Anti-cancer drugs are designed to kill cells that are growing in an uncontrolled fashion. However, chemotherapy drugs also can damage normal cells, especially those healthy cells that divide rapidly. Cells vulnerable to this damage include, among others:

• Blood cells in bone marrow
• Digestive tract cells (mouth, stomach, intestines and esophagus)
• Reproductive system cells (sexual organs)
• Hair follicles

When healthy cells are damaged, a variety of side effects that range from mildly irritating to severely debilitating can occur. In rare cases, chemotherapy can cause long-term, permanent damage to the cells of vital organs such as the heart, kidney, bladder, lungs and nervous system. Chemotherapy can also result in delayed illnesses, such as secondary cancers that appear years later.

However, most side effects associated with chemotherapy are temporary and disappear as normal cells heal when chemotherapy sessions are ended. The risks of chemotherapy must always be weighed against the more immediate and potentially life-threatening cancer already present in the patient’s body.

Although most side effects associated with chemotherapy are temporary, they can have significant physical and emotional ramifications for a patient. In some cases, side effects can be severe enough to require hospitalization.

Common side effects associated with chemotherapy include infection, fatigue, nausea, pain, hair loss and, in some cases, anemia. Certain drugs may damage organs.

Fatigue

Fatigue, the most common side effect of chemotherapy, affects individuals differently. Some patients find they are mildly tired, while others experience a debilitating fatigue that is not easily relieved with rest. Fatigue occurs for a number of reasons, including anemia and the effect chemotherapy can have on the central nervous system. The degree of fatigue can be influenced by the patient's overall health and mindset, the nature and stage of the cancer and the chemotherapy drugs used.

Symptoms that accompany fatigue include:

• Weariness
• Weakness
• Lack of energy
• Decreased ability to perform physical and mental work
• Inability to think and concentrate
• Forgetfulness

Fatigue often lessens as the chemotherapy treatments make progress in destroying the cancer cells. State and federal laws may help protect patients who need flexible work schedules to accommodate the fatigue they may experience during chemotherapy.

Nausea and vomiting

Many patients have reported severe nausea and vomiting while undergoing chemotherapy treatments. Those at greatest risk include young patients, premenopausal women, patients who drink substantial amounts of alcohol and those with a history of motion sickness.

However, many new anti-nausea drugs have made these symptoms much less common and severe than they were in the past. Different drugs work for different people, and sometimes it is necessary to take more than one medication to obtain relief.

Pain

Chemotherapy drugs can damage nerves, which can cause the fingers, toes or other body areas to feel burning, numbness, tingling or shooting pains (neuropathy). Other forms of pain associated with chemotherapy include mouth sores, headaches, muscle pains and stomach pains. Most pain can be successfully treated using various medications, including analgesics and opioids.  

Hair, skin and nail problems

Alopecia or hair loss is a common side effect that occurs with many, though not all, chemotherapy medications. Hair may become thinner or fall out completely. It may be lost gradually or in thick clumps. Hair that remains on the body during chemotherapy may become dry and dull. Hair loss can occur in any area of the body, including the head, face, eyelashes, underarms, arms, legs and pubic area.

Hair usually grows back after treatments are completed, although some patients may see hair return even before treatments are finished. In some cases, hair will be a different color or texture than the patient’s original hair.

Skin problems associated with chemotherapy include redness, rashes, itching, peeling, dryiness, acne and increased sensitivity to the sun.

In some cases, the skin surrounding the vein used to administer chemotherapy drugs may darken. These darkened areas usually fade a few months after chemotherapy treatments end. Fingernails and toenails can sometimes become darkened, brittle, yellowed and cracked. Vertical lines or bands also sometimes develop across the nails.

Patients who are receiving chemotherapy intravenously should inform a physician right away if they feel burning or pain in the skin. This may indicate that the drug is leaking out of the vein, which can permanently damage tissues.

Anemia and blood-clotting issues

Chemotherapy often hampers bone marrow in its task of creating red blood cells, which carry oxygen throughout the body. When there are inadequate numbers of red blood cells, the condition is called anemia. Symptoms include shortness of breath, weakness and fatigue. Certain medicines such can combat this problem by boosting the production of red blood cells. If levels of red blood cells fall too low, a blood transfusion or drug such as erythropoietin may be necessary to raise the red blood cell count in the body.

Chemotherapy also hampers bone marrow’s ability to make platelets. These are the blood cells that help clot blood, and a reduction of platelets can cause patients to bleed or bruise more easily. Platelet transfusions and the use of growth colony stimulating factors can boost platelet counts. 

Heart damage

Certain chemotherapy drugs – especially daunorubicin and doxorubicin – can damage the heart in a small percentage of people who take these medications. In most cases, the damage occurs as changes to heart muscles. Symptoms that may accompany such damage include fatigue, shortness of breath, dizziness, dry cough, erratic heartbeats and swelling in the hands and feet.

Patients who take drugs that may cause heart damage will be closely monitored. If signs of damage are detected, treatment with the drug will be discontinued to prevent further damage. Most heart problems can be avoided or minimized by limiting the total cumulative dose of medication that the patient receives.

Lung and liver damage

Some patients may experience damage to the lungs when undergoing chemotherapy with medications such as bleomycin. This damage is more likely to occur in those who receive radiation therapy in conjunction with chemotherapy, and is much more likely in elderly patients. Symptoms include shortness of breath, dry cough and fever.

Liver damage may be experienced by patients who take certain anti-cancer medications, including methotrexate, cytarabine, high-dose cisplatin, high-dose cyclophosphamide, vincristine, vinblastine and doxorubicin. This damage is usually temporary. Symptoms include jaundice (yellowed skin and whites of the eyes), fatigue and pain on the right side below and behind the ribs.

Central nervous system issues

Chemotherapy medications can disrupt the central nervous system (brain and spinal cord), which can trigger confusion, depression and tiredness. Other symptoms associated with this damage include:

• Stiff neck
• Headache
• Nausea and vomiting
• Fever
• Seizures

These symptoms can usually be relieved by adjusting chemotherapy dosage levels.

Nerve and muscle effects

Anti-cancer drugs used in chemotherapy can cause peripheral neuropathy, a condition that affects the nervous system and causes symptoms in the hands or feet such as tingling, burning, weakness, pain and numbness.

Other drugs can cause muscles to become weak, tired or sore. These symptoms sometimes do not dissipate until up to a year after treatment ends.

Infection

Chemotherapy often reduces the ability of bone marrow to make white blood cells, which help fight many kinds of infections. For this reason, chemotherapy patients are often more susceptible to infections from bacteria found in the mouth, intestines and genital tract, and on the skin. Various preventive measures can be prescribed to reduce the risk of infection. Medicines called growth colony stimulating factors (G-CSF) can help boost the presence of white blood cells and are often given for preventative purposes. However, they may cause temporary bone discomfort. In addition, use of growth factors has been associated with an increased risk of developing leukemia. Patients must immediately report to their physicians any signs of fever, redness, swelling or unusual pain.

Mouth, gum and throat problems

Some drugs used in chemotherapy can cause sores in the mouth (stomatitis) and the throat (mucositis). Initially, the lining of the mouth may appear pale and dry. Later, the mouth, gums and throat may become sore, red and inflamed. The tongue may swell or become coated, leading to difficulty in swallowing, eating or talking. Patients who do not eat well after beginning treatments are most vulnerable to getting sores, which can bleed, ulcerate and become infected. Various medicines can treat mouth sores that may develop.

Diarrhea or constipation

Diarrhea may occur as a chemotherapy side effect if the drugs damage normal cells in the intestines. Patients should consult a physician if they have diarrhea that lasts more than 24 hours or that is accompanied by pain, cramping or bleeding. Factors that may increase the risk of diarrhea include:

• Drug dosage
• Treatment length
• Having a stomach tumor
• Combination of radiation and chemotherapy
• Lactose intolerance

Intravenous fluids may be necessary to replace water and nutrients that have been lost to diarrhea. Medicines may be prescribed to treat the diarrhea. Over-the-counter medications should not be used unless approved by a physician.

Chemotherapy can also cause constipation, especially in patients who are less active or do not consume enough fluid or fiber. Other factors that may increase the risk of constipation include prolonged bedrest, depression and use of pain medications.

Patients who do not have a bowel movement in one to two days should call their physician. Changes to diet, laxatives and stool softeners can help relieve constipation. These medications should not be taken without consulting a physician.

Allergic reactions

Some patients may have allergic reactions to various chemotherapy medications. A physician should be contacted if a patient has sudden or severe itching, rash, hives or wheezing or other breathing difficulties.

Radiation recall

Patients who have had radiation treatments may find that their skin turns light or very bright red during chemotherapy. This is known as “radiation recall,” and it can be accompanied by blistering and peeling of the skin. Symptoms may appear for hours or days. Symptoms can be eased by placing a cool, wet compress on the affected area and wearing nonirritating fabrics, including cotton bras for women who have had radiation treatments for breast cancer.

Kidney and bladder problems

Some chemotherapy medications can temporarily or permanently damage the bladder or kidneys. Urine may take on a medicine-like odor. Urine may change color (orange, red, green or yellow) due to the drug itself and not any organ injury. Patients who take drugs associated with these side effects will be closely monitored to ensure that no long-term damage occurs.

Flu-like symptoms

Some patients feel flu-like symptoms for several hours to a few days after a chemotherapy session. This is especially true in patients who are receiving chemotherapy in combination with biological therapy, which uses proteins to stimulate the body’s immune system. Symptoms may include:

• Muscle and joint achiness
• Headache
• Tiredness
• Nausea
• Slight fever
• Chills
• Poor appetite

These symptoms may last for one to three days and should be reported to a physician.

Fluid retention

Hormonal changes due to chemotherapy, side effects associated with a medication or the cancer itself may cause the body to retain fluid. Patients should consult a physician if they experience swelling or puffiness of the face, hands, feet or abdomen. Patients may be placed on a medication such as a diuretic to get rid of excess fluids. They may also be urged to avoid table salt and foods with high salt content.

Changes in sense of taste and smell

Patients undergoing chemotherapy often report that food tastes different. Also, many patients report a change in their sense of smell and notice an unusual sensitivity to certain scents. Anti-cancer drugs can alter taste and smell receptors. As a result, patients may develop:

• Either a dislike of or increased desire for sweet foods
• Dislike of foods with bitter tastes
• Dislike of tomatoes and tomato-based products
• Dislike of beef or pork
• Consistent metallic or medicinal taste in the mouth
• Sensitivity with feelings of nausea with certain smells

Changes to taste and smell receptors are usually temporary and disappear several weeks after the end of chemotherapy treatments.

Cognitive changes

In some patients, chemotherapy appears to affect brain function. It appears to worsen with larger doses of medications. Some of the brain’s activities that may be affected include concentration, memory, comprehension and reasoning.

These changes tend to be subtle, but noticeable to patients who experience them. It is sometimes referred to as “chemo-brain” or “chemo-fog.” At this point, little is known about why this occurs, although some studies have shown that the effects may last years for some patients. Patients can participate in therapy that will help them with their memory and problem-solving abilities.

Sex organ problems

In men, chemotherapy may lower the number of sperm cells or impair the movement of sperm. This can result in temporary or permanent infertility. Men may also experience damage to the chromosomes, which can result in birth defects in any offspring. Difficulty in maintaining erections is another possible side effect.

In women, anti-cancer drugs may affect the ovaries and reduce the amount of hormones they produce. Menstrual cycles may become irregular or cease. Damage to the ovaries can cause infertility that can be temporary or permanent. Chemotherapy can also trigger menopause in some women, or cause symptoms typically associated with menopause, including hot flashes and vaginal dryness. The combination of chemotherapy drugs and vaginal dryness may make women more susceptible to vaginal infections, including yeast infections.

All reproductive system changes in both men and women may be temporary or permanent. Patients should discuss the possibility of sperm or egg storage with their physicians prior to treatment.