Doctors often recommend chemotherapy as a treatment for cancer. Chemotherapy uses drugs that kill dividing cancer cells and prevent them from growing.

Many chemotherapy drugs have adverse effects that can be severe. However, if a doctor recommends a person has chemotherapy, this usually means that the benefits are likely to outweigh any adverse effects.

A person will often have chemotherapy as part of an overall treatment plan, which may also include surgery and radiation therapy. These treatments are effective in many cases of cancer. However, their effectiveness will often depend on the stage of the cancer, among other factors.

Taking to their doctor will help a person understand what to expect from chemotherapy.

Read on to find out more about chemotherapy and what it involves.

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Chemotherapy drugs treat cancer by stopping cancerous cells from dividing.


A healthy body constantly replaces cells through a process of dividing and growing. When cancer occurs, cells reproduce in an uncontrolled manner.

As a part of the body produces more and more cells, they start to occupy the space that useful cells previously took up.

Chemotherapy drugs interfere with a cancer cell's ability to divide and reproduce.

A single drug or combination of drugs can do this.

Treatment can either:

  • attack cancer cells throughout the body or
  • target specific sites or processes

What does chemotherapy do?

Chemotherapy drugs can:

  • prevent cell division
  • target the cancer cells' food source (the enzymes and hormones they need to grow)
  • trigger apoptosis, or the "suicide" of cancer cells

Some emerging treatments aim to stop the growth of new blood vessels that supply a tumor in order to starve it. Some scientists are concerned that this strategy might encourage the growth and spread of cancer in some cases.

However, in 2018, other researchers concluded that it might help some people.

Why use chemotherapy?

A doctor may recommend chemotherapy:

  • to shrink a tumor before surgery
  • after surgery or remission, to remove any remaining cancer cells and delay or prevent a recurrence
  • to slow disease progression and reduce symptoms in the later stages, even if a cure is unlikely

Chemotherapy is an invasive treatment that can have severe adverse effects both during the therapy and for some time after. This is because the drugs often target both cancer cells and healthy cells.

However, early treatment involving chemotherapy can sometimes achieve a complete cure. This makes the side effects worthwhile for many. Also, most of the unwanted symptoms go away after treatment finishes.

How long does chemo last?

The doctor will make a plan with the individual that specifies when treatment sessions will occur and how many they will need.

A course of treatment can range from a single dose on one day to a few weeks, depending on the type and stage of cancer.

Those who need more than one course of treatment will have a rest period to allow their body to recover.

A person might have treatment on one day, followed by a week's rest, then another one-day treatment followed by a three-week rest period, and so on. A person may repeat this several times.

Some people may find talking to a counselor about the mental and emotional aspects of cancer and chemotherapy helpful.

Blood tests

Blood tests assess the person's health and ensure that they will be able to cope with possible side effects.

Liver health: The liver breaks down chemotherapy chemicals and other drugs. Overloading the liver could trigger other problems. If a blood test detects liver problems before treatment, the person may have to postpone treatment until it recovers.

Low count of red or white blood cells or platelets: If these blood counts are low before treatment, the person may need to wait until they reach healthy levels before starting chemotherapy.

It is important to have regular blood tests during the treatment period to ensure that blood and liver functions remain as healthy as possible and monitor the effectiveness of the treatment.

How is the dose given?

Most people will receive chemotherapy in a clinical setting, but sometimes a person can take it at home.

Ways of taking chemotherapy include:

  • by mouth, as tablets, liquid or capsules
  • intravenously, as an injection or infusion
  • topically, onto the skin

In some cases, a person may be able to take the medication at home. However, they will need to make regular visits to the hospital to check their health and how they are responding to treatment.

The person must take the dose exactly as the doctor prescribes. If they forget to take a dose at the right time, they should call their doctor immediately.

Sometimes, a person will need a continuous dose. This means that they may have to wear a pump that delivers the drug slowly for several weeks or months. They can wear the pump as they go about their daily life.

Chemotherapy can produce adverse effects that range from mild to severe, depending on the type and extent of the treatment. Some people may experience few to no adverse effects.

A wide range of adverse effects can occur, including:

1: Nausea and vomiting

Nausea and vomiting are typical side effects. Doctors may prescribe antiemetic drugs to help reduce the symptoms.

Taking ginger or ginger supplements may help increase the effectiveness of antiemetics, according to one study.

2: Hair, nails, and skin

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Chemotherapy can lead to hair loss.

Some people may experience hair loss, or their hair may become thin or brittle a few weeks after starting some types of chemotherapy. It can affect any part of the body.

Wearing a special cap can keep the scalp cool during chemotherapy treatment, which may help prevent or reduce hair loss. However, if the treatment needs to reach the scalp, this will not be possible.

A counselor may offer advice about obtaining a hairpiece or another suitable covering. Most people find that their hair grows back once they have finished treatment.

Nails, too, can become flaky and brittle.

The skin may become dry and sore and oversensitive to sunlight. People should take care in direct sunlight, including:

  • avoiding the sun around midday
  • using sunblock
  • wearing clothes that provide maximum protection

Which foods can help a person's hair to grow back? Learn more here.

3: Fatigue

Some people may experience fatigue. They may experience this most of the time or only after certain activities.

To reduce fatigue, a person should try to:

  • get plenty of rest
  • avoid tasks that are overtiring

People who experience severe tiredness should talk to their doctor, as this could be a sign of anemia

4: Hearing impairment

The toxins in some types of chemotherapy can affect the nervous system, leading to:

A person should report any hearing changes to the doctor.

5: Infections

Chemotherapy can cause the number of white blood cells, which help protect the body from infection, to fall. This leads to a weakening of the immune system and a higher risk of infections.

People should take precautions to reduce the risk of getting an infection.

These include:

  • washing hands regularly
  • keeping any wounds clean
  • following appropriate food hygiene guidelines
  • getting early treatment if a person suspects an infection

A doctor may prescribe antibiotics to help reduce the risk.

6: Bleeding problems

Chemotherapy can reduce a person's platelet count. This means the blood will no longer clot as well as it usually does.

The person may experience:

  • easy bruising
  • more bleeding than usual from a small cut
  • frequent nosebleeds or bleeding gums

If the platelet count falls too low, the person may need a blood transfusion.

People should take extra care when doing activities such as cooking, gardening, or shaving to reduce the risk of injuring themselves.

7: Anemia

Red blood cells carry oxygen to all the tissues in the body. Chemotherapy can cause levels of red blood cells to fall. This will lead to anemia.

Symptoms include:

  • tiredness
  • shortness of breath
  • heart palpitations

Consuming extra iron may help the body may more red blood cells. People can take in extra iron from their diet. Good food sources include:

  • dark green leafy vegetables
  • beans
  • meat
  • nuts
  • prunes, raisins, and apricots

Anyone who experiences severe or worsening symptoms of anemia should call their doctor. Some people may need a blood transfusion.

8: Mucositis

Mucositis, or inflammation of the mucous membrane, can affect any part of the digestive system, from the mouth to the anus.

Oral mucositis affects the mouth. It often appears 7–10 days after starting treatment. Symptoms, which can vary according to the chemotherapy dose, can make it painful to eat or talk. Some people experience a burning pain in their mouth or on their lips. If bleeding occurs, it may mean a person has or is at risk of infection. Symptoms typically disappear a few weeks after finishing treatment.

A doctor may prescribe medication to help prevent or treat it.

9: Loss of appetite

Chemotherapy, cancer or both can affect how the body processes nutrients, which can lead to a loss of appetite and weight loss.

The severity depends on the type of cancer and chemotherapy treatment, but the person usually regains their appetite after treatment.

Tips to resolve this include:

  • eating smaller, more frequent meals
  • consuming nutrient rich drinks, such as smoothies, through a straw, to help maintain fluid and nutrient intake

People who find it too difficult to eat may need to spend time in the hospital, where healthcare professionals can provide nutrition intravenously or through a feeding tube.

10: Pregnancy and fertility

People often lose interest in sex during chemotherapy, but this usually returns after treatment.

Fertility: Some types of chemotherapy can reduce fertility in men and women. This often, but not always, returns after treatment is over. However, people who wish to have children in the future may consider freezing sperm or embryos for later use.

Pregnancy: It is not entirely clear how different types of chemotherapy may affect a growing fetus. If a woman needs chemotherapy during pregnancy, a doctor may recommend waiting until after the first 12–14 weeks because this is the time when the fetus's organs are developing rapidly. Chemotherapy can begin after the first trimester if a doctor considers it necessary.

A woman who is pregnant will receive the last course of chemo about 8 weeks before the delivery date to reduce any risk of infection in both mother and baby around the time of birth.

Because chemotherapy can have severe adverse side effects, it may be best to avoid becoming pregnant while having treatment. A doctor can advise on suitable birth control methods.

Anyone who is pregnant or who becomes pregnant during chemotherapy treatment should tell their doctor at once.

11: Bowel problems

Chemotherapy can also lead to diarrhea or constipation as the body expels damaged cells.

Symptoms often begin a few days after treatment starts.

12: Cognitive and mental health problems

Up to 75% of people report problems with attention, thinking, and short term memory during chemotherapy. For up to 35% of these people, cognitive problems may continue for months or years after treatment.

Chemotherapy can also lead to difficulty with reasoning, organizing, and multitasking. Some people experience mood swings and depression.

Both the treatment itself and a person's anxiety about the condition may also trigger or worsen these symptoms.

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A person can speak to their doctor about the most suitable cancer treatment.

Types of chemotherapy include:

Alkylating agents: These affect the DNA and kill the cells at different stages of the cell life cycle.

Antimetabolites: These mimic proteins that the cells need to survive. When the cells consume them, they offer no benefit, and the cells starve.

Plant alkaloids: These stop the cells from growing and dividing.

Antitumor antibiotics: These stop the cells from reproducing. They are different from the antibiotics people use for an infection.

The doctor will recommend a suitable option for the individual. They may recommend combining chemotherapy with other options, such as radiation therapy or surgery.

Factors affecting the type of chemotherapy and how well it will work include:

  • the location, type, and stage of the cancer
  • the person's age, overall health, and any existing medical conditions

How does a person know if chemo is not working? Find out here.

The outlook for a person receiving chemotherapy will depend largely on the type, stage, and location of the cancer and their overall health. In some cases, it can achieve complete remission.

There can be adverse effects, however, and a person may need to adjust their lifestyle or work routine during treatment. However, these usually resolve after treatment finishes.

Before starting treatment, a person may wish to discuss with their doctor:

  • why they are recommending chemotherapy
  • what the other options are
  • which types are available
  • how much it will cost
  • what to expect in terms of adverse effects

They should also speak to:

  • their insurance provider about covering the costs
  • their employer about how treatment may affect their work routine
  • their loved ones about what to expect

A doctor can often put a person in touch with a counselor or support group, who may help.

Q:

I have known some people who declined chemotherapy when they had later stage cancer. Is this a good idea?

A:

Each person’s situation is different. Nobody should make a decision without exploring all the available options. Having an honest, open discussion regarding outcome potentials and expectations with friends, family, and their doctors is very important.

Alan Carter, PharmD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.