Part III: Side Effects of Chemotherapy

This is the third article in a three-part series on chemotherapy. For an overview on chemotherapy, read Part I: Understanding Chemotherapy. For information on choosing chemotherapy, questions to ask your doctor, preparing for treatment, and what to expect during treatment, read Part II: Chemotherapy—Your Personal Experience.

Why chemotherapy causes side effects

Chemotherapy is designed to slow actively growing cancer cells; however, these drugs do not distinguish between an actively growing cancer cell and an actively growing healthy body cell. Side effects occur when the chemotherapy disrupts the healthy cells that maintain the body's appearance and function. Many patients experience side effects, but many of these unintended problems can be managed and disappear once chemotherapy is completed.

Side effects are often treatable, and you are encouraged to talk with your doctor if you experience any side effects. It is important to understand that chemotherapy is easier to tolerate today than even a few years ago. Experiencing side effects does not mean the treatment is working better. Similarly, the absence of side effects does not mean that the treatment is not working. Furthermore, chemotherapy can be very effective in treating cancer and relieving cancer symptoms and the potential of side effects should not deter a patient from getting chemotherapy.

Common side effects of chemotherapy

Different drugs cause different side effects. Although specific side effects may be predictable for certain classes of drugs, each person's overall experience with chemotherapy is unique. Talk with your doctor about side effects, so they can be promptly treated or better managed. For more information, read the Managing Side Effects of Cancer Treatment Chat Transcript and PLWC's Managing Side Effects section.

With chemotherapy, a patient may experience one or more of the following side effects. Some people do not experience any treatment side effects.

Hair loss. Patients receiving chemotherapy may lose hair throughout their body. After a few chemotherapy treatments, hair may begin to fall out gradually or in clumps. Fortunately, hair loss from chemotherapy is almost always temporary.

Nausea and vomiting. Many patients associate chemotherapy with nausea and vomiting, but new medications can minimize or prevent these side effects in the majority of people. Sometimes patients experience delayed vomiting (vomiting up to 24 hours after treatment) or anticipatory vomiting (vomiting before the next treatment after a bad experience from the first treatment). Talk with your doctor if you experience either of these side effects.

Diarrhea. Loose or watery bowel movements occur in three out of four people who receive chemotherapy because of the damage to rapidly dividing cells in the gastrointestinal (digestive) tract. Untreated diarrhea can be serious and even life threatening if it leads to dehydration and malnutrition (poor nutrition from an improperly balanced diet). Tell your doctor if you experience diarrhea, so treatment can begin promptly.

Constipation. Patients receiving chemotherapy may develop constipation, the infrequent or difficult passage of stool. Often, pain medications cause constipation. Also, patients sometimes unknowingly increase their risk of constipation by not drinking enough fluids, eating balanced meals, or getting enough exercise. Talk with your doctor about ways to relieve the symptoms of constipation.

Fatigue. The most common chemotherapy symptom reported by patients is fatigue, or feeling tired and lacking energy. Chemotherapy may cause or increase fatigue, so plan your days to include short naps and light exercise to help increase your energy levels. For more information, read the PLWC Feature: Coping With Cancer-Related Fatigue.

Sores in the mouth and throat. Chemotherapy can cause sores to develop in the mouth or throat by damaging the cells that line these areas. The sores usually develop five to 14 days after receiving chemotherapy and often heal completely when treatment is completed. Patients getting chemotherapy who have poor diets and/or dental hygiene increase their risk of mouth and throat sores, which, in turn, increases the risk of serious infections.

Blood disorders. Chemotherapy affects production of new blood cells from the bone marrow, the spongy, red tissue in the inner part of bones. Your doctor will monitor the levels of red blood cells (RBCs) and white blood cells (WBCs) using a test called a complete blood count (CBC). Low RBCs result in anemia, which decreases the body’s ability to carry oxygen throughout the body. As a result, you may feel fatigued, dizzy, or short of breath. A lower than normal number of WBCs, or leukopenia, increases your risk of infections. A second type of test, called a platelet count, measures the number of platelets in your blood. Thrombocytopenia, a shortage of platelets, reduces your blood’s ability to clot and you may bleed or bruise more easily. Your doctor can treat all three of these deficiencies using newer medications that stimulate the bone marrow to make more blood-forming cells that develop into RBCs, WBCs, and platelets.

Nerve and muscle effects. Some chemotherapeutic drugs cause nerve and muscle damage, resulting in one or more of the following symptoms:

  • Tingling
  • Burning
  • Weakness or numbness in the hands and/or feet
  • Weak, sore, tired, or achy muscles
  • Loss of balance
  • Shaking or trembling
  • Stiff neck
  • Headache
  • Visual problems
  • Walking problems
  • Hearing difficulties
  • Clumsiness

These symptoms usually decrease when the chemotherapy dose is lowered or treatment is stopped; however, in some cases, the damage is permanent.

Changes in thinking and memory. Some patients getting chemotherapy may describe their minds as being in a fog—unable to concentrate, find the right word, or remember things, such as where they put their keys. This experience of "chemobrain" or "chemofog" is subtle but can be troublesome to those who experience it. Programs to improve memory and problem-solving abilities help to reverse these side effects, but some people have persistent difficulties with certain mental tasks even after chemotherapy is completed. For more information, read CancerCare's Chemobrain Information Series: Cognitive Problems After Chemotherapy.

Reproductive and sexual issues. Chemotherapy can have an effect on reproduction and sexuality. Discuss any concerns with your doctor before treatment begins. During treatment, men are encouraged to use condoms during sexual intercourse for the first 48 hours after chemotherapy because some of the drug(s) may end up in the sperm. Because some types of chemotherapy cause genetic changes in sperm or eggs that could lead to birth defects, both men and women are encouraged to use birth control throughout their treatment. For more information, read PLWC's Sexuality section.

Reproductive and sexual issues for men. Chemotherapy may cause temporary or permanent infertility (inability to father a child). Those who wish to have children after chemotherapy can consider freezing their sperm for future use. Impotency (inability to perform sexually) due to chemotherapy is rare, but certain drugs may affect erections and sexual desire by reducing the amount of testosterone produced. A few chemotherapeutic drugs permanently damage parts of the nervous system and may play a role in impotency by injuring the nerves that control erection.

Reproductive and sexual issues for women. Chemotherapy can damage the ovaries and result in temporary or permanent infertility. However, birth control is important even if your periods are irregular or absent; pregnancy could interfere with your cancer treatment and/or the baby's development. Depending on your age and the drugs used, chemotherapy can also lead to early menopause, which may be temporary or permanent. Tissue changes associated with menopause can make intercourse uncomfortable and bladder and/or vaginal infections more likely.

Appetite. Loss of appetite during chemotherapy can seriously affect a patient's ability to regain health. Without proper nutrition, the body cannot recover as well from the damage caused by chemotherapy. Patients who maintain their weight cope with side effects and fight infections better. If you feel too tired to eat, have lost your appetite, or have mouth or throat problems that make it difficult or painful to eat, your doctor may recommend that you be given nutrition intravenously until you are able to eat again. You may also ask your doctor to recommend a dietitian who can help you to maintain your weight.

Pain. Chemotherapy can cause pain, including mouth sores, headaches, muscle pains, and stomach pains, as well as burning, numbness, or shooting pains (most often in the fingers and toes) from nerve damage. Not everyone who receives chemotherapy experiences pain. For those who do, it's important to know that most pain can be relieved. It is helpful if you can describe for your doctor where you feel pain, what it feels like (sharp, dull, throbbing, or steady), how strong it is, how long it lasts, and what kinds of things reduce or increase its intensity. For more information, read PLWC Feature: Cancer Pain.

Long-term side effects. Chemotherapy side effects usually disappear at the end of treatment. However, side effects may recur or develop later. Certain types of chemotherapy are associated with permanent organ damage to the heart, lung, liver, kidneys, or reproductive system. Cognitive (thinking, concentrating, memory) issues remain for some people, and children who have received chemotherapy for cancer treatment may have development problems. Nervous system changes can develop months or years after treatment. Finally, cancer survivors have a higher risk of developing second cancers. Follow-up care is an essential component of health care for all cancer survivors. For more information, read the 2004 Meet the Expert Cancer Advances: Survivorship—Increasing Survival, Improving Lives and the
Institute of Medicine Cancer Survivorship Report: From Cancer Patient to Cancer Survivor: Lost in Transition.

Additional resources

National Cancer Institute (NCI): Chemotherapy and You: A Guide to Self-Help During Cancer Treatment

CancerCare: Understanding and Managing Chemotherapy Side Effects booklet based on an April 2005 Telephone Education Workshop

Mayo Clinic: Chemotherapy: Using chemicals to treat cancer

Mayo Clinic: Chemobrain: When cancer treatment disrupts your thinking and memory skills

American Cancer Society (ACS): What Are the Possible Side Effects of Chemotherapy?

ACS: Side Effects of Chemo on Reproduction and Sexuality in Men

ACS: Side Effects of Chemo on Reproduction and Sexuality in Women

ACS: How Do I Deal With Losing My Hair?

ACS: Some Cancer Doctors Underestimate Chemotherapy Side Effects Managing Chemo Side Effects Ask-the-Expert Conference: Chemotherapy Updates

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