Side effects of chemotherapy

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Chemotherapy drugs kill cancer cells, but they can also damage normal cells. Damage to normal cells causes side effects. Chemotherapy drugs affect cells that are actively growing and dividing. This includes cancer cells, but it also includes blood cells in the bone marrow, cells lining the mouth, and gastrointestinal (GI) tract and hair follicle cells.

Side effects of chemotherapy will depend mainly on the type of drug, the dose, how it's given and your overall health. Side effects can happen with any type of treatment, but not everyone has them or experiences them in the same way. If you develop side effects, they can happen any time during, immediately after, or a few days or weeks after chemotherapy. Sometimes late side effects develop months or years after chemotherapy. Most side effects go away on their own or can be treated. But sometimes, side effects last longer or become permanent.

Many types of chemotherapy given today are easier to tolerate than they were in the past. Supportive drugs are given to protect certain cells or organs. These lessen the harmful side effects of some chemotherapy drugs. Find out more about supportive drugs.

Tell your healthcare team how you feel and if you think you have side effects from chemotherapy. Your team is there to help. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

The following are some of the side effects that people experience while having chemotherapy.

Low blood cell counts

Chemotherapy can reduce the number of blood cells made in the bone marrow. This can lead to low blood cell counts, which are the most common side effect of chemotherapy. There are different types of low blood cell counts.

Low blood cell counts are a serious side effect of chemotherapy. Your blood will be tested regularly during chemotherapy treatment to check your blood cell counts. If your blood counts are too low, delaying your chemotherapy treatment for a few days can allow them to recover.

Find out more about low blood cell counts.

Fatigue

Fatigue is a general lack of energy, tiredness or exhaustion. Most people have fatigue during cancer treatment, including chemotherapy. It is different from the tiredness a person usually feels at the end of the day.

Chemotherapy drugs can cause fatigue as a result of anemia. Fatigue may also be related to toxic substances that are made in the body when cancer cells break down and die. Fatigue is often worse when you are having chemoradiation, or if you have other treatments after you finish chemotherapy.

You may feel fatigue after having chemotherapy, but it usually improves in a few days as your body starts to recover. For some people, fatigue lasts a long time after chemotherapy is finished.

Tell your healthcare team if fatigue is severe or if you are having problems taking care of yourself. They may reduce the dose of chemotherapy to help with fatigue.

Find out more about fatigue.

Nausea and vomiting

Nausea is feeling sick to your stomach. Vomiting is throwing up. You may feel sick or throw up a few hours after treatment.

Nausea and vomiting usually lasts about 24 hours after chemotherapy. Delayed nausea and vomiting happens more than 24 hours later. Anticipatory nausea or vomiting may happen before chemotherapy is given, especially if you have had nausea and vomiting from chemotherapy before.

Some chemotherapy drugs are more likely to cause nausea and vomiting than others. Some chemotherapy drugs may not cause these side effects at all. You are more likely to experience nausea and vomiting during combination chemotherapy or when high doses of chemotherapy drugs are given.

Before starting chemotherapy, your healthcare team may give you antinausea drugs by intravenous (IV) to help prevent nausea and vomiting with chemotherapy drugs that are most likely to cause nausea and vomiting.

You may also be given antinausea drugs to take at home. These are usually pills (tablets or capsules). Take them when your healthcare team tells you to. Don't wait until you are very sick to take them, as you may vomit the drug and then it won't help.

Call your healthcare team if you have severe nausea and vomiting even after taking the antinausea drugs. You may need to be given the antinausea drugs along with fluids through a needle into a vein (intravenously, or by IV).

Find out more about nausea and vomiting.

Loss of appetite

Many people who are having chemotherapy treatments lose their appetite. This can be caused by nausea and vomiting, fatigue or a buildup of waste products as cancer cells die. Some chemotherapy drugs can temporarily change taste and smell, which can make food less appetizing. You may not feel like eating at all, even though you know you should. This can lead to malnutrition and weight loss. Eating well during and after chemotherapy is important to help you recover from treatment.

Find out more about loss of appetite.

Hair loss

Chemotherapy damages hair follicles because the drugs affect cells that are growing quickly. Not all chemotherapy drugs cause hair loss, but there are some that do.

You may begin to lose your hair within 2 to 3 weeks after chemotherapy starts. How much hair you lose and how long you experience hair loss for depends on the type and dose of the chemotherapy drugs you are given and how your body reacts.

Hair loss can happen on any part of the body that has hair, not just your head. Some people lose their eyelashes, eyebrows and pubic hair.

In most cases, your hair will grow back after chemotherapy treatments are finished. Sometimes hair doesn't grow back after very high doses of chemotherapy used for stem cell transplant. The chemotherapy drug docetaxel can sometimes cause permanent hair loss, even when given at standard doses.

Find out more about hair loss.

Diarrhea

Diarrhea is the frequent passing of loose, watery stools (poop). It happens because chemotherapy drugs often affect the cells that line the gastrointestinal (GI) tract. Many factors increase the risk of diarrhea, including the type and dose of chemotherapy. Diarrhea is often worse when combinations of chemotherapy drugs are given. You may have diarrhea soon after chemotherapy starts and it may continue for up to 2 weeks after having chemotherapy.

Find out more about diarrhea.

Constipation

Constipation is when your stool (poop) is hard, dry and difficult to pass. The stool becomes hard and dry if it moves too slowly through the large intestine (bowel) or if the intestine absorbs too much water from it.

Several different chemotherapy and supportive drugs can cause constipation.

Find out more about constipation.

Sore mouth and throat

You may have a sore mouth and throat because of chemotherapy's effect on the fast-growing cells that make up the lining of your mouth and throat. You may develop painful sores, ulcers or an infection in the mouth, throat or gums.

Many chemotherapy drugs can cause a sore mouth, but it happens more often when higher doses of drugs are used or if you are having chemoradiation for head and neck cancer. Your mouth may become sore anywhere from 5 to 10 days after chemotherapy starts. It often gets better on its own a few weeks after treatment is finished.

Find out more about a sore mouth and throat.

Mucositis

The mucous membrane is the protective lining of the entire gastrointestinal (GI) tract, from the mouth through the intestines. It also lines other body cavities and organs, including the bladder, urethra and ureters, vagina, sinuses and ears.

Chemotherapy can damage the rapidly dividing cells in the mucous membrane and make them inflamed. This is called mucositis. While mucositis can affect any mucous membranes in the body, it most often affects the GI tract. This can lead to painful ulcers, bleeding and infection. Mucositis usually goes away a few weeks after chemotherapy has finished.

Signs and symptoms of mucositis depend on where the mucous membranes are inflamed and may include:

Report any signs and symptoms that you have to your healthcare team. They can suggest ways to manage mucositis.

Taste and smell changes

Chemotherapy can damage the taste buds and cause taste changes. These changes can vary a lot from person to person. Common changes can include sweet foods tasting less sweet than usual or having a metallic taste in your mouth. You may also become more sensitive to smells. Smells that others don't notice may make you nauseous. It can take months for your sense of both smell and taste to return to normal after chemotherapy.

Find out more about taste changes.

Skin problems

Skin problems can happen during and after chemotherapy. Skin problems can include redness, itching, dryness, rash or nail changes. Your skin may also become more sensitive to or easily irritated by the sun while you are having chemotherapy.

Find out more about skin problems.

Eye and vision problems

Some chemotherapy drugs cause eye problems, such as blurry vision, watery eyes, dry eyes and sensitivity to light.

Find out more about eye and vision problems.

Fertility problems

Chemotherapy may cause fertility problems, depending on the type, dose and number of drugs used. Fertility is your ability to get or stay pregnant or get someone pregnant and have a child. Chemotherapy can damage the organs or glands in your reproductive system. This damage sometimes affects your fertility.

If fertility is important to you, talk to your healthcare team before you start chemotherapy.

Find out more about fertility problems.

Pain

Pain caused by chemotherapy can include aches or pain in the muscles, joints, gastrointestinal (GI) tract and headaches.

Find out more about pain.

Injection site problems

Most chemotherapy drugs are given through an IV. When the needle or catheter is put into the vein, you may feel some discomfort or pain. Because the chemotherapy drugs are going directly into your bloodstream, you probably won't feel any pain or discomfort when the chemotherapy drugs are given. Some drugs cause a slight burning feeling when they are first given into your vein. This is normal and will get better as the chemotherapy treatment continues.

Infiltration is when the chemotherapy drug fluid leaks into the surrounding tissues outside of the vein. It can be caused when:

  • the needle or cannula punctures the vein wall

  • a vein is too small to use or a needle is too large for the vein

  • the needle comes out of the vein

Signs and symptoms of infiltration may include swelling in the area of the IV, skin colour changes, pain or discomfort. The fluids may slow down or stop going into the vein. The injection site may also become infected.

Extravasation is when a chemotherapy drug that can burn or damage tissue leaks out of the vein and into the surrounding tissues. Chemotherapy drugs that can irritate tissues are called vesicants. They can cause significant tissue damage, including causing the cells that have come into contact with the vesicant drug to die. Some vesicant chemotherapy drugs include doxorubicin, epirubicin and vincristine.

Signs and symptoms of extravasation include pain, burning, redness, blisters, and not being able to move the arm where the injection is being given. Tell your healthcare team if any pain or burning at the injection site persists or gets worse during your chemotherapy treatment.

Both infiltration and extravasation are treated by stopping the treatment and removing the needle, applying a warm or cool compress to the area and elevating your arm above heart level. Other treatments may be offered, such as pain medicines or antibiotics and wound care.

Hearing problems

Some types of chemotherapy drugs can cause hearing problems. Some drugs can damage the inner ear, which can cause hearing loss. You may also have ringing in the ears (tinnitus).

Tell your healthcare team if your hearing has changed or if you are having problems hearing. They may lower the dose of chemotherapy or change your treatment to prevent further hearing damage.

Find out more about hearing problems.

Organ and nerve damage

Some chemotherapy drugs can damage organs and nerves in the body. Your healthcare team tries to limit the damage to normal cells, but damage to organs and nerves sometimes still happens. Organs that may be affected by chemotherapy include the:

Chemotherapy can also affect the nervous system and cause nerve damage, including peripheral nerve damage. It can start during chemotherapy treatments or develop later after treatment is finished. Find out more about nerve damage.

Memory, attention and other cognitive problems

Cognitive function refers to your thinking abilities. This includes functions related to communication, reasoning, perception, judgement, memory, learning, attention and problem solving.

Chemotherapy may cause problems with memory, attention or problem solving. This is sometimes called chemo brain or chemo fog. High doses of chemotherapy or chemotherapy given for a long time are more likely to cause cognitive problems. These may go away after chemotherapy is finished, but they sometimes last for a long time or become permanent.

Find out more about cognitive problems.

Sexual problems

Chemotherapy can affect your sexual health in different ways. Side effects such as fatigue, pain or nausea and vomiting can affect your desire to have sex. You may also experience side effects like vaginal dryness if chemotherapy causes treatment-induced menopause. Many sexual problems related to cancer can be treated or managed.

Find out more about sexual problems with male sex organs or sexual problems with female sex organs.

Negative drug reactions

A negative drug reaction is an unintended response by the body to a drug. An allergy is one type of reaction, which may happen while getting chemotherapy.

A drug reaction does not usually happen at home after treatment.

Some drugs are more likely to cause an allergic reaction over time (such as carboplatin) while others can cause a reaction the first time they are given (paclitaxel). Your healthcare team will monitor you carefully during your chemotherapy treatment. There are protocols in place to treat an allergic reaction if it happens.

Find out more about negative drug reactions.

Second cancers

A second cancer is another cancer that has started in the body of someone who has already been diagnosed with cancer. It is not related to the first cancer that was diagnosed. It may develop in the same organ or in a different place in the body.

Second cancers can be caused by cancer treatment, including chemotherapy. People who receive both chemotherapy and radiation therapy have the highest risk of developing a second cancer. The most common second cancer caused by chemotherapy is acute myeloid leukemia.

The risk is of developing a second cancer caused by chemotherapy is low. The benefit of treating the cancer that you have right now usually far outweighs the risk of developing a second cancer in future. If you're worried, talk to your healthcare team about whether your cancer treatments increase your risk of a second cancer. They can help you understand what you can do in future to manage your risk and keep it as low as possible.

Find out more about second cancers.

Expert review and references

  • American Cancer Society . Chemotherapy Side Effects . 2020 : https://www.cancer.org/.
  • Cancer Research UK . Late Side Effects of Chemotherapy . 2020 : https://www.cancerresearchuk.org/.
  • Healthwise Staff. Side Effects of Chemotherapy. HealthLink BC; 2023: https://www.healthlinkbc.ca/.
  • Slusser KM . Late effects of cancer treatment. Yarbro CH, Wujcki D, Holmes Gobel B, (eds.). Cancer Nursing: Principles and Practice. 8th ed. Burlington, MA: Jones and Bartlett Learning; 2018: 72: 2029 - 2044.
  • Velcheti V, Punekar SR. Handbook of Cancer Treatment-Related Symptoms and Toxicities. 1st ed. Philadelphia: Elsevier; 2022.

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