Chemotherapy for Cancer

Your Complete Guide to Treatment

Chemotherapy is a type of cancer treatment that uses medications to treat cancer. It may also be referred to as cytotoxic chemotherapy, as these drugs cause death to cancer cells. While an effective cancer treatment, it is a powerful one that can cause a host of side effects, from fatigue to hair loss. Though chemotherapy can still be challenging, management of many of these issues has improved dramatically in recent years.

Not all cancer medications are referred to as chemotherapy. For example, targeted drugs, immunotherapy, and hormonal therapy are different approaches to treatment that may be given as a drug.

Patients and doctor in infusion room
Isaac Lane Koval/Corbis/VCG / Getty Images

What Chemotherapy Does

A cell becomes cancerous when an accumulation of mutations (damage to DNA) causes it to reproduce and divide out of control.

Local treatments, such as surgery and radiation therapy, treat cancer where it begins. In contrast, chemotherapy—along with targeted therapies and immunotherapy—are systemic treatments that address cancer cells that are present anywhere in the body, not just the original site of the cancer.

Chemotherapy drugs work by interfering with the normal reproduction and cell division of any rapidly growing cells.

When and Why It's Used

If a cancer has spread beyond its initial location (metastasized) or if there is a chance that it has spread, systemic treatments such as chemotherapy are needed.

For example, surgery can remove a tumor in the breast, but it cannot remove any micrometastases—tumor cells that have traveled beyond the breast, but cannot yet be detected on available imaging studies. Because of this, chemotherapy is often needed to ensure that the cancer has completely been addressed; a few lingering cells can easily proliferate.

On the other hand, blood-based cancers such as leukemia are present in cells that circulate throughout the body. As such, systemic treatments are the only options that can manage these diseases.

Cancers that grow rapidly (aggressively) often respond well to chemotherapy. In contrast, slow-growing tumors, such as some types of lymphoma, do not respond as well, or at all, to this option.

Treatment Goals

Chemotherapy may be given for different reasons and with several different goals in mind. It's important to talk to your healthcare provider and understand the exact purpose of chemotherapy as part of your treatment regimen. In fact, studies have found that patients and healthcare providers often differ in their understanding of these goals.

The purpose of chemotherapy may be:

  • Curative therapy: With blood-related cancers, chemotherapy is often given with the intent of curing the cancer. With curative therapy, your treatment may be broken down into induction chemotherapy, which is the initial step in treatment, followed by consolidation chemotherapy, which follows.
  • Adjuvant chemotherapy: Chemotherapy may be given as an adjuvant treatment—that is, along with other treatments for cancer. A common example of this is when chemotherapy is used for people with early-stage breast cancer—cancer that may or may not have spread to lymph nodes, but has not spread to other organs in the body. In this example, chemotherapy is used as a method of eradicating any micrometastases.
  • Neoadjuvant chemotherapy: Chemotherapy may be given before surgery to shrink a tumor enough so that surgery is possible. For example, neoadjuvant chemotherapy may be given to someone who has an inoperable lung cancer in order to decrease the size of the cancer so that surgery can be performed.
  • To extend life: Chemotherapy is often used with solid tumors in order to increase life expectancy. With a recurrent cancer or a cancer that has metastasized, a cure is not usually possible, but chemotherapy may increase overall survival or the time until a tumor progresses (progression-free survival).
  • Maintenance chemotherapy: After initial treatment with chemotherapy, maintenance chemotherapy may sometimes be given either to help maintain remission of cancer or to prevent a cancer that is present from growing. With maintenance therapies, the doses of drugs used are often less than those given during initial chemotherapy.
  • Palliative therapy: Chemotherapy may also be given as a palliative treatment (palliative chemotherapy). In this setting, chemotherapy is used to reduce the symptoms caused by cancer, but not with an intent to cure the cancer. This is also sometimes referred to as salvage chemotherapy.

Why Doesn't Chemotherapy Always Cure Cancer?

Since chemotherapy can often effectively decrease the size of a tumor, many wonder why it doesn't usually cure cancers (solid tumors) that have spread. The problem is that cancer cells find ways to outsmart the drugs after a period of time. Oncologists refer to this as a tumor developing resistance. This is the reason why a different combination of chemotherapy drugs (second-line treatment) is often used if a cancer recurs or grows while on chemotherapy.

Chemo Drug Categories

There are several types of chemotherapy drugs, which vary both in how they work (mechanisms) and where they work (what part of the cell cycle). Some drugs work on one of the four primary phases of cell division, whereas others—termed phase non-specific drugs—may work at multiple points.

Some of these classes of drugs include:

  • Alkylating agents: This is the most commonly used class of chemotherapy drug. They are non-specific drugs that directly damage DNA and are used to treat a wide variety of cancers. Examples include Cytoxan (cyclophosphamide) and Myleran (busulfan).
  • Antimetabolites: Simplistically, these drugs work by pretending they are nutrition sources for the cell. Cancer cells take up these drugs instead of nutrients and essentially starve to death. Examples include Navelbine (vinorelbine), VP-16 (etoposide), and Gemzar (gemcitabine).
  • Plant alkaloids: This class includes drugs obtained from plant sources. Examples include Cosmegen (dactinomycin) and Mutamycin (mitomycin).
  • Antitumor antibiotics: Antitumor antibiotics differ from the types of antibiotics used to treat bacterial infections. These drugs work by preventing cancer cells from reproducing (and hence, keep tumors from growing). Examples include Adriamycin (doxorubicin), Cerubidine (daunorubicin), mitoxantrone, and Bleo 15K (bleomycin).

Combination Chemotherapy

A combination of different chemotherapy drugs, rather than a single drug alone, is usually used to treat cancer. There are several reasons for combination chemotherapy.

Cancer cells in a tumor are not all in the same place in the process of growth. Using drugs that affect the cell cycle at different points in multiplication and cell division increases the chance that as many cancer cells as possible will be treated.

Using a combination of medications may also allow healthcare providers to use lower doses of several agents, rather than a higher dose of a single agent, thereby decreasing the toxicity of the therapy (and related side effects).

Acronyms are often used to describe chemotherapy protocols. For example, BEACOPP is a seven-drug regimen used in the treatment of Hodgkin's lymphoma.

How Chemo Is Administered

Chemotherapy may be given in several different ways depending on the particular drug. Methods include:

  • Intravenous injection (IV): Many chemotherapy drugs are given intravenously. Most of these drugs are unable to be given orally as they would be broken down by digestive enzymes, or would be too toxic to the lining of the digestive tract. IV drugs may be given via either a peripheral IV or a central line (see choices below).
  • Intramuscular injection (IM): IM injections deliver the drug into a muscle, like a tetanus shot.
  • Subcutaneous injection (SubQ): SubQ injections are given with a small needle just beneath the skin, like a TB test.
  • Intrathecal injection: Intrathecal chemotherapy is an approach in which chemotherapy drugs are delivered directly into the cerebrospinal fluid (CSF) that bathes the brain and spinal cord. Many cancer drugs do not cross the blood-brain barrier—a membrane surrounding the brain that limits its access to toxins. In order to treat cancer cells in the brain, a needle is inserted directly into this space in a procedure similar to a spinal tap. Sometimes—similar to a central line in IV therapy—a reservoir is placed under the scalp (an Ommaya reservoir) to allow repeated intrathecal injections. Intrathecal chemotherapy may be used either to treat cancer that has spread to the CSF or to prevent cancer from spreading there.
  • Intraperitoneal injection: With intraperitoneal chemotherapy, chemotherapy agents are injected directly into the peritoneal cavity, the cavity that houses many of the abdominal organs.
  • Oral therapy: Some medications may be given as a pill, capsule, or liquid.

Conjugated monoclonal antibody therapy is a newer and novel method of delivering chemotherapy drugs. A type of immunotherapy, it consists of a monoclonal antibody, which serves to find and attach itself to specific cancer cells, as well as the chemotherapy drug, which is delivered directly to the cancer cell (and, thus, is often called "the payload").

IV Methods

One question you may face if you are having IV chemotherapy is whether to have these treatments through a peripheral IV or a central venous catheter (CVC).

With a peripheral IV, your chemotherapy nurse will place an IV in your arm at the start of each infusion and remove it at the end. A central venous catheter is placed prior to beginning chemotherapy and is often left in place through the duration of treatments.

There are risks and benefits of each of these methods, though sometimes a central line is mandatory (for example, with chemotherapy drugs that are very irritating to veins).

There are three main types of central lines:

A chemotherapy port, or port-o-cath, is a small plastic or metal receptacle that is placed underneath your skin, usually on your chest. Attached to this is a catheter that is threaded into a large vein near the top of your heart. These are inserted in the operating room under sterile conditions preferably a week or so before your first infusion.

A port can spare you the repeated needle sticks of a peripheral IV and can also be used to draw blood and give transfusions.

A PICC line is inserted in a vein deep in your arm and can usually be used for up to six months.

If your veins are damaged from chemotherapy, or too small for a PICC line to be placed, a tunneled CVC is a third option for some people. In this procedure, a catheter is tunneled under the skin, usually on your chest, and the catheter is threaded into a large vein as with a port or PICC line.

Treatment Duration and Frequency

Chemotherapy is usually given over the course of several sessions, separated by a period of time (often two to three weeks). Since chemotherapy treats cells that are in the process of cell division, and cancer cells are all in different states of resting and dividing, repeated cycles allow a greater chance to treat as many cancer cells as possible.

The amount of time between sessions will vary depending on the drugs, but is often scheduled at a time when your blood count is expected to have returned to normal.

You will likely spend a significant amount of time sitting during your infusion sessions. You will need comfort items and things that will help prevent boredom.

Side Effects of Chemotherapy

Some normal cells in your body divide rapidly, just like cancer cells, they can also be effected by chemotherapy. Examples include cells of the hair follicles, bone marrow, and digestive tract, which accounts for the well-known chemo side effects of hair loss, bone marrow suppression, and nausea.

Many people are frightened about chemotherapy because of years-past stories they have heard about such side effects. While these issues still occur, improvements in chemotherapy and side effect management have improved the experience for patients. There are also several things you can do to add to your comfort at this time.

Keep in mind that everyone is different and responds to chemotherapy in a different way. Some people may have several of these side effects, while others may have none at all. The particular side effects you might expect will depend on the specific medications you receive.

Some of the most chemotherapy side effects common include:


Fatigue is the most common side effect of chemotherapy, affecting nearly everyone who receives these treatments. Unfortunately, this kind of fatigue isn't the type of tiredness that responds to a cup of coffee or a good night of sleep.

There are a number of things that may help you cope with cancer fatigue, but the most important one is to allow yourself the extra time you need for rest. The best "treatments" for this side effect are to reach out to family and friends and allow them to help you. The saying "it takes a village" is nowhere as fitting as in the setting of chemotherapy.

Nausea and Vomiting

Nausea and vomiting are perhaps the most feared side effects of chemotherapy, but both prevention and treatment of these symptoms have improved dramatically in recent years. Anti-nausea drugs (antiemetics) are frequently given right along with many of the chemotherapy drugs to prevent nausea.

Both medications and lifestyle factors can help with chemotherapy-induced nausea and vomiting. Taking a few moments to consider the food you eat is important, and experts are learning more and more about the importance of good nutrition during cancer care.

While many people have found using ginger and acupressure for chemotherapy-related nausea helpful, these alternative approaches should be used along with, rather than instead of, conventional anti-nausea treatments for the best results.

Once nausea has developed, it can be much harder to play "catch up" than if the symptom is addressed right away.

Hair Loss

Hair loss is common with chemotherapy, and though it's not dangerous to your physical health, it can be very distressing emotionally.

Not all chemotherapy drugs cause hair loss, but what surprises many people is that those that cause hair loss usually cause more than the loss of hair on your head. From the top of your head, to your eyebrows and eyelashes, to pubic hair, preparing for hair loss on chemotherapy may help you cope a little easier with what's to come.

Some people find it helpful to go wig and scarf shopping before they start treatment. Others find that "reframing" can add a little lightness to this stressful time. Though having the "benefit" of not having to shave your face or legs is stretching it a bit, thinking this way has helped many people facing this common side effect.

Hair loss commonly begins two to three weeks after your first treatment, with regrowth occurring rapidly after your final treatment. Hair loss may persist if you receive radiation to your head, but permanent hair loss is rare with chemotherapy alone.

Researchers have looked into methods for preventing hair loss from chemotherapy with some mild success. The use of scalp cooling has been partially effective in some studies, though this can be very uncomfortable and carries a theoretical risk of reducing the effectiveness of treatment.

Bone Marrow Suppression

Suppression of the bone marrow is one of the more dangerous side effects of chemotherapy, but management of it—especially the risk of infections due to a low white blood cell count—has improved substantially in recent years.

All of your blood cells (white blood cells, red blood cells, and platelets) are formed from stem cells in the bone marrow. Since these are very rapidly dividing cells, all of them can be reduced by chemotherapy. Your oncologist will check a complete blood count (CBC) prior to each chemotherapy infusion and monitor your levels closely.

Mouth Sores

Around 30% to 40% of people will experience chemotherapy-induced mouth sores during treatment, though some medications are more likely than others to cause this symptom. If you are receiving drugs likely to cause mouth sores, your chemotherapy nurse may encourage you to suck on an ice pop or ice chips while the drug is infused.

These sores can be uncomfortable on their own, but can also predispose you to secondary infections such as oral thrush.

A few dietary precautions can make a big difference in your comfort. Tips include avoiding citrus fruits, spicy and salty foods, and foods at extreme temperatures, and minimizing choices with sharp edges (like cracker)s.

You may hear cancer survivors rave about "magic mouthwash" for mouth sores, but talk to your oncologist before using any preparation, prescription or otherwise.

Taste Changes

Taste changes, often referred to as "metal mouth," occur for half of people undergoing chemotherapy. This symptom is most often just a nuisance, but you may still want to take steps to avoid it.

Many people find these taste changes less bothersome if they add a touch of flavor to foods by marinating meats and using a variety of sauces (adding liquids to foods can also help with mouth sores). Sucking on mints or chewing gum and switching to plastic utensils may also be helpful.

Peripheral Neuropathy

Tingling and pain in a stocking-glove distribution (hands and feet) are common symptoms related to chemotherapy-induced peripheral neuropathy. This affects roughly a third of people receiving chemotherapy.

Some drugs, most notably so-called platinum agents, are more likely to cause this side effect than others. Your nerves are lined with a substance called myelin that acts is a similar way to the outer covering of an electrical cord. It's thought that these drugs somehow damage myelin and, in doing so, disrupt the normal processing of nerve signals.

Unlike many of the symptoms associated with chemotherapy, neuropathy often persists well after chemotherapy has been completed, and can—at times—be permanent.

Research into glutamine and other methods that might prevent neuropathy from occurring in the first place is ongoing. Talk to your healthcare provider about these options before beginning chemotherapy.

Bowel Changes

Chemotherapy drugs can cause bowel changes ranging from constipation to diarrhea, depending on the drug. Constipation is common with some of the drugs used to prevent nausea, and your healthcare provider may recommend measures for preventing constipation during chemotherapy, such as a stool softener, laxative, or both.

Diarrhea can quickly become a problem for people on chemotherapy, especially as it contributes to dehydration. Certain foods can help, but make sure to talk to your practitioner promptly if you have this issue.

Sun Sensitivity

Many chemotherapy drugs increase your chance of getting a sunburn when you go out in the sun, something referred to as chemotherapy-induced phototoxicity.

Ask your healthcare provider if the drugs you will receive place you at risk and what precautions you should take.

Note: Sunscreen alone may not be effective and may irritate your skin, especially if you are also receiving radiation therapy.


The term chemobrain has been coined to describe the cognitive effects some people experience during and after chemotherapy. Symptoms ranging from increased forgetfulness to difficulty with multitasking can be frustrating, and it can help for family members to be aware of this potential side effect.

Some people find that keeping their brain active with exercises such as crossword puzzles, sudoku, or whatever "brain teasers" they enjoy can be helpful in the days and weeks following treatments.

Long-Term Complications

With all cancer treatments, the benefits of treatment need to be weighed against the possible risks. While eradicating or managing your cancer is you primary concern, it's important to be aware of how chemotherapy might affect you months or even years after completion of cancer treatment.

As with the short-term side effects, the odds that you will experience these issues depends on the particular chemotherapy drugs you receive.

Heart Disease

Some chemotherapy drugs, especially drugs such as Adriamycin (doxorubicin), can cause heart damage. The type of damage may range from heart failure to valve problems to coronary artery disease.

If you are receiving any of these drugs, your healthcare provider may recommend a heart test before you begin treatment. Radiation therapy to the chest may also increase the risk of heart-related problems.


Many chemotherapy drugs result in infertility after treatment. If there is a chance you would like to conceive after chemotherapy, options such as freezing sperm or freezing embryos have been used successfully by many people. Make sure to have this discussion before starting treatment.

Peripheral Neuropathy

The tingling, numbness, and pain in your feet and hands caused by some chemotherapy agents may persist for many months, or may even be permanent. As noted, research is being done to look for ways to not only treat this side effect but prevent it from occurring altogether.

Secondary Cancers

Since some chemotherapy drugs work by causing DNA damage in cells, they may not only treat cancer but predispose someone to developing a secondary cancer as well.

An example of this is the development of leukemia in people who have been treated with Cytoxan (cyclophosphamide), a drug commonly used in breast cancer treatment. These cancers often occur five to 10 years or more after chemotherapy has been completed.

Other possible late effects may include symptoms ranging from hearing loss or cataracts to lung fibrosis. Though the risk of these adverse reactions usually pales in comparison to the benefit of treatment, take a moment to talk with your healthcare provider about side effects that may be unique to your particular chemotherapy regimen.

Questions to Ask Your Healthcare Provider

A cancer diagnosis thrusts you into a world of details—a lot of which are not always easy to understand. As you work to get a better hold on what chemotherapy may mean for you before, during, and after your course, you may find it helpful to ask your healthcare provider these questions.

About the therapy itself:

  • What is the purpose of the chemotherapy I will be receiving? (E.g., is the goal to cure your cancer or reduce symptoms?)
  • What specific chemotherapy drugs are being recommended? How will these drugs be given?
  • If drugs are to be administered intravenously, do you recommend a port or a PICC line, or is a peripheral IV OK?
  • Are there any clinical trials available that may be more effective than the regimen that's recommended?
  • How (and when) will you know if the chemotherapy drugs are working?
  • What is your "plan B" if chemotherapy is not effective?

About side effects and complications:

  • What are the more common side effects of this treatment? What should prompt me to call you right away?
  • When can I expect side effects to begin and end, and what can be done to manage them?
  • Will I need to take medications after I go home? (e.g., laxatives to prevent constipation)
  • What alternative or complementary therapies may help ease the symptoms of chemotherapy? Are these available at your cancer center?
  • How often will my blood counts be checked? What should the numbers be before my next session? What will happen if my counts are too low?
  • Are there any common long-term complications of this treatment? Can anything be done to lower the risk?
  • Premenopausal women: Do I need to use birth control?
  • What measures can I take to preserve my ability to have children? (If desired.)
  • Will I need to take any special precautions? (E.g., stay away from people who are sick)
  • Should I take any vitamin or nutritional supplements during chemotherapy? (Chemotherapy could predispose you to vitamin deficiencies, but some vitamin and mineral supplements may interfere with chemotherapy.)
  • Do I need any immunizations because I'm undergoing chemo?

Be sure to ask about important logistical and practical matters as well, such as:

  • How much will the treatment cost?
  • Where will chemotherapy treatments take place?
  • How often will I have infusions? How many total sessions will be needed?
  • How long will each session last?
  • Is it OK to go alone, or do I need to bring someone with me?
  • How will chemo affect my day-to-day life, ability to work, and ability to care for my children? Will I need to make significant adjustments?
  • If I might lose my hair, can you write me a prescription for a "hair prosthesis" or a "cranial prosthesis" so that I can get a wig covered by my health insurance?
  • Who should I call if I have any concerns day or night?

Everyday Life During Treatment

Most people lead busy lives before a diagnosis of cancer. Learning you will need chemotherapy may have you wondering how you will ever manage your "normal" commitments and obligations along with your treatment. Take a moment to consider these matters and think about what help you will need to keep your life running smoothly.

For example, do you need rides to your cancer center? Do you need help with childcare? Choose a good friend or two who can be your "coordinators" when it comes to errands and communicating to others. These people can help organize the efforts of friends who have offered to help and act as spokespersons when you really don't want to answer the phone.

Many people also start a site on Caring Bridge or a similar site where they can share updates on how treatment is going. These sites can also be a tremendous source of encouragement and allows friends to send their love without worrying about disturbing you.

Sites such as Lotsa Helping Hands can be invaluable in organizing tasks among those who have volunteered to help. Whether it is preparing a meal to deliver to you or helping with housework, people can sign up for dates and times to offer their assistance.

15 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Schillert A, Trumpp A, Sprick MR. Label retaining cells in cancer--the dormant root of evil? Cancer Lett. 2013;341(1):73-9. doi:10.1016/j.canlet.2013.04.019

  2. Weeks JC, Catalano PJ, Cronin A, et al. Patients' expectations about effects of chemotherapy for advanced cancer. N Engl J Med. 2012;367(17):1616-25. doi:10.1056/NEJMoa1204410

  3. Pabla N, Dong Z. Curtailing side effects in chemotherapy: a tale of PKCδ in cisplatin treatment. Oncotarget. 2012;3(1):107-11. doi:10.18632/oncotarget.439

  4. Sreerama L. Alkylating Agents. In: Schwab M, editor. Encyclopedia of Cancer. Berlin, Heidelberg: Springer; 2011. doi:10.1007/978-3-642-16483-5_182

  5. Yardley DA. Drug resistance and the role of combination chemotherapy in improving patient outcomes. Int J Breast Cancer. 2013;2013:137414. doi:10.1155/2013/137414

  6. Modjtahedi H, Ali S, Essapen S. Therapeutic application of monoclonal antibodies in cancer: advances and challenges. Br Med Bull. 2012;104:41-59. doi:10.1093/bmb/lds032

  7. Gonzalez R, Cassaro S. Percutaneous Central Catheter (PICC). StatPearls Publishing.

  8. Trüeb RM. Chemotherapy-induced alopecia. Semin Cutan Med Surg. 2009;28(1):11-4. doi:10.1016/j.sder.2008.12.001

  9. Hofman M, Ryan JL, Figueroa-moseley CD, Jean-pierre P, Morrow GR. Cancer-related fatigue: the scale of the problem. Oncologist. 2007;12 Suppl 1:4-10. doi:10.1634/theoncologist.12-S1-4

  10. Lundqvist EÅ, Fujiwara K, Seoud M. Principles of chemotherapy. Int J Gynaecol Obstet. 2015;131 Suppl 2:S146-9. doi:10.1016/j.ijgo.2015.06.011

  11. Joaquín-Mingorance M, Arbinaga F, Carmona-Márquez J, Bayo-Calero J. Coping strategies and self-esteem in women with breast cancer. Anales de Psicología. 2019;35(2). doi:10.6018/analesps.35.2.336941

  12. Nangia J, Wang T, Osborne C, et al. Effect of a Scalp Cooling Device on Alopecia in Women Undergoing Chemotherapy for Breast Cancer: The SCALP Randomized Clinical Trial. JAMA. 2017;317(6):596-605. doi:10.1001/jama.2016.20939

  13. Chaveli-lópez B. Oral toxicity produced by chemotherapy: A systematic review. J Clin Exp Dent. 2014;6(1):e81-90. doi:10.4317/jced.51337

  14. Apisarnthanarax N, Duvic MM. Photosensitivity Reactions. In: Kufe DW, Pollock RE, Weichselbaum RR, et al, editors. Holland-Frei Cancer Medicine. 6th Edition. Hamilton (ON): BC Decker; 2003.

  15. Brower V. Tracking chemotherapy's effects on secondary cancers. J Natl Cancer Inst. 2013;105(19):1421-2. doi:10.1093/jnci/djt273

Additional Reading
  • American Society of Clinical Oncology. Cancer.Net. Understanding Chemotherapy.

  • Longo, D. L. Harrison's Principles of Internal Medicine. 2017. New York: McGraw-Hill.

  • National Cancer Institute. SEER Training Manual. Types of Chemotherapy Drugs.

  • Niederhuber, J., Armitage, J., Doroshow, J., Kastan, M., and J. Tepper. Abeloff's Clinical Oncology: 6th Edition. 2019. Philadelphia: Churchill Livingstone/Elsevier.

By Lynne Eldridge, MD
 Lynne Eldrige, MD, is a lung cancer physician, patient advocate, and award-winning author of "Avoiding Cancer One Day at a Time."