Chemotherapy





Definition

Chemotherapy, sometimes referred to as "chemo," is the treatment of cancer with anticancer drugs.

Purpose

The main purpose of chemotherapy is to kill cancer cells. It usually is used to treat patients with cancer that has spread from the place in the body where it originated (metastasized). Chemotherapy destroys cancer cells anywhere in the body. It even kills cells that have broken off from the main tumor and traveled through the blood or lymph systems to other parts of the body.

Chemotherapy can cure some types of cancer. In some cases, it is used to slow the growth of cancer cells or to keep the cancer from spreading to other parts of the body. Chemotherapy may be given before surgery or radiation therapy to shrink the tumor (neoadjuvant therapy). When a cancer has been removed by surgery or treated with radiation therapy, chemotherapy may be used to keep the cancer from coming back (adjuvant therapy).

Once a remission is achieved, consolidation chemotherapy, also called intensification chemotherapy, is given to sustain a remission. Maintenance chemotherapy is chemotherapy given in lower doses as a treatment to prolong a remission in certain types of cancer. Chemotherapy also can ease the symptoms of cancer (palliative chemotherapy), helping some patients have a better quality of life.

Description

Chemotherapy for the treatment of cancer began in the 1940s with the use of nitrogen mustard. More than 100 chemotherapy drugs are now available to treat cancer, and many more are being tested for their ability to destroy cancer cells.

Most chemotherapy drugs interfere with the ability of cells to grow or multiply. Although these drugs affect all cells in the body, many useful treatments are most effective against rapidly growing cells. Cancer cells grow more quickly than most other body cells. Other cells that grow fast are cells of the bone marrow that produce blood cells, cells in the stomach and intestines, and cells of the hair follicles. Therefore, the most common side effects of chemotherapy are linked to the treatment's effects on other fast-growing cells.

Types of chemotherapy drugs

Chemotherapy drugs are classified according to how they work. The main types of chemotherapy drugs are:

  • Alkylating drugs—kill cancer cells by directly attacking DNA, the genetic material of the genes. Cyclophosphamide is an alkylating drug.
  • Antimetabolites—interfere with the production of DNA and keep cells from growing and multiplying. An example of an antimetabolite is 5-fluorouracil (5-FU).
  • Antitumor antibiotics—made from natural substances such as fungi in the soil. They interfere with important cell functions, including production of DNA and cell proteins. Doxorubicin and bleomycin belong to this group of chemotherapy drugs.
  • Plant alkaloids—prevent cells from dividing normally. Vinblastine and vincristine are plant alkaloids obtained from the periwinkle plant.
  • Steroid hormones—slow the growth of some cancers that depend on hormones. For example, tamoxifen is used to treat breast cancers whose growth depends on the hormone estrogen.
  • Topoisomerase inhibitors—interfere with the action of topoisomerase enzymes, the enzymes that control the part of DNA needed to multiply. Etoposide belongs to this group.

Biological therapy

Biological therapy, also called immunotherapy, consists of treatment with substances that boost the body's own immune system against cancer. The body usually produces these substances in small amounts to fight diseases. These substances can be made in the laboratory and given to patients to destroy cancer cells, change the way the body reacts to a tumor, or help the body repair or make new cells destroyed by chemotherapy.

Combination chemotherapy

Chemotherapy usually is given in addition to other cancer treatments, such as surgery and radiation therapy. When given with other treatments, it is called adjuvant chemotherapy. An oncologist decides on the specific chemotherapy drug or combination of drugs that will work best for each patient. The use of two or more drugs together—combination chemotherapy—often works better than using a single drug. Scientific studies of different drug combinations help doctors learn the combinations that work best for each type of cancer. For example, research in 2003 found that a combination of chemotherapy and gene therapy stopped breast cancer and its metastasis (spread to other organs or parts of the body).

Clinical trials

Some patients may be eligible to participate in clinical trials, research programs conducted with patients to evaluate a new drug, medical treatment, device, or combination of treatments. The purpose of clinical trials is to find new and improved methods of treating different diseases and special conditions. More information is available at the National Institutes of Health's clinical trials Web site, http://www.clinicaltrials.gov or by calling (888) FIND-NLM, (888) 346-3656 or (301) 594-5983. Another resource is the National Cancer Institute's Web site, http://www.cancer.gov/clinicaltrials.

Precautions

There are many different types of chemotherapy drugs. Oncologists, doctors who specialize in treating cancer, determine the drugs that are best suited for each patient. This decision is based on the type and severity of cancer, location of the cancer, patient's age and health, and other drugs the patient takes. Some patients should not be treated with certain chemotherapy drugs. Age and other conditions may affect the drugs selected for treatment. Heart disease, kidney disease, and diabetes are conditions that may limit the choice of treatment drugs. In 2003, research revealed that obesity appears to reduce the effectiveness of high-dose chemotherapy. Researchers said further study was needed to determine the best dosage for obese patients receiving therapy.

How chemotherapy is given

Chemotherapy is administered in different ways, depending on the drugs to be given and the type of cancer. Doctors determine the dose of chemotherapy drugs based on many factors, including the patient's height and weight.

Chemotherapy may be given by one or more of the following methods:

  • orally (by mouth)
  • injection
  • through a catheter or port
  • topically (via the skin)

Oral chemotherapy is given by mouth in the form of a pill, capsule, or liquid. This is the easiest method and can usually be done at home.

Intravenous (IV) chemotherapy is injected into a vein. A small needle is inserted into a vein on the hand or lower arm. The needle usually is attached to a small tube called a catheter, which delivers the drug to the needle from an IV bag or bottle.

Intramuscular (IM) chemotherapy is injected into a muscle. Chemotherapy given by intramuscular injection is absorbed into the blood more slowly than IV chemotherapy. Because of this, the effects of IM chemotherapy may last longer than chemotherapy given intravenously. Chemotherapy also may be injected subcutaneously (SQ or SC), which means under the skin. Injection of chemotherapy directly into the cancer is called intralesional (IL) injection.

Chemotherapy also may be given by a catheter or port permanently inserted into a central vein or body cavity. A port is a small reservoir or container that is placed in a vein or under the skin in the area where the drug will be given. These methods eliminate the need for repeated injections and may allow patients to spend less time in the hospital while receiving chemotherapy. A common location for a permanent catheter is the external jugular vein in the neck.

Intraperitoneal (IP) chemotherapy is administered into the abdominal cavity through a catheter or port. Chemotherapy given by catheter or port into the spinal fluid is called intrathecal (IT) administration. Catheters and ports also may be placed in the chest cavity, abdomen, bladder, or pelvis (intracavitary or IC catheter), depending on the location of the cancer to be treated.

Topical chemotherapy is given as a cream or ointment applied on the surface of the skin. This method is more common in treatment of certain types of skin cancers.

Treatment location and schedule

Patients may take chemotherapy at home, in the doctor's office, or as an inpatient or outpatient at the hospital. The choice of where to have chemotherapy depends on the drugs, delivery method, and sometimes the patient's and family's personal preferences. Most patients receive chemotherapy as an outpatient. Some patients stay in the hospital when first beginning chemotherapy, so their doctor can check for any side effects and change the dose if needed.

Frequency and length of chemotherapy treatment depends on the form of cancer, types of drugs, how the patient responds to the treatment, and the patient's health and ability to tolerate the drugs. Chemotherapy administration may take only a few minutes or as long as several hours. Chemotherapy may be given daily, weekly, or monthly. A rest period may follow a course of treatment before the next course begins, allowing new cells to grow and the patient to recover and regain strength. In combination chemotherapy, more than one drug may be given at a time, or the drugs may be given alternately, one following the other.

Maintaining the prescribed treatment schedule is essential to ensuring that the drugs work properly. The doctor should be contacted as soon as possible if a treatment session is missed, or a dose of the drug is skipped, for whatever reasons. Sometimes the doctor may need to delay a treatment based on the results of certain blood tests. Specific instructions will be provided if a treatment delay becomes necessary.

Preparation

TESTS A number of medical tests are done before chemotherapy is started. The results of x rays , other imaging tests, and tumor samples taken during biopsy or surgery will help the oncologist determine how much the cancer has spread.

Blood tests give the doctor important information about the function of the blood cells and levels of chemicals in the blood. A complete blood count (CBC) is commonly done before and regularly during treatment. The CBC shows the numbers of white blood cells, red blood cells, and platelets in the blood. Because chemotherapy affects the bone marrow, where blood cells are made, levels of these cells often drop during chemotherapy. The white blood cells and platelets are most likely to be affected by chemotherapy. A drop in the white blood cell count means the immune system cannot function properly. Low levels of platelets can cause a patient to bleed easily from a cut or other wound. A low red blood cell count can lead to anemia (deficiency of red blood cells) and fatigue.

INFORMED CONSENT Informed consent is an educational process between health care providers, patients, and/or their legal guardians. Before any procedure is performed or any form of medical care is provided, the patient and parents (if the patient is under age 18), are asked to sign a consent form, which provides permission for the child to receive chemotherapy treatment. The health care provider will review the informed consent form with the parents before they are asked to sign it. Before signing the form, the patient and parents should understand the nature and purpose of the treatment, its risks and benefits, and alternatives, including the option of not proceeding with the treatment. During the discussion about treatment, the health care providers are available to answer the patient's and parents' questions about the consent form or course of treatment.

PREPARING FOR THE TREATMENT When a chemotherapy treatment takes a long time, the patient may prepare for it by wearing comfortable clothes. Packing a book, favorite game, or an audiotape may help pass the time and ease the stress of receiving chemotherapy.

Usually parents stay with their child during the treatment. It is necessary to drive the child home (even if he or she is old enough to drive), since the medications taken to control nausea and the chemotherapy treatment itself can cause drowsiness.

ANTI-EMETIC DRUGS Sometimes, patients taking chemotherapy drugs known to cause nausea are given medications called anti-emetics before chemotherapy is administered. Anti-emetic drugs help to lessen feelings of nausea. Two anti-nausea medications that may be used are Kytril and Zofran. To decrease nausea from occurring just after a chemotherapy session, the child should not eat for about two hours before the treatment appointment.

Research published in 2003 revealed that taking melatonin, a natural hormone substance, may help improve chemotherapy's effectiveness and reduce the toxic effects of the drugs.

Aftercare

Tips for helping to control side effects after chemotherapy include:

  • following any instructions given by the doctor or nurse
  • taking all prescribed medications
  • eating small amounts of bland foods
  • maintaining good nutrition by getting enough calories, including protein in the diet, and taking a daily multivitamin (as recommended by the child's physician)
  • drinking at least eight cups of fluids per day
  • getting plenty of rest
  • exercising regularly

Some patients find it helpful to breathe fresh air or get mild exercise , such as taking a walk.

Side effects and their severity are not indicators of how well the chemotherapy is working, since they vary greatly among patients and from drug to drug. Tests and exams can help determine the effectiveness of the chemotherapy.

Risks

Chemotherapy drugs are toxic to normal cells as well as cancer cells. A dose that will destroy cancer cells will probably cause damage to some normal cells. Doctors adjust doses to do the least amount of harm possible to normal cells. Side effects are temporary, and damaged non-cancerous cells will be replaced with healthy cells.

Some patients feel few or no side effects, and others may have more serious side effects. In some cases, a dose adjustment is all that is needed to reduce or stop a side effect. The types and severity of side effects depend on the chemotherapy drugs, dose, length of therapy, the body's reaction to the drug, and the child's overall health at the start of chemotherapy.

Some chemotherapy drugs have more side effects than others. Among the most common side effects are:

  • fatigue
  • nausea and vomiting
  • loss of appetite
  • diarrhea
  • hair loss
  • anemia
  • infection
  • easy bleeding or bruising
  • sores in the mouth and throat
  • neuropathy and other damage to the nervous system
  • kidney damage

Fatigue (feeling tired and lacking energy) is the most common side effect of cancer and chemotherapy medications. Fatigue gradually goes away as the cancer responds to treatment. To help a child cope with fatigue, parents should plan rest periods, provide nutritious meals to maintain energy and meet caloric needs, limit caffeine , and encourage exercise and activity.

Nausea and vomiting are common, but can usually be controlled by taking anti-nausea drugs; consuming adequate fluids; drinking fluids at least one hour before or after a meal; eating and drinking slowly, chewing food completely; eating smaller meals throughout the day; choosing high-carbohydrate, low-fat foods; and avoiding sweet, fried, or spicy foods. When vomiting episodes stop, the child may feel better after eating easy-to-digest and bland foods such as clear liquids, crackers, gelatin, and plain toast.

Loss of appetite may be due to nausea, changes in taste and smell, or the stress of undergoing cancer treatment. To help maintain the child's appetite, meals and snacks should be small rather than large. Food should be served when the child is hungry, and he or she should be offered favorite foods. It is recommended that children help select and prepare foods. Calories may be boosted by offering high-calorie and high-protein snacks and foods. Sometimes a feeding tube may be needed to maintain a child's weight or for children who cannot eat or drink.

If the child has diarrhea, high-fiber and high-fat foods, gassy foods, and carbonated beverages should be avoided. It is important for the child to continue drinking fluids throughout the day to avoid dehydration from diarrhea or vomiting.

Some chemotherapy drugs cause hair loss, but it is almost always temporary. The doctor can advise the parents and patients if hair loss is expected with the type of chemotherapy drug to be given. When hair loss occurs, it may begin after a few treatments, or several weeks after the first treatment. To care for the scalp and hair during chemotherapy, the child should use a mild shampoo and soft brush, and low heat for hair drying. The head should be protected from heat and sun with a hat or scarf. If desired, a wig or hair piece may be worn.

Low blood cell counts caused by the effect of chemotherapy on the bone marrow can lead to anemia, infections, and easy bleeding and bruising. Patients with anemia have too few red blood cells to deliver oxygen and nutrients to the body's tissues. Anemic patients feel tired and weak, are short of breath, and may have a rapid heartbeat. If red blood cell levels fall too low, a blood transfusion may be given.

Patients receiving chemotherapy are more likely to acquire infections because their infection-fighting white blood cells are reduced. It is important to take measures to avoid infections. When the white blood cell count drops too low, the doctor may prescribe medications called colony stimulating factors, which help white blood cells grow. Neupogen and Leukine are two colony stimulants that help fight infection. To reduce the risk of infection, thorough and frequent hand washing and safe food preparation are essential.

Platelets are blood cells that make the blood clot. When patients do not have enough platelets, they may bleed or bruise easily, even from small injuries. Patients with low blood platelets should take precautions to avoid injuries. Medicines such as aspirin and other pain relievers can affect platelets and slow down the clotting process.

Chemotherapy can cause irritation and dryness in the mouth and throat. Painful sores may form that can bleed and become infected. To help avoid mouth sores and irritation, the child should have a dental cleaning before chemotherapy begins, take care of the teeth and gums by brushing and flossing after every meal with a soft brush, rinse with a solution of baking soda and water, and avoid mouth washes or rinses that contain salt or alcohol. After use, the toothbrush should be rinsed thoroughly and stored in a dry place.

To help the child cope with a dry mouth, parents should encourage him or her to drink plenty of liquids. Popsicles or lollipops offer relief. Soft foods may be prepared, and dry foods may be moistened with sauce, butter, or gravy.

Tiredness, confusion, and depression can occur from chemotherapy's effect on certain central nervous system functions. The doctor should be notified if these symptoms occur.

Tests will be performed to monitor the effects of chemotherapy medications on the patient's kidneys and liver. Monitoring kidney and liver function helps to avoid potential damage or complications.

Normal results

The main goal of chemotherapy is to cure cancer. In fact, many cancers are cured by chemotherapy. Chemotherapy may be used in combination with surgery to keep a cancer from spreading to other parts of the body. Some widespread, fast-growing cancers are more difficult to treat. In these cases, chemotherapy may slow the growth of cancer cells.

The results of medical tests provide information so doctors can tell if the chemotherapy is working. Physical examination, blood tests, and x rays are used to check the effects of treatment on the cancer.

The possible outcomes of chemotherapy are:

  • Complete remission or response. The cancer completely disappears; there is no evidence of disease. The course of chemotherapy is completed and the patient is tested regularly for a recurrence.
  • Partial remission or response. The cancer shrinks in size but does not disappear. The same chemotherapy may be continued or a different combination of drugs may be given.
  • Stabilization. The cancer does not grow or shrink. Other therapy options may be explored. A tumor may stay stabilized for many years.
  • Progression. The cancer continues to grow. Other therapy options may be explored.
  • A secondary malignancy may develop from the one being treated, and that second cancer may need additional chemotherapy or other treatment.

Parental concerns

Some important questions parents can ask about their child's course of chemotherapy include:

  • What specific drugs will be given?
  • How will the drugs be administered, and where will they be given?
  • What are the potential benefits and risks of these drugs?
  • What are some other possible treatments for the child's type of cancer?
  • What is the standard care for the child's type of cancer?
  • Are there any applicable clinical trials currently enrolling children?
  • How many treatments will be needed? How long will they last?
  • What are the potential side effects? When might they occur? How can they be treated or relieved? How serious are they likely to be? What side effects should be reported to the child's doctor?
  • Can the child take other prescription or over-the-counter medications while receiving chemotherapy?
  • What activities should be restricted or limited during the course of treatment?
  • What is the long-term effect of chemotherapy?

Most school-age children can continue to go to school while receiving chemotherapy. However, the school schedule may need adjustment according to how the child feels and what side effects he or she experiences. During the cold and flu season, it may be best to keep the child home to prevent infection. If possible, treatments should be scheduled on a day when there is no school the next day, to provide time to recover.

To reduce the child's exposure to colds and illnesses and to help the child avoid infection:

  • The child should avoid crowded areas, such as shopping malls.
  • The child and entire family should be encouraged to wash hands frequently.
  • People who are sick should be avoided, and they should be asked to refrain from visiting until they are healthy.
  • The child should stay away from children who have recently received live virus vaccines such as chicken pox and oral polio since they may be contagious to people with a low blood cell count.
  • Contact with animal litter boxes and waste, bird cages, and fish should be prevented.
  • Contact with standing water, such as bird baths, flower vases, or humidifiers, should be prevented.
  • Food must be safely prepared and cooked thoroughly to avoid food-borne illnesses.
  • Parents should check with the child's doctor before scheduling immunizations, flu, or pneumonia vaccines.

Aspirin and products containing aspirin should be avoided, as they can affect platelet counts. Parents should check with the child's doctor before giving any vitamins , herbal supplements, and any over-the-counter medications.

The child's doctor should provide specific activity guidelines, including recommendations regarding the child's sports participation. Contact sports may be discouraged to reduce the risk of injury.

Treatment and care for a child with cancer can be costly, and some health insurance plans may not cover all expenses associated with a child's hospitalization or treatment. Help is available to cover medical expenses. The parents can discuss financial aid with the hospital. Some organizations provide financial assistance to children in need of chemotherapy or other cancer treatments.

Caring for a child with cancer is demanding. Support groups are available to help parents and caregivers cope with the challenges of providing care for children with special medical needs. It is important for parents to take care of themselves, too, by eating properly,

exercising regularly, taking care of personal hygiene, keeping in contact with friends and family members for support, and managing stress by practicing relaxation techniques.

When to call the doctor

If a child has any of these symptoms, the parent or caregiver should call the child's doctor right away, as they could indicate an infection, blood clotting problem, or effect on the central nervous system:

  • abdominal pain, vomiting, or diarrhea that awakens the child during the night
  • persistent or severe abdominal pain, vomiting, or diarrhea
  • unexplained weight loss
  • fever
  • chills or sweating
  • frequent urgency to urinate, burning during urination, or change in color of urine
  • rectal bleeding, or black or bloody bowel movements
  • severe cough or sore throat
  • redness, swelling, or tenderness, especially around a wound or sore
  • earaches, headaches, or stiff neck
  • mouth sores, or blisters on the lips or skin
  • sinus pain or pressure
  • headaches
  • changes in vision
  • unexplained bleeding or bruising
  • red spots under the skin
  • confusion
  • persistent depressed mood
  • worsening overall health

KEY TERMS

Adjuvant therapy —A treatment that is intended to aid primary treatment.

Alkaloid —A type of chemical commonly found in plants and often having medicinal properties.

Alkylating agent —A chemical that alters the composition of the genetic material of rapidly dividing cells, such as cancer cells, causing selective cell death; used as a chemotherapeutic agent.

Alopecia —The loss of hair, or baldness.

Anti-emetic —A preparation or medication that relieves nausea and vomiting. Cola syrup, ginger, and motion sickness medications are examples of antiemetics.

Antimetabolite —A drug or other substance that interferes with a cell's growth or ability to multiply.

Benign —In medical usage, benign is the opposite of malignant. It describes an abnormal growth that is stable, treatable, and generally not life-threatening.

Blood cell count —The number of red blood cells, white blood cells, and platelets in a sample of blood. Also called a complete blood count (CBC).

Bone marrow —The spongy tissue inside the large bones in the body that is responsible for making the red blood cells, most white blood cells, and platelets.

Catheter —A thin, hollow tube inserted into the body at specific points in order to inject or withdraw fluids from the body.

Chest x ray —Brief exposure of the chest to radiation to produce an image of the chest and its internal structures.

Infusion —Introduction of a substance directly into a vein or tissue by gravity flow.

Lymph nodes —Small, bean-shaped collections of tissue located throughout the lymphatic system. They produce cells and proteins that fight infection and filter lymph. Nodes are sometimes called lymph glands.

Malignant —Cells that have been altered such that they have lost normal control mechanisms and are capable of local invasion and spread to other areas of the body. Often used to describe a cancer.

Metastatic —The term used to describe a secondary cancer, or one that has spread from one area of the body to another.

Platelet —A cell-like particle in the blood that plays an important role in blood clotting. Platelets are activated when an injury causes a blood vessel to break. They change shape from round to spiny, "sticking" to the broken vessel wall and to each other to begin the clotting process. In addition to physically plugging breaks in blood vessel walls, platelets also release chemicals that promote clotting.

Radiation therapy —A cancer treatment that uses high-energy rays or particles to kill or weaken cancer cells. Radiation may be delivered externally or internally via surgically implanted pellets. Also called radiotherapy.

Red blood cells —Cells that carry hemoglobin (the molecule that transports oxygen) and help remove wastes from tissues throughout the body.

Remission —A disappearance of a disease and its symptoms. Complete remission means that all disease is gone. Partial remission means that the disease is significantly improved, but residual traces of the disease are still present. A remission may be due to treatment or may be spontaneous.

Tumor —A growth of tissue resulting from the uncontrolled proliferation of cells.

White blood cells —A group of several cell types that occur in the bloodstream and are essential for a properly functioning immune system; they fight infection.

Resources

BOOKS

Fischer, David A., et al. The Cancer Chemotherapy Handbook. London: C.V. Mosby, 2003.

McKay, Judith, and Nancee Hirano. The Chemotherapy and Radiation Therapy Survivor's Guide, 2nd ed. Oakland, CA: New Harbinger Publications, 1998.

Skeel, Roland T. K. Handbook of Cancer Chemotherapy, 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2003.

PERIODICALS

"Chemotherapy and You: A Guide to Self-Help During Cancer Treatment." National Institutes of Health, National Cancer Institute. NIH Publication No. 03-1136, 2003.

"Gene Therapy and Chemotherapy Combine to Stop Breast Cancer and its Metastasis." Gene Therapy Weekly (Oct. 30, 2003): 2.

"Melatonin Improves the Efficacy of Chemotherapy and Quality of Life" Biotech Week (Sept. 10, 2003): 394.

"Obesity May Reduce Efficacy of High-Dose Chemotherapy." Health Medicine Week (Aug. 11, 2003): 385.

ORGANIZATIONS

American Cancer Society. 1599 Clifton Rd., NE, Atlanta, GA 30329-4251. (800) 227-2345 or (404) 320-3333. Web site:http://www.cancer.org.

Cancercare. (800) 813-4673. Web site: http://www.cancercare.org.

National Cancer Institute. U.S. National Institutes of Health. Building 31, Room 10A31, 31 Center Drive, MSC 2580, Bethesda, MD 20892-2580. (800) 422-6237. Web site: http://www.cancer.gov.

WEB SITES

CancerAnswers. Available online at: http://www.canceranswers.com.

Chemocare.com. Available online at: http://www.chemocare.com.

OncoLink. University of Pennsylvania Cancer Center. Available online at: http://www.oncolink.upenn.edu.

Planet Cancer. Available online at: http://www.planetcancer.org.

Toni Rizzo Teresa G. Odle Angela M. Costello



User Contributions:

Anne Provost
Report this comment as inappropriate
Feb 15, 2008 @ 2:14 pm
My son has oliogodendrom brain cancer...I live in Canada....Is the new chemo that can be in smaller doses year round available in Canada and FDA approved...Also what are the results of this study?.....Anne

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