the body to reach the cancerous cells. Chemotherapy works by attacking rapidly dividing cells in the body, interfering with their ability to grow or multiply. Since cancer cells are marked by uncontrolled growth, they are often susceptible to these drugs. However, since chemotherapy is a systemic treatment and affects all rapidly dividing cells in the body, these drugs may also damage some normal cells. The most susceptible normal cells are the blood cells, hair follicles, and the cells lining the mouth and intestines.
Dede Bonner
Health Education

Chemotherapy (also called “chemo”) is a drug-based treatment for cancer.  Knowing what to expect in advance is one of your best weapons in your fight against breast cancer. The more knowledge you have, the more prepared you will be to collaborate with your medical team to make the best decisions about your cancer treatment. You’ll be able to better protect yourself against possible chemotherapy side effects and manage the ones that do occur effectively.

The 10 Best Questions for Surviving Breast Cancer: The Script You Need to Take Control of Your Health

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The 10 Best Questions for Surviving Breast Cancer: The Script You Need to Take Control of Your Health

A good mind knows the right answers...but a great mind knows the right questions. And never are the Best Questions more important than after a diagnosis of breast cancer. Drawing on cutting-edge...

Chemotherapy is the use of anticancer drugs to treat cancerous cells. Chemotherapy has been used for many years and is one of the most common treatments for cancer. In most cases, chemotherapy works by interfering with the cancer cell's ability to grow or reproduce. Different groups of drugs work in different ways to fight cancer cells. Chemotherapy may be used alone for some types of cancer or in combination with other treatments such as radiation or surgery. Often, a combination of chemotherapy drugs is used to fight a specific cancer. Certain chemotherapy drugs may be given in a specific order depending on the type of cancer it is being used to treat.


While chemotherapy can be quite effective in treating certain cancers, chemotherapy drugs reach all parts of the body, not just the cancer cells. Because of this, there may be many side effects during treatment. The ability to anticipate these side effects can help patients and caregivers prepare and, in some cases, prevent these symptoms from occurring.


Chemotherapy can be given:


- as a pill to swallow

- as an injection into the muscle or fat tissue

- intravenously (directly to the bloodstream; also called IV)

- topically (applied to the skin)

- directly into a body cavity


To reduce the damage to healthy cells and to give them a chance to recover, chemotherapy is given in cycles. Chemotherapy may be given daily, weekly, every few weeks, or monthly, depending on a patient's specific situation.

Continue Learning about Chemotherapy For Cancer

Chemotherapy For Cancer

Chemotherapy For Cancer

One of three common treatments for cancer, chemotherapy uses drugs to kill or slow down the progression of cancer cells. Different chemotherapy drugs are used for different types of cancers and can be combined with other treatment...

s, like radiation therapy or surgery. Chemotherapy often causes side effects, such as fatigue, nausea and mouth sores. Most side effects subside after treatment ends; however, some side effects can develop late in treatment and cause long-lasting issues, such as heart and kidney problems, or damage to nerve and lung tissue. Make sure to talk to your oncologist early about these potential side effects. To prepare for chemotherapy, ask your doctor for tests to check your heart and liver functions to make sure you are healthy enough to undergo treatment. Once you're ready for treatment, you may receive the drugs intravenously through a port in your chest, orally by taking a pill or through an injection into a muscle.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.