10 Worst Side Effects of Cancer Treatment


Cancer and cancer treatment can cause many physical side effects for patients; some are easily controlled and others require specialized care. Everyone has different reactions and side effects from cancer treatment. Here are some practical tips for coping with some of the most common side effects.

Nausea and vomiting

Nausea and vomiting is a common side effect of chemotherapy. Patients may feel sick to their stomach every day, but the condition is usually worse on days when they receive chemotherapy.

Whenever possible, it is best to prevent nausea and vomiting from starting. Many medications are available to help reduce or stop vomiting. If your elderly loved one suffers from nausea and vomiting due to cancer treatment, your doctor may prescribe antiemetic medications. These medications might be taken before cancer treatment, to help prevent or alleviate symptoms. In addition, many people find that behavioral treatments can help control nausea and vomiting. Methods such as distraction, relaxation, and positive imagery can help change the expectation and fear of nausea and vomiting. In some situations, the doctor may be able to recommend another treatment plan that is less likely to cause vomiting.

Another tip for controlling nausea and vomiting: Learn the best time for your parent to eat and drink. Some people feel better when they eat a little just before treatment. Others feel better when they have nothing to eat or drink before treatment. Have your parent eat less greasy, fried, salty, sweet, or spicy foods if they feel sick after eating them.

Hair loss

Hair loss due to cancer treatment is not preventable. The change in physical appearance can be traumatizing, but it is also a necessity as part of the treatment and road to recovery. Therefore, before their hair falls out, help your parent think about how to prepare for and cope with it. Some people choose to cut their hair short before treatment. Others shave their head at the first sign of hair loss. Wigs are the answer for some, while others refuse to wear them. Scarves are another option.

Talking about feelings with a counselor, someone with a similar experience, family member, or friend may also provide comfort. Also, it may be helpful to talk about inevitable hair loss with family and friends, especially children, before it occurs. If children know to expect changes in the physical appearance of someone they are familiar with, it helps reduce feelings of anxiety.

To care for hair and scalp during cancer treatment:

  • Use a mild shampoo, such as a baby shampoo
  • Choose a soft hairbrush
  • Avoid blow-drying with high heat
  • Do not use chemical products such as hair color
  • Choose a soft, comfortable covering for bed pillows
  • Use sun protection on the scalp when outdoors
  • Cover the head during the cold months to prevent loss of body heat

To care for hair as it re-grows:

  • Limit washing the hair to twice a week
  • Limit the amount of brushing
  • Don't curl or blow dry hair with high heat
  • Massage the scalp to remove dry skin and flakes
  • Use a wide-tooth comb to gently style the re-grown hair.
  • Avoid chemical products until the hair is at least 3 inches long

Your parent's hair may grow back 3 to 6 months after treatment is over. In some cases, if your parent received a very high dose of radiation, the hair may not grow back. Talk with your doctor or nurse to learn what you can expect.


If your parent is in pain from cancer or cancer treatments, there may be some ways to lessen it. There are many medicines to help lower or get rid of pain. Talk with your doctor to learn about medicine that can help. Ask what other things, like massage or acupuncture, could also help. Remember, being in less pain will help your parent cope by feeling stronger and better.

To get the most of pain medicine:

  • Ask how much pain medicine your parent should take. Make sure they take the right amount of medicine at the right time, on a consistent basis.
  • Ask when to take the pain medicine. Take the pain medicine on time. If your parent takes the pain medicine too late, it may not work as well.
  • Don't stop taking the pain medicine unless the doctor tells you to.

Call the doctor or nurse if:

  • The pain isn't getting better or going away
  • The pain comes on quickly
  • Your parent feels new pain
  • The pain medicine is not working as fast or for as long as it used to

Keep track of the pain. Each day, help your parent keep track, in writing, any pain they feel. This will help your doctor to manage the pain. Write down this type of information:

  • Are there certain times of the day when the pain is worse?
  • Are there activities or movements that make the increase the pain?
  • Are there activities that your parent is unable to do because of the pain?
  • Is the pain is dull, sharp, burning, shooting, throbbing?
  • Rank pain on a scale of 1 to 10, where "10" is the most pain and "1" is the least pain
  • Things that make the pain feel worse (and what makes it feel better)

It is normal for the body to get used to the pain medicine. It may not work as well as it did at first. This is called "tolerance." It happens to many people. If this happens to your parent, your doctor may change their pain medicine or change the way they take it.


People with cancer are more likely to develop infections because both cancer and cancer treatments can weaken the immune system. The immune system includes white blood cells, the skin, lymph nodes, white blood cells, leukocytes, bone marrow, spleen, bone marrow.

Cancer and cancer treatment can interfere with the functioning of the immune system in several ways:

  • The immune system is less able to protect against other infections because it is busy fighting the cancer
  • Chemotherapy may cause the bone marrow and other parts of the immune system to malfunction, lowering the production of white blood cells
  • Radiation therapy to bones in the pelvis, legs, chest, or abdomen can affect bone marrow, which increase risk of infection
  • Lack of sleep, stress, poor diet, and other side effects of cancer treatment may weaken the immune system

If an elderly person's white blood cell count is low, the doctor may prescribe medications, to encourage the body to make more white bloods cells to reduce the risk of an infection.

Common medications for patients at high risk for developing an infection (such as those who are undergoing chemotherapy or radiation therapy) as well as those who have already developed an infection include antibiotics or antifungal medications.
If patients develop a fever, they might need to be hospitalized, and receive intravenous (IV) antibiotics.

Talk to your doctor right away if your parent experiences any of the following signs of infection:

  • A fever of 100.5°F or higher
  • Chills or sweating
  • Sore throat or sores in the mouth
  • Abdominal pain
  • Pain or burning when urinating or frequent urination
  • Diarrhea or sores around the anus
  • A cough or shortness of breath
  • Any redness, swelling, or pain, particularly around a cut or wound

Fatigue and Anemia

Cancer-related fatigue is a persistent sense of tiredness or exhaustion from cancer or cancer treatment. Fatigue can get so bad that people sometimes report simple tasks that require little effort, such as walking across room, are exhausting and even seemingly impossible. It is common for fatigue to appear after:

  • A few days after chemotherapy treatment
  • A few weeks after beginning radiation treatment
  • Following treatment with immunotherapy (also known as biologic therapy)

When a cancer patient is feeling fatigued, they may be tempted to avoid or skip cancer treatments. This isn't the answer! If your parent is suffering from chronic fatigue, the first step is talk to your parent's doctor. To understand the fatigue problem, the doctor may ask at what times your parent feels especially tired and whether the fatigue affects the ability to perform regular activities. The doctor might also take blood samples to determine whether anemia (a low red blood cell count) or another problem may be causing fatigue. Here are some questions to ask the doctor about cancer-related fatigue:

  • What problems should I call you about?
  • What medicine or treatments can help?
  • What foods and drinks are best?
  • How much liquid should my parent drink each day?
  • What exercises can help my parent feel better?

The doctor might suggest supplements such as iron, folic acid, B12, and he/she might prescribe medication.

Eating foods high in iron, such as red meat, beans, almonds, broccoli, and enriched breads and cereals might also help. Exercise is another good solution – but be sure to check with doctor before your parent begins any exercise regimen. Even exercise such as walking a few minutes every day has shown to be help. Cancer patients who exercise moderately experience less overall fatigue and report improvement in appetite.

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Cancer takes a toll on both the body and mind. Your loved one is coping with many different things now. He/she may feel overwhelmed. Pain and medicines for pain can also make them feel anxious or depressed. And they may be more likely to feel this way if they have had these feelings before. Here are some signs of anxiety:

  • Feeling very tense and nervous
  • Racing heartbeat
  • Sweating a lot
  • Trouble breathing or catching your breath
  • A lump in your throat or a knot in your stomach
  • Sudden fear

Feeling anxious can be normal. But if it begins disrupting daily life, ask for help from the members of your health care team. They can recommend someone for your loved one to talk to. Counseling from a mental health professional has been shown to help many people cope with anxiety. Your doctor can also give medicines that will help. Some of the complementary and alternative medicine choices for pain may work for anxiety as well.


Another side effect of cancer treatment is constipation. Constipation is a problem in which stool becomes hard, dry, and difficult to pass, and bowel movements do not happen very often. Other symptoms may include painful bowel movements, and feeling bloated, uncomfortable, and sluggish. Chemotherapy, as well as other medicines (especially those used for pain), can cause constipation. It can also happen when people become less active and spend more time sitting or lying down.

Here are some ways to help manage constipation:

  • Drink plenty of fluids each day. Many people find that drinking warm or hot fluids helps with bowel movements.
  • Be active-- walking, water aerobics, or yoga. If your loved one cannot walk, talk with your doctor or nurse about ways he/she can be active, such as doing exercises in bed or a chair.
  • Ask your doctor, nurse, or dietitian if your loved one should eat more fiber. He or she may suggest bran, whole wheat bread and cereal, raw or cooked vegetables, fresh and dried fruit, nuts, and popcorn and other high-fiber foods.
  • Let your doctor or nurse know if your loved one is having pain or discomfort from not having a bowel movement. He or she may suggest an enema or take a laxative or stool softener. Check with your doctor or nurse before using any of these.
  • Ask your doctor about giving laxatives when pain medication is started. Taking a stool softener at the same time your loved one starts taking pain drugs may prevent the problem.

Loss of Appetite

Eating and appetite changes are common in the later stages of cancer. As cancer progresses, your loved one's appetite may become poor.

On the other hand, your loved one may be eating enough, but the body can't absorb the nutrients. This can cause weight, fat, and muscle loss.

Nutrition goals may become less important at this time. The goal should not be weight gain or improving eating but rather comfort and symptom relief.

Your nurse, dietitian, and other members of your health care team can help. They can help you decide on changes to your loved one's diet that may be needed to keep them as healthy as possible. There are also new drugs to improve appetite and get rid of nausea. Ask your health care team about them.

Sleep Problems

Illness, pain, drugs, being in the hospital, and stress can cause sleep problems. Sleep problems may include:

  • Having trouble falling asleep
  • Sleeping only in short amounts of time
  • Waking up in the middle of the night
  • Having trouble getting back to sleep

To help with your sleep problem, try:

  • Reducing noise, dimming the lights, making the room warmer or cooler, and using pillows to support the body
  • Dressing in soft, loose clothing
  • Going to the bathroom before bed
  • Eating a high-protein snack 2 hours before bedtime (such as peanut butter, cheese, nuts, or some sliced chicken or turkey)
  • Avoiding caffeine (coffee, teas, colas, hot cocoa)
  • Keeping regular sleep hours (avoid naps longer than 15-30 minutes)
  • Talking with your health care team about drugs to help your loved one sleep. These may give relief on a short-term basis.


You may start noticing signs that your loved one feels confused. This can occur in some people with advanced stage cancer. It can also be caused by some medicines. Confusion may begin suddenly or come and go during the day. Possible signs include:

Sudden changes in feelings (such as feeling calm then suddenly becoming angry)
Having trouble paying attention or concentrating (such as feeling easily distracted, having trouble answering questions, or finding it harder to do tasks that involve logic, such as math problems)
Memory and awareness problems (such as forgetting where you are and what day it is or forgetting recent events)

If you notice these signs, talk to your health care team to try to find out the cause. Meanwhile, try one or more of the following to help relieve confusion:

  • Go to a quiet, well-lit room with familiar objects.
  • Reduce noise.
  • Have family or loved ones nearby.
  • Put a clock or calendar where it can be seen.
  • Limit changes in caregivers.
  • Ask your health care team about drugs that may help.

Source: The National Cancer Insitute, https://www.cancer.gov/

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