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Miquel Llonch/Stocksy United

Chemotherapy, often referred to simply as chemo, is a treatment that uses drugs to attack cancer cells. There are over 100 drugs that may be used during chemotherapy treatment. Often, more than one drug is administered simultaneously.

Chemotherapy drugs enter the blood stream and travel throughout the body. Some chemo drugs can even cross the blood-brain barrier. This makes chemotherapy different from cancer treatments such as surgery and radiation, which target cancer cells in a specific location.

Chemotherapy may be recommended at various stages of cancer treatment. Not every person will go through every stage. And chemotherapy treatment is not right for all forms of cancer.

Your doctor may recommend chemotherapy for these purposes:

  • Neoadjuvant (induction) therapy is used to shrink a tumor or tumors prior to surgery or radiation.
  • Adjuvant therapy is used after surgery or radiation to lower the risk of cancer recurrence.
  • Curative therapy is used as the sole treatment used to treat cancer.
  • Palliative therapy is used to shrink tumors and reduce symptoms, but it’s not as a curative.

Chemotherapy is often categorized by the types of drugs used for treatment.

This table illustrates some common chemotherapy types, along with some of the drugs used for each. Drugs may belong to more than one group. The table also lists some cancers that may be treated with each type of chemotherapy.

Types of chemotherapySome drugs used in treatmentExamples of cancers treated
Alkylating agents: keep cancer cells from reproducing and spreading by damaging their DNAaltretamine
busulfan
cyclophosphamide
temozolomide
breast
Hodgkin’s disease
leukemia
lung
lymphoma
multiple myeloma
ovarian
sarcoma
Antimetabolites: interfere with the normal division of cells and stops DNA from reproducingazacitidine
clofarabine
hydroxyurea methotrexate
breast
intestinal tract
leukemia
ovarian
Anti-tumor antibiotics (anti-cancer, antineoplastic antibiotics): block cell growth by altering DNA inside cancer cellsbleomycin
dactinomycin
doxorubicin
valrubicin
breast
liver
lung
malignant lymphoma
Topoisomerase inhibitors (plant alkaloids): kill cancer cells by blocking the enzymes that break and rejoin DNA strandsetoposide
irinotecan
teniposide
topotecan
colorectal
gastrointestinal
lung
ovarian
pancreatic
Mitotic inhibitors (plant alkaloids): block cell growth by stopping cell divisioncabazitaxel
docetaxel
paclitaxel
vinblastine
vinorelbine
breast
endometrial
leukemia
lung
lymphoma
myeloma
ovarian

Chemotherapy drugs work by killing cancer cells or by stopping them from dividing. The class of drug determines how this task is done.

Chemotherapy drugs target cancer cells at various points in their maturation. Like normal cells, cancer cells go through various stages of growth before they become fully mature. This is known as the cell cycle.

Alkylating agents against cancer cells

Some drugs, such as alkylating agents, directly affect each cancer cell’s DNA. For example, the drug may cause DNA strands to break, preventing cell division. Many alkylating agents can be administered at any point during the cell cycle.

Antimetabolites against cancer cells

Antimetabolites replace and mimic the nutrients that cancer cells need to grow, which starves them to death. This type of drug is most effective when given during the S-phase (synthesis of new DNA) of the cell cycle.

Anti-tumor antibiotics against cancer cells

Antitumor antibiotics uncoil cancer cell DNA strands. This stops them from reproducing. This type of drug can be given at any point during the cell cycle.

Alkaloids against cancer cells

Plant alkaloids block cell division. They may be given at any time during the cell cycle but may be most effective during specific stages of cell development.

Chemotherapy drugs target fast-growing cells. Cancer cells grow quickly and erratically, making them prime targets for this type of aggressive drug treatment.

How does chemotherapy affect healthy cells?

Healthy, normal cells that are fast growing are also affected by chemotherapy drugs. These include:

  • hair follicle cells
  • skin cells
  • blood cells
  • cells inside the mouth
  • stomach and bowel cells

The effect of chemo on healthy cells can cause many side effects. Various factors may affect the intensity of these side effects, including:

  • health conditions you have, such as high blood pressure, frailty, and heart disease
  • your age
  • the type of chemo and amount of medication administered
  • length of treatment

The drugs used in chemotherapy can be administered in several ways.

Chemo for systemic treatment

If the drugs are meant to work through your entire system, you may get chemo:

  • Intravenously, via infusion into a vein. This may be done in a hospital or surgical center setting. In some instances, an infusion nurse may give you infusion treatments at home.
  • Via an injection. Injections are typically given in medical settings but may also be administered at home.
  • Orally, in liquid or pill form. Oral chemo treatment may be administered at home.
  • Topically, in cream or lotion form. This type of chemo is typically used to target skin cancer and can be done at home.

Chemo by localized delivery

Chemotherapy drugs may also be used to target tumors in a specific area of the body. These localized delivery systems may use slow-dissolving disks containing chemo drugs or other mediums of delivery:

  • Intra-arterial. Drugs are injected into a single, specific artery that supplies blood to the tumor.
  • Intracavitary. Drugs are placed directly into a body cavity, such as the abdomen or bladder.
  • Intrathecal. Drugs are placed between the spinal cord and brain.
  • Intraperitoneal. Drugs are placed via a catheter into the peritoneal cavity of the abdomen.

Does how my chemo is given impact side effects?

It can. In some instances, the way you receive chemo may impact the side effects you experience.

For example, oral chemotherapy may cause milder but more prolonged side effects.

Targeted chemotherapy delivery systems may cause localized side effects at the tumor site, such as swelling or bleeding.

Cancer treatments are not one-size-fits-all. The chemotherapy plan that is best for you will be one that treats cancer effectively and gives you time to recover between treatments. Limiting the intensity and duration of side effects is part of that goal.

Your doctor will work out a chemotherapy plan with you, based on multiple factors. These include:

  • the type of cancer
  • the intent of the treatment
  • where the tumor is located
  • level of metastasis (spread)
  • your overall health and strength
  • the drugs being administered

A course of chemotherapy typically lasts from 3 to 6 months but that is just a starting estimate. Your treatment plan may require more or fewer rounds of treatment over longer periods of time.

Treatment cycles typically consist of four to six rounds of chemo. These may be given on a daily, weekly, or monthly basis. You will then have a resting period before the next round of treatments begin.

Individual chemotherapy treatments vary in length from a few minutes to several hours.

Continuous infusion treatments can last for several days. These are typically started in a hospital or outpatient chemotherapy setting and continued at home.

The spacing out of treatments gives your body time to heal. It also helps ensure that cancer cells are targeted at the optimum time during the cell cycle.

You and your doctor will want to know if your chemo treatment plan is working. To gauge this, you will continue to be monitored during treatment.

You will see your doctor for scans and testing, usually right before and right after treatments. This will help determine if your treatment plan is effective.

Tests to anticipate include:

  • physical exam
  • talking about medical history and history of symptoms
  • blood tests
  • MRI (magnetic resonance imaging)
  • CT scan (computerized tomography
  • biomarker (tumor marker) testing

It’s hard to gauge chemo’s effectiveness without testing. You may find yourself looking for clues and may become nervous if you don’t feel or see improvement or if you’re feeling worse from side effects of the chemo.

During treatment, you may see less visible lymph node swelling. You may also feel less pain or have more energy. If these changes aren’t apparent to you, don’t worry. It doesn’t mean that chemotherapy isn’t working. Testing is the only way to know for sure.

Try to be patient and talk with your doctor about what to expect. Your chemotherapy plan may be changed if it isn’t providing the results you hoped for.

Seeing your doctor regularly will also give you the opportunity to discuss any side effects you’re having and get medications to curb them.

Finding out you need chemo can be challenging. Looking for the best treatment centers and working through health insurance information and processes can be a lot to deal with, on top of a cancer diagnosis.

Chemotherapy may be administered in an outpatient chemotherapy unit, in a doctor’s office or hospital, or at home if you’re receiving oral chemotherapy. Keep in mind that your out-of-pocket costs may vary, based on where you have chemo. Talk with your insurance provider to find out what costs you can expect.

Your doctor may be a good initial source for referrals and information. If you’re already seeing a cancer specialist such as an oncologist, working with their billing department manager can be helpful in navigating health insurance eligibility issues and claims.

The American Cancer Society is a another resource for locating a specialist and a treatment center.

You can find an NCI-designated cancer center through the National Cancer Institute.

The National Cancer Institute also publishes a resource list of organizations that offer support services, including emotional, practical, and financial support.

There are several different types of cancer treatments. Not every treatment is appropriate for every type or stage of cancer.

When weighing one treatment against the other, try to avoid social networking sites that may surface highly opinionated or one-sided content about chemotherapy and other treatments.

Look for health content publishers and sites that work with and speak to licensed health professionals and provide current research. Talk with your doctor and nurse. Getting a second or third opinion from medical professionals you trust also makes sense.

Treatment options for cancer include:

Chemotherapy is a type of cancer treatment that uses drugs to kill cancer cells. Chemo may be done on its own or in conjunction with other treatments.

In some instances, chemo may be curative. In others, it may help reduce pain and make you more comfortable. It may also make surgery and radiation more effective.

Since it impacts healthy cells as well as cancerous ones, chemotherapy can cause side effects that can be intense. Your doctor may be able to prescribe medications that eliminate or reduce some side effects from chemotherapy.