What is chemotherapy and how does it work?

Chemotherapy is the use of medicines or drugs to treat disease. Many times this treatment is just called "chemo." Surgery and radiation therapy remove, kill, or damage cancer cells in a certain area, but chemo works throughout the whole body. Chemo can kill cancer cells that have metastasized or spread to parts of the body far away from the primary (original) tumor.

More than 100 chemo drugs are used in many combinations. A single chemo drug can be used to treat cancer. But for the most part, the drugs work better when used in certain combinations. Your chemo treatment will likely include more than one drug. This is called combination chemotherapy. A combination of drugs with different actions can work together to kill more cancer cells. It can also reduce the chance that the cancer may become resistant to any one chemo drug.

You and your doctor will decide what drug or combination of drugs you will get. Your doctor will choose the doses, how the drugs will be given, and how often and how long you will get treatment. All of these decisions will depend on the type of cancer, where it is, how big it is, and how it is affecting your normal body functions and overall health.

What is the goal of chemo?

Depending on the type of cancer and its stage (if and how far it has spread), chemo can be used to:

• Cure the cancer.
• Keep the cancer from spreading.
• Slow the cancer's growth.
• Kill cancer cells that may have spread to other parts of the body from the original tumor.
• Relieve symptoms caused by cancer.

Your doctor will talk to you about the goal of your chemo before you start treatment.

Will chemo be my only treatment for cancer?

Sometimes chemo is the only treatment you need. More often, chemo is used along with surgery or radiation therapy or with both. Here's why:

• Chemo may be used to shrink a tumor before surgery or radiation therapy.

• It may be used after surgery or radiation therapy to help kill any remaining cancer cells.

• It may be used with other treatments if your cancer comes back.

When chemo is given after surgery to kill any cancer cells that may still be present, it is called adjuvant therapy. When chemo is used to shrink a tumor before surgery or radiation therapy, it is called neoadjuvant therapy.

A checklist of questions to ask your doctor or nurse

Before choosing chemo as a treatment option, you should understand the expected benefits, side effects, and risks. Consider asking your doctor or nurse the questions below. It may help you to write down questions to take with you to your next visit. Learn as much as you can from reliable sources about your treatment, and get an idea of the expected outcome.

• What is the goal of chemo for my cancer?

• What are the chances that the chemo will work?

• After chemo, will I be cured, in remission, or have fewer symptoms?

• Are there other ways to get to the same goals?

• How will I know if the chemo is working?

• If the chemo does not work, are there other treatments for me?

• What are the risks and side effects of the chemo I will be taking? How do side effects of this chemo compare with side effects of other treatments?

• How will I get the chemo, how often, and for how long?

• Where will I get chemo?

• What can I do to get ready for treatment and decrease the chance of side effects?

• Will I need to change my diet in any way? My activities? My work? Exercise? Sexual activities?

• Will I also need surgery, radiation, or both? If so, when and why? What results can I expect from each type of treatment?

• If I have chemo after surgery or radiation, will it kill any remaining cancer cells? Could chemo be used alone?

• Could I take part in a clinical trial?

• How much will chemo cost? Will my health insurance cover it?

• If the insurance company asks for a second opinion, or if I would like to get one, can you suggest someone for me to see?

Here are some tips to help you remember your doctor's answers:

• Take notes during your visits. Don't feel shy about asking your doctor to slow down if you need more time to write. Ask questions if you don't understand something.

• If you can, use a tape recorder during your visit so you won't miss anything. But first ask your doctor if it is OK to tape your talks.

• Consider taking a friend or relative with you to help you understand what your doctor says during your visit and to refresh your memory afterward.

You might want to look at our booklet called After Diagnosis: A Guide for Patients and Families for more ideas about the things you and your family may want to know.

Should I get a second opinion?

One way to find out if a suggested treatment is the best one for you is to get the opinion of at least one other doctor before starting treatment. Your doctor should not mind if you get a second opinion. In fact, some insurance companies require you to get one. Often, the results of any tests you have already had can be sent to the second doctor, so you won't have to repeat them.

If your insurance is provided by a managed care group, like a health maintenance organization (HMO), find out if the company covers second opinions before you get one.

Where will I get chemo?

The place you get your treatment depends on which chemo drugs you are getting, the drug doses, your hospital's policies, your insurance coverage, what you prefer, and what your doctor recommends.

You may be treated with chemo:

• At home
• In your doctor's office
• In a clinic
• In your hospital's outpatient department
• In a hospital

Some of these settings may have private treatment rooms, while others treat many patients together in one large room. It is important to be in a setting that is comfortable for you. Talk to your doctor ahead of time so that you know what to expect your first day.

How often will I need to get chemo and how long will it last?

How often you get chemo and how long your treatment lasts depend on the kind of cancer you have, the goals of the treatment, the drugs being used, and how your body responds to them. You may get treatments daily, weekly, or monthly, but they are usually given in on-and-off cycles. These breaks allow rest periods so that your body can build healthy new cells and regain its strength.

Many people wonder how long the actual drugs stay in their body and how they are removed. Most chemo drugs are broken down by your kidneys and liver and then removed from your body through your urine or stool. The time it takes your body to get rid of the drugs depends on many things, including the type of chemo you get, other medicines you take, your age, and your kidney and liver functions. Your doctor will tell you if you will need to take any special precautions because of the drugs you are getting. (See "How can I protect myself and those I live with while I am getting chemo?" for general safety tips to follow at home.)

If your cancer comes back, chemo may be used again. This time, you may be given different drugs to relieve symptoms or to slow the cancer's growth or spread. Side effects may be different, depending on the drug, the dose, and how it is given.

How will the chemo be given to me?

Most chemo drugs are given through a tiny plastic tube called a catheter. A needle is used to put the catheter into a vein in your forearm or hand; then the needle is taken out, leaving the catheter behind. This is called intravenous, or IV treatment. Intravenous drugs are given in these ways:

• The drugs can be given quickly through the catheter right from a syringe over a few minutes. This is called an IV push.

• An IV infusion can last 30 minutes to a few hours. A mixed drug solution flows from a plastic bag through tubing that is attached to the catheter. The flow is often controlled by machine called an IV pump.

• Continuous infusions are sometimes needed and can last from 1 to 7 days. These are always controlled by electronic IV pumps.

The needles and catheters can scar or weaken veins with ongoing chemo. Another option is the central venous catheter (CVC). The CVC is a bigger catheter that is put into a large vein in the chest or upper arm during surgery. It stays in place so that IV medicines can be given more easily. Blood can also be drawn from these catheters. A number of different kinds of CVCs are available. Many people talk about this option with their doctor even before starting treatment. Some find out during treatment that they need a CVC because their hand and arm veins are not good enough to complete the planned chemo. Your doctor can help you decide if you need a CVC, and the right type of CVC for you.

Depending on the drugs and where the cancer is located, your chemo also may be given in one or more of these ways:

• Orally or PO – This means by mouth. You swallow the drug as a pill, capsule, or liquid – just as you do other medicines. This is usually more convenient and may cost less because the drugs can often be taken at home. If you take chemo drugs by mouth, it is very important to take the exact dosage, at the right time, for as long as it has been prescribed for you. For more information please call us and ask for Oral Chemotherapy: What You Need to Know.

• Intrathecal or IT – The drug is put into the spinal canal and goes into the fluid that surrounds your brain and spinal cord. This fluid is called the cerebrospinal fluid (CSF). You may either have a needle put right into your spine to quickly give the drug, or a long-term catheter and port can be put under the skin on your head during surgery. This is called an Ommaya reservoir. The port is a small drum-like device that has a small tube attached to it. The tube goes in to the cerebrospinal fluid (CSF) in your spinal canal. It stays in place under your skin until treatment is done.

• Intra-arterial – The chemo drug is put right into an artery to treat a single area (such as the liver, an arm, or leg). This method limits the effect of the drug on other parts of the body.

• Intracavitary – Chemo drugs may be given through a catheter into the abdominal cavity (the space around the bowels and other organs in the belly) or chest cavity (the space around the lungs and other organs in the chest).

• Intramuscular or IM – The drug is put in through a needle into a muscle (as a shot).

• Intralesional – A needle is used to put the drug right into a tumor in the skin, under the skin, or in an internal organ.

• Topical – The drug is put right on to an area of cancer on the skin.

Does chemo hurt?

You already know how it feels to take a pill or rub a medicine on your skin. And you've probably felt the slight but brief discomfort of a shot (or an injection) before. IV medicines should not hurt after the first needle stick to put in the catheter. If you feel pain, burning, coolness, or anything unusual while you are getting chemo, tell your doctor or nurse right away.

What are clinical trials?

Clinical trials are carefully designed research studies that test promising new cancer treatments. You may want to talk to your doctor about this option. Patients who take part in research studies will be the first to benefit from these treatments. These patients can make an important contribution to medical care because the study results will also help other patients. In a clinical trial, you get either standard treatment or a new treatment that is thought to be as good as – or maybe better than – the standard treatment. Studies are never done to see if you would recover from cancer without treatment at all. As with any other medical treatment, you are free to withdraw from a clinical trial at any time and seek other treatment options.

To learn more about clinical trials:

• See our document on clinical trials called Clinical Trials: What You Need to Know.

• The American Cancer Society also offers a Clinical Trials Matching Service to help you find clinical trials that might be right for you. The service is available by telephone from 7:30 a.m. until 7:00 p.m. CT Monday through Friday at 1-800-303-5691, or you can fill out a screening questionnaire anytime at www.cancer.org/clinicaltrials.

• The National Cancer Institute (NCI) can give you a list of clinical trials based on the type and stage of your cancer. Call 1-800-422-6237, or visit the NCI's Web site at www.nci.nih.gov.

Can I take other medicines while I am getting chemo?

Some medicines may interfere with the effects of your chemo. To be sure that your treatment works as well as it can, tell your doctor or nurse about any and all prescription and non-prescription medicines, vitamins, herbs, and supplements you are taking.

• Make a list of the name of each drug, the dose, how often you take it, who prescribed it, and the reason you take it.

• Be sure to include the things you may not think of as medicines. This includes aspirin, herbal and dietary supplements, vitamins, minerals, and all over-the-counter medicines.

Your doctor will tell you if you should stop taking any of these medicines before you start chemo. After your treatments start, check with your doctor before taking any new medicines or supplements and before stopping the ones you already take.

How will I know if the chemo is working?

Your cancer care team will measure how well your treatments are working by doing certain tests. This may include physical exams, blood tests, bone marrow biopsies, scans, and x-rays. Ask your doctor about the test results and what they show about your progress. You may have side effects, but these side effects do not tell you whether treatment is working.

How do I give my permission for this treatment?

You will be asked to give your written permission to get chemo based on your understanding of the drugs your doctor recommends. Know the answers to all of these questions before you sign the consent form.

• Which chemo drugs will I be given?

• How will the drugs be given to me?

• How often will I need to get chemo?

• How long will my treatments last?

• What side effects could I have from these drugs?

• How likely is this treatment to be successful?

The specifics of the consent form may vary from state to state, but the form usually states that your doctor has explained your condition to you, how the chemo will benefit you, the risks, and the other options available to you. Your signature on the form means that you have gotten this information and that you are willing to be treated with chemo. This process is called giving informed consent.

Go back to Understanding Chemotherapy: A Guide for Patients and Families.

Last Medical Review: 11/02/2009
Last Revised: 11/02/2009