Cancer Treatment FAQ

Cancer Treatment Side Effects

How is cancer treated?

Surgery, chemotherapy, and radiation are the 3 main types of cancer treatment. A person with cancer may have any or all of these treatments. In choosing a treatment plan, the most important factors are generally the type of cancer and the stage (amount) of the cancer. Other factors to consider include the person’s overall health, the likely side effects of the treatment, and the probability of curing the cancer, controlling it to extend life, or easing symptoms.


Surgery is often the first treatment used if the cancer can be taken out of the body. Sometimes only part of the cancer can be removed. And, sometimes there may be risks to doing surgery for a cancer diagnosis. Radiation or chemotherapy might be used to shrink the cancer before or after surgery.


Doctors use chemotherapy or “chemo” drugs to kill cancer cells. Usually, the drugs are given intravenously (IV or into a vein) or taken as a pill by mouth. Chemo drugs travel throughout the body in the bloodstream. They can reach cancer cells that may have spread away from the tumor.

Radiation therapy

Radiation therapy is treatment with high energy rays (such as x-rays) to kill or shrink cancer cells. The radiation may come from outside the body, called external radiation, or from radioactive materials placed right into the tumor (internal or implant radiation). Getting external radiation is a lot like getting an x-ray.

Other types of cancer treatment

Other kinds of treatment you might hear about include targeted therapy, stem cell or bone marrow transplant, and immunotherapy Hormone therapy is another type of treatment that’s sometimes used to treat certain kinds of cancer.

What Causes Side Effects?

Cancer cells tend to grow fast, and chemo drugs kill fast-growing cells. But because these drugs travel throughout the body, they can affect normal, healthy cells that are fast-growing, too. Damage to healthy
cells causes side effects. Side effects are not always as bad as you might expect, but many people worry
about this part of cancer treatment.
The normal cells most likely to be damaged by chemo are :

  • Blood-forming cells in the bone marrow
  • Hair follicles
  • Cells in the mouth
  • digestive tract
  • reproductive system

Some chemo drugs can damage cells in the heart, kidneys, bladder, lungs, and nervous system. Sometimes, you can take medicines with the chemo to help protect your body’s normal cells. There are also treatments to help relieve side effects.

Doctors try to give chemo at levels high enough to treat cancer, while keeping side effects at a minimum. They also try to avoid using multiple drugs that have similar side effects.

What do I need to know about side effects?

While side effects can be unpleasant, they must be weighed against the need to kill the cancer cells.

Every person doesn’t get every side effect, and some people get few, if any. The severity of side effects (how bad they are) varies greatly from person to person. Be sure to talk to your cancer care team about which side effects are most common with your chemo, how long they might last, how bad they might be, and when you should call the doctor’s office about them.

Your doctor may give you medicines to help prevent certain side effects before they happen. Some chemo drugs cause long-term side effects, like heart or nerve damage or fertility problems. Still, many people have no long-term problems from chemo. Ask your doctor if the chemo drugs you’re getting have long-term effects.

Be sure to talk to your cancer care team about which side effects are most common with your chemo, how long they might last, how bad they might be, and when you should call the doctor’s office about them.

How Long Do Side Effects Last?

Many side effects go away fairly quickly aer treatment ends, but some may take months or even years to completely go away. The time it takes to get over some side effects and get your energy back varies from person to person. It depends on many factors, including your overall health and the drugs you were given.

Many side effects go away fairly quickly, but some might take months or even years to go away completely. Sometimes the side effects can last a lifetime, such as when chemo causes long-term damage to the heart, lungs, kidneys, or reproductive organs. Certain types of chemo sometimes cause delayed effects, such as a second cancer that may show up many years later.

People oen become discouraged about how long their treatment lasts or the side effects they have. If you feel this way, talk to your cancer care team. You may be able to change your medicine or treatment schedule. They also may be able to suggest ways to reduce any pain and discomfort you have.

What are common side effects?

Most people worry about whether they’ll have side effects from chemo, and, if so, what they’ll be like. Here are some of the more common side effects caused by chemotherapy:

  • Fatigue
  • Hair loss
  • Easy bruising and bleeding
  • Infection
  • Anemia (low red blood cell counts)
  • Nausea and vomiting
  • Appetite changes
  • Constipation
  • Diarrhea
  • Mouth, tongue, and throat problems such as sores and pain with swallowing
  • Nerve and muscle problems such as numbness, tingling, and pain
  • Skin and nail changes such as dry skin and color change

Cancer Treatment Drug Interactions and Side Effects

When looking at how best to combine chemo drugs, doctors must look at interactions between chemo drugs and other medicines the person is taking, including over-the-counter medicines, vitamins, and supplements. These interactions may make side effects worse and affect how well chemo drugs work. It’s important that you tell your doctor about all medicines, including over-the counter medicines, vitamins, herbal or dietary supplements you are taking– even if you only take them “as needed.”

For instance, platelets help blood clot and prevent bleeding. Many chemo drugs lower the number of platelets for a time. Taking aspirin or other related drugs can also weaken blood platelets. This isn’t a problem for healthy people with normal platelet counts. But if a person has low platelet counts from chemo, this combination might put them at risk of a serious bleeding problem. Your doctor can talk with you about the safety of using other medicines, vitamins, and supplements while you are being treated for cancer.

How Vitamins Affect Cancer Treatment Drugs

Many people want to take an active role in improving their overall health. They want to help their body’s natural defenses fight the cancer and speed up their recovery from chemo. Because most people think of vitamins as a safe way to improve health, it’s not surprising that many people with cancer take high doses of one or more vitamins. But some vitamins might make chemo less effective. Certain vitamins, such as A, E, and C act as antioxidants. This means that they can prevent formation of ions (free radicals) that damage DNA. This damage is thought to have an important role in causing cancer.

Some chemotherapy drugs (as well as radiation treatments) work by producing these same types of free radical ions. These ions damage the DNA of cancer cells so the cells are unable to grow and reproduce. Some scientists believe that taking high doses of antioxidants during treatment may make chemo or radiation less effective.

  • Urine and bladder changes and kidney problems
  • Weight changes
  • Chemo brain, which can affect concentration and focus
  • Mood changes
  • Changes in libido and sexual function
  • Fertility problems

Few studies have been done to fully test this theory. But until more is known about the effects of vitamins on chemo, keep these points in mind: When to call your cancer care team about side effects from chemotherapy

While you’re getting chemotherapy, you’ll probably notice every physical change and imbalance. Do not take any physical symptoms you have lightly.

Some side effects are short-lived and minor, but others may be a sign of serious problems. You should not be the judge. Make sure you know how to reach someone on your team any time, including aer hours,
weekends, and holidays.

Contact your cancer care team right away if you have any of the following symptoms during chemo treatment:

  1. Ask your cancer care team if there are any other problems they should know about right away.
  2. If your doctor has not told you to take vitamins, it’s best not to take any.
  3. A simple multivitamin is probably OK for people who want to take a vitamin supplement, but always check with your doctor first.
  4. It’s safest to avoid taking high doses of antioxidant vitamins or supplements during cancer treatment.
  5. Ask your doctors if and when it might be OK to start such vitamins per treatment.
  6. If you’re concerned about nutrition, you can usually get plenty of vitamins by eating a well-balanced diet. See Nutrition for People With Cancer to learn more about nutrition during and aer cancer
  7. A fever of 100.5°F or greater (taken by mouth)
  8. Bleeding or unexplained bruising
  9. A rash or allergic reaction, such as swelling of the mouth or throat, severe itching, trouble swallowing Intense chills
  10. Pain or soreness at the chemo injection site or catheter site
  11. Unusual pain, including intense headaches
  12. Shortness of breath or trouble breathing (If you’re having trouble breathing call 911 first.)
  13. Long-lasting diarrhea or vomiting
  14. Bloody stool or blood in your urine

How Cancer Treatment Drugs Work

More than 100 chemotherapy or chemo drugs are used to treat cancer – either alone or in combination with other drugs or treatments. These drugs are very different in their chemical composition, how they are taken, their usefulness in treating specific forms of cancer, and their side effects.

  1. Chemotherapy works with the cell cycle

2. Chemotherapy drugs target cells at different phases of the process of forming new cells, called the cell
cycle. Understanding how these drugs work helps doctors predict which drugs are likely to work well
together. Doctors can also plan how oen doses of each drug should be given based on the timing of the
cell phases.

3. Cancer cells tend to form new cells more quickly than normal cells and this makes them a better target for
chemotherapy drugs. However, chemo drugs can’t tell the difference between healthy cells and cancer
cells. This means normal cells are damaged along with the cancer cells, and this causes side effects. Each
time chemo is given, it means trying to find a balance between killing the cancer cells (in order to cure or
control the disease) and sparing the normal cells (to lessen side effects).

Types of Cancer Treatment Drugs

Chemo drugs can be grouped by how they work, their chemical structure, and their relationships to other drugs. Some drugs work in more than one way, and may belong to more than one group. (Note: not all chemotherapy drugs are listed here.)

Knowing how the drug works is important in predicting side effects from it. This helps doctors decide which drugs are likely to work well together. If more than one drug will be used, this information also helps them plan exactly when each of the drugs should be given (in which order and how oen).

Alkylating Agents

Alkylating agents keep the cell from reproducing by damaging its DNA. These drugs work in all phases of the cell cycle and are used to treat many different cancers, including cancers of the lung, breast, and ovary
as well as leukemia, lymphoma, Hodgkin disease, multiple myeloma, and sarcoma.

Because these drugs damage DNA, they can affect the cells of the bone marrow which make new blood cells. In rare cases, this can lead to leukemia. The risk of leukemia from alkylating agents is “dosedependent,” meaning that the risk is small with lower doses, but goes up as the total amount of the drug used gets higher. The risk of leukemia aer getting alkylating agents is highest about 5 to 10 years aer treatment.

Examples of alkylating agents include:


Antimetabolites interfere with DNA and RNA growth by substituting for the normal building blocks of RNA and DNA. These agents damage cells during the phase when the cell’s chromosomes are being copied.
They are commonly used to treat leukemias, cancers of the breast, ovary, and the intestinal tract, as well as other types of cancer.

Examples of antimetabolites include:

  • Altretamine
  • Busulfan
  • Carboplatin
  • Carmustine
  • Chlorambucil
  • Cisplatin
  • Cyclophosphamide
  • Dacarbazine
  • Lomustine
  • Melphalan
  • Oxaliplatin
  • Temozolomide
  • Thiotepa
  • 5-fluorouracil (5-FU)
  • 6-mercaptopurine (6-MP)
  • Capecitabine (Xeloda®)
  • Cytarabine (Ara-C®)
  • Floxuridine
  • Fludarabine
  • Anti-tumor antibiotics

These drugs are not like the antibiotics used to treat infections. They work by changing the DNA inside cancer cells to keep them from growing and multiplying.


Anthracyclines are anti-tumor antibiotics that interfere with enzymes involved in copying DNA during the cell cycle. (Enzymes are proteins that start, help, or speed up the rate of chemical reactions in cells.) They are widely used for a variety of cancers.

Examples of anthracyclines include:
A major concern when giving these drugs is that they can permanently damage the heart if given in high doses. For this reason, lifetime dose limits are oen placed on these drugs.

Anti-tumor antibiotics that are not anthracyclines include:

Topoisomerase inhibitors
These drugs interfere with enzymes called topoisomerases, which help separate the strands of DNA so they
can be copied. (Enzymes are proteins that cause chemical reactions in living cells.) Topoisomerase
inhibitors are used to treat certain leukemias, as well as lung, ovarian, gastrointestinal, and other cancers.

Topoisomerase inhibitors are grouped according to which type of enzyme they affect:

Topoisomerase I inhibitors include:

  • Gemcitabine (Gemzar®)
  • Hydroxyurea
  • Methotrexate
  • Pemetrexed (Alimta®)
  • Daunorubicin
  • Doxorubicin (Adriamycin®)
  • Epirubicin
  • Idarubicin
  • Actinomycin-D
  • Bleomycin
  • Mitomycin-C
  • Mitoxantrone

Mitotic inhibitors

Mitotic inhibitors are compounds derived from natural products, such as plants. They work by stopping cells from dividing to form new cells but can damage cells in all phases by keeping enzymes from making proteins needed for cell reproduction.

Examples of mitotic inhibitors include:

They are used to treat many different types of cancer including breast, lung, myelomas, lymphomas, and leukemias. These drugs may cause nerve damage, which can limit the amount that can be given.


Corticosteroids, oen simply called steroids, are natural hormones and hormone-like drugs that are useful in the treatment of many types of cancer, as well as other illnesses. When these drugs are used as part of cancer treatment, they are considered cancer treatment drugs.

Examples of corticosteroids include:

  • Topotecan
  • Irinotecan (CPT-11).
  • Etoposide (VP-16)
  • Teniposide.
  • Mitoxantrone (also acts as an anti-tumor antibiotic)
  • Docetaxel
  • Estramustine
  • Ixabepilone
  • Paclitaxel
  • Vinblastine
  • Vincristine
  • Vinorelbine

Steroids are also commonly used to help prevent nausea and vomiting caused by chemo. They are used before chemo to help prevent severe allergic reactions, too.

Other cancer treatment drugs

Some chemotherapy drugs act in slightly different ways and do not fit well into any of the other categories. Examples include drugs like L-asparaginase, which is an enzyme, and the proteosome inhibitor bortezomib
(Velcade ).

Other types of drugs used to treat cancer

Other drugs and biological treatments are used to treat cancer, but aren’t considered chemotherapy. They often have less side effects than chemotherapy. Many are used along with chemo.

Targeted therapies

Targeted therapies attack cancer cells more specifically than traditional chemotherapy drugs. These drugs can be used as part of the main treatment, or they may be used aer treatment to keep the cancer under
control or keep it from coming back.

Differentiating agents

These drugs act on the cancer cells to make them mature into normal cells. Examples include the retinoids, tretinoin (ATRA or Atralin ) and bexarotene (Targretin ), as well as arsenic trioxide (Arsenox ).

Hormone therapy

Drugs in this category are sex hormones, or hormone-like drugs, that are used to slow the growth of breast, prostate, and endometrial (uterine) cancers, which normally grow in response to natural sex hormones in
the body. They work by making the cancer cells unable to use the hormone they need to grow, or by preventing the body from making the hormone.

Source American Cancer Society for more information visit The American Cancer Society medical and editorial content team website (/cancer/acs-medical-content-and-news-staff.html). American Cancer Society’s team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

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