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What is a chemotherapy regimen?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Oct 29, 2021.

Official answer


A chemotherapy (chemo) regimen consists of anti-cancer medicines you receive over a set period of time (over several cycles). Chemo regimens, such as R-CHOP, are often abbreviated by using the first letter of the drug names. For example, R-CHOP is an abbreviation for a 5-drug chemotherapy regimen used to treat non-Hodgkin’s lymphoma, a type of blood cancer.

The R-CHOP regimen consists of:

An induction regimen (or induction therapy) is the first cancer treatment you receive, and may involve chemotherapy, surgery or radiation. It may also be called first-line therapy, primary therapy, and primary treatment.

A maintenance regimen (or maintenance therapy) is the ongoing treatment given to help the cancer from coming back after your first therapy. You may receive this regimen for a longer period of time, and it can include drugs, vaccines or antibodies.

Chemotherapy kills or slows the growth of the primary tumor and other cancer cells that may have spread in the body (metastasized). Many chemotherapy drugs are combined because they kill cancer cells in different ways and may be more effective. Chemotherapy drugs reach almost all areas of the body.

You may receive your chemotherapy as an intravenous (IV) infusion into your vein at a clinic, the hospital or at home. When given at an infusion clinic, you typically go home the same day, but you may need to spend several hours at the clinic for the treatment and lab work. Your doctor, nurse or pharmacist will tell you how long you need to stay at the clinic each time.

Your cancer regimen may also involve taking oral drug treatments (pills) or regular injections under your skin or into your muscle. Your doctor may adjust your regimens over time based on how you respond.

Treatment is specific for each patient and depends on factors such as the stage of cancer at diagnosis, previous treatments and how well you have tolerated other treatments.

What is a chemotherapy cycle?

A chemotherapy cycle is the time from when you receive your cancer treatment until the end of a rest period with no treatment. The time between your first day of chemotherapy and your last rest day is one cycle. The rest period allows your body to recuperate from some side effects of the anti-cancer medicine. The cycle is repeated on a regular schedule. The first day you receive the chemotherapy is Day 1 of the treatment cycle.

For example, with the R-CHOP regimen, a cycle is commonly given every 21 days for 6 cycles, meaning this regimen is given over several months. Different regimens will have a different numbers of cycles and length.

To learn more, join the Chemotherapy Support Group to keep up with FAQs on cancer treatment, read the latest news, and to get and give help to a like-minded community.


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