This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science

This page was updated on June 1, 2022.

Chemotherapy, often referred to as chemo, is one of the most common treatment options for many cancers. It may be used alone or paired with other treatments to destroy cancer cells.

What is chemotherapy?

Chemotherapy is a cancer treatment that uses anti-cancer drugs that target rapidly growing cancer cells either throughout the body or in a specific area of the body.

When chemotherapy drugs travel through the bloodstream to reach cancer cells, it's known as systemic chemotherapy. When the drugs are directed to a specific area of the body, it's called regional chemotherapy.

This article will cover:

How does chemotherapy work?

Chemotherapy is designed to destroy cancer cells that multiply, grow and divide in an out-of-control way, which is what cancer cells do. This treatment aims to stop those cancer cells from continuing to divide and cause disease.  

Chemotherapy vs. radiation

Both radiation therapy and chemotherapy work by destroying cancer cells, but they do so in different ways. With chemotherapy, drugs are used to target and kill cancer cells or stop them from dividing, while radiation therapy delivers high-energy X-rays to destroy cancer cells.

Chemotherapy may be used in the ways listed below:

Primary treatment: Chemotherapy may be used as a primary treatment to destroy cancer cells. When the cancer doesn’t return after treatment, it’s referred to as curative therapy.

Neoadjuvant therapy: Chemotherapy is administered before another treatment, like surgery, to shrink the tumor.

Adjuvant therapy: Chemotherapy is given after another treatment, such as radiation therapy, to destroy remaining cancer cells.

Palliative therapy: Chemotherapy is used to relieve symptoms of advanced cancer.

Chemotherapy types

The patient’s care team will identify the type of chemotherapy that’s most likely to inhibit cancer cell growth based on the cancer stage, type and location. The most common chemotherapy types are listed below.

Alkylating agents: These drugs damage the cancer cell's DNA.

Antimetabolites: Drugs in this category imitate the molecules that cancer cells require to mutate and grow.

Antitumor antibiotics: These chemotherapy drugs alter the genetic code of cancer cells.

Topoisomerase inhibitors: Drugs in this group block the enzyme that cells need to grow and mutate.

Mitotic inhibitors: These drugs halt the division of cells.

Plant alkaloids: These chemotherapy drugs, which are made of plants, block enzymes that cancer cells use to divide and grow.

How is chemotherapy administered?

How and where chemotherapy drugs may be given depends on a variety of clinical factors and personal patient preferences. Patients may receive chemotherapy at home, in a clinic or outpatient care center, at a hospital or doctor’s office.

Chemotherapy drugs may be administered in the following ways.

Orally: In pill or liquid form are taken by mouth.

Infusion: Delivered directly into a vein through an intravenous drip. This process may take several hours.

Injection: Delivered through a needle injected into a vein, muscle or under the skin.

Topically: In cream form and spread on the skin.

Intrathecal: Delivered directly into the central nervous system.

Intraperitoneal: Administered directly into the abdominal cavity.

Chemotherapy drugs are very powerful and may cause side effects in caregivers and family members who come in contact with them. Patients should talk to their doctor before deciding whether to administer their own chemotherapy drugs (in pill, liquid or cream form), or whether to have them given by a medical professional. Patients who may require frequent injections or infusions may opt to get a port or catheter through which drugs may be administered more efficiently and with less pain. How the chemotherapy drugs are administered and whether a patient needs a catheter such as a PICC line will depend on a variety of factors, including:

  • The drug prescribed
  • The cancer being treated
  • The stage of the disease
  • The health of the patient
  • The patient’s health history, including previous cancer treatments
  • The patient’s personal preference

Depending on each patient's treatment needs, chemotherapy drugs may be given in combinations, in addition to, or before and/or after other treatments, such as cancer surgery, targeted therapy or radiation therapy.

Expert cancer care

is one call away.
appointments in as little as 24 hrs.

What to expect from chemotherapy

Like every patient and every cancer type, every chemotherapy treatment plan is different and tailored to the patient’s specific disease, treatment goals and personal preferences. If chemotherapy is part of the patient's treatment plan, the medical oncologist and care team will share the options and coordinate dosages and schedules. In most cases, chemotherapy is administered in time frames called cycles. The length of each cycle and the dosages recommended within each cycle depends on many factors, including the patient's diagnosis and treatment goals.

If patients choose to administer their own chemotherapy drugs, the doctor may offer advice about the dosage schedule, amounts and safety protocols for handling drugs. If infusion is the best option, the care team may advise when and where to go and how long the treatments will take.

Chemotherapy preparation

Since chemotherapy infusion sessions may take several hours, patients may want to prepare for a long visit to the clinic, infusion center, hospital, or wherever treatment is administered.

Chemotherapy questions to ask the cancer care team

Before deciding whether chemotherapy is the right treatment, it’s important to be informed and learn as much as possible about the risks and benefits and what to expect. Don’t hesitate to ask the cancer care team any questions that may help with preparation.

The American Cancer Society offers a helpful and comprehensive list of questions to ask the doctor or nurse before starting chemotherapy treatment. Some of those questions include:

  • Which chemotherapy drugs will I be given, and how will they be given to me?
  • How often will I need to get chemotherapy?
  • How long will my treatments last?
  • Will I also need surgery, radiation or both? If so, when and why? What results can I expect?
  • What can I do to get ready for treatment and decrease the chance of side effects?
  • Can I take my other medicines, vitamins and/or supplements while getting chemotherapy?
  • What will we do if this chemotherapy doesn’t work?

After chemotherapy

Expect to follow up with a medical oncologist or other members of the care team after every chemotherapy session. If and when a follow-up visit is necessary depends on the patient's specific needs and where they are in their treatment.

Things not to do while on chemotherapy

It's important to take some precautions during and after chemotherapy to ensure that it takes effect and doesn’t cause further harm.

Don’t engage in activities that may put the immune system at risk. Chemotherapy may weaken the immune system and put patients at risk of an infection. Stay out of crowded spaces and avoid people who are sick or may be sick. Wash hands frequently, and avoid eating raw or undercooked foods.

Avoid contact with bodily fluids. Some chemotherapy drugs may be passed on to others. These drugs may be found in body fluids, including mucus, sweat, tears, semen, urine, vomit or stool. Keep bathrooms clean and immediately wash towels or clothing that may have fluids on them. Caregivers should wash hands frequently and wear double gloves when necessary.

Don’t get sunburned. Some patients find that they’re more sensitive to sunlight during and after chemotherapy, so it’s important to wear sunscreen and protective clothing (such as hats and long-sleeved shirts) in the sun.

Don’t eat large meals. The side effects of chemotherapy (including nausea, mouth sores and vomiting) may make it difficult for patients to eat a complete meal. Try to focus on eating smaller meals throughout the day.

Don’t consume excessive amounts of alcohol. Chemotherapy may make patients more sensitive to alcohol. Some chemotherapy drugs don’t interact well with these drinks, so consult a doctor before drinking alcoholic beverages during chemotherapy.

Throughout treatment, a medical oncologist will monitor the progress of the patient’s chemotherapy regimen and modify his or her treatment plan accordingly.

Managing chemotherapy side effects

Because chemotherapy drugs kill rapidly growing cancer cells, they also can harm healthy cells in the process. This can cause several different side effects.

It’s important to remember that one person's reaction to chemotherapy may be different from someone else’s, even when taking the same chemotherapy regimen. The severity of these side effects depends on the patient's health, age and the type of chemotherapy drugs given.

Chemotherapy side effects may include those listed below.

Fatigue: Fatigue is a common reaction to chemotherapy due to the treatment itself and the toll it takes on the patient's body and mind, but also other physiological changes from chemotherapy that cause fatigue, like anemia or appetite loss.

Hair loss: Some types of chemotherapy drugs damage the cells that are responsible for hair growth.

Anemia (low red blood cell counts): Some types of chemotherapy drugs make it harder for bone marrow to make new red blood cells.

Infection: Chemotherapy drugs may impede the production of new white blood cells, which help fight infection.

Easy bruising and bleeding: When chemotherapy drugs affect the bone marrow's ability to make platelets (which help blood clot when a patient bleeds), the patient may bleed or bruise more easily or excessively.

Nausea and vomiting: Some types of chemotherapy can cause nausea and/or vomiting.

Appetite changes and weight changes: Some chemotherapy drugs may diminish the patient's appetite and cause weight loss, while others may boost appetite and lead to weight gain.

Constipation: Some chemotherapy drugs, as well as medicines used to manage pain, may cause digestive issues, such as constipation.

Diarrhea: When chemotherapy drugs damage the healthy cells in the intestines or cause the bowels to speed up, diarrhea may occur.

Mouth, tongue and throat problems, such as sores and pain with swallowing: If the fast-growing cells in the mouth, throat and lips are damaged by chemotherapy, the patient may experience mouth sores and infections of the gums, teeth or tongue.

Peripheral neuropathy or other nerve problems, such as numbness, tingling and pain: Chemotherapy drugs may damage the nervous system.

Skin and nail changes such as dry skin and color change: Some types of chemotherapy drugs may damage the fast-growing cells in the skin and nails.

Urine and bladder changes and kidney problems: Chemotherapy may harm cells in the kidney and bladder, causing symptoms that may include burning or pain when urinating.

Fertility problems and changes in libido and sexual function: Some types of chemotherapy drugs may damage the ovaries in women or sperm cells in men, potentially resulting in infertility. Chemotherapy’s effects on the reproductive system may also alter hormone levels, impacting sexual function and libido.

Chemotherapy prep checklist

Planning ahead for chemotherapy treatments may help make patients more comfortable, keep track of important information and limit the number of things they will have to do after treatment.

Connect with the cancer care team on questions about treatment and what to expect. Before starting chemotherapy treatment, the patient will be asked to sign a consent form. Prior to signing, it’s important that the patient fully understand details of the treatment, such as the types of drugs that will be administered, side effects and other options.

Schedule an appointment with a dentist. Seeing the dentist a month before treatment begins may help get a check on oral health and help prevent serious mouth problems from side effects. Chemotherapy may make patients more susceptible to infections, including in the mouth. A dental appointment ahead of chemotherapy treatments may help the dental care team address outstanding concerns.

Call the pharmacist. Part of planning for chemotherapy treatments includes preparing for potential side effects afterward. Call a pharmacist to have medication prescriptions filled ahead of time.

Ask a loved one to drive to and from appointments. It’s also helpful to have a loved one to take notes and help with medication instructions and other to-dos after treatment. Patients who plan to attend appointments alone should record notes to review later.

Chemotherapy at City of Hope

At City of Hope®, our medical oncologists work closely with supportive care providers who offer services to help patients manage side effects and improve quality of life. Supportive care services that may be helpful to chemotherapy patients under certain circumstances include:

Chemotherapy results

During treatment with chemotherapy, frequent doctor visits will be scheduled to determine how the treatment is going, its effect on the patient's body and how well it's doing its job and destroying cancer. During those visits, the patient may need to have several tests and exams, such as blood tests or magnetic resonance imaging (MRI) scans, to see how well the treatment is working. The doctor is the best resource to ask about the results of chemotherapy. He or she will keep the patient updated on the treatment's progress.

While it's important to pay close attention to side effects and share them with a doctor, patients shouldn't assume that their severity is associated with the treatment's success. In fact, side effects are not at all related to how well the chemotherapy is working.

Next: Learn the chemotherapy terminology.

Expert cancer care

is one call away.
appointments in as little as 24 hrs.