What is chemotherapy?

Chemotherapy, also called chemo, is a cancer treatment that uses drugs to prevent cancerous cells from growing and dividing. There is a wide range of chemotherapy medications that are used to treat cancer. Their effectiveness depends on the extent of cancer being treated and your body’s response to the drugs.

Chemotherapy targets cancerous cells that grow and divide quickly. In many cases, chemotherapy is not targeted to the tumor but affects the entire body - which can lead to adverse side effects like hair loss. Some types of chemotherapy can be targeted directly at the growing tumor.

Who is a candidate for chemotherapy?

Your Mercy Health oncology team will evaluate your case to determine the most effective treatment plan for you. Depending on the type of cancer you have and the stage your cancer, the goal of treatment may be different:

  • Some patients may be cured from their cancer with chemotherapy treatment. In these patients, the cancer cells may be destroyed so the doctor can no longer detect them in the body.
  • Chemotherapy may be used to slow the growth or spread of cancer to other body parts.
  • Some patients may need chemotherapy to relieve pain or shrink tumors. In these patients, chemotherapy may not be able to completely eliminate the cancer cells.

When is chemotherapy used?

Chemotherapy can be used in combination with surgery, radiation therapy or as a stand-alone treatment. Chemotherapy is used in the following ways:

  • Neoadjuvant chemotherapy — when used before radiation therapy, the goal is to shrink the tumor.
  • Adjuvant chemotherapy — used to destroy any remaining cells that could not be eliminated during surgery or radiation therapy.
  • Used in combination with radiation or surgery to make the total therapy more effective.
  • Used to kill any new cells that return after the initial treatment

What are side effects associated with chemotherapy?

Although side effects of chemotherapy can be severe, typically the benefits outweigh the risks. Side effects could occur because the medication damages healthy tissues. Healthy cells that can be impacted include:

  • Hair cells
  • Mouth, digestive tract and reproductive system cells
  • Bone marrow cells that form blood

Your Mercy Health cancer team will closely evaluate your case to dose your chemo high enough to kill the cancerous cells, while minimizing the side effects associated with the medications.

Common side effects of chemotherapy include:

  • Loss of hair
  • Bruising
  • Bleeding
  • Infection at the IV insertion site
  • Fatigue
  • Vomiting or nausea
  • Diarrhea or constipation
  • Sores in mouth
  • Nerve pain
  • Weight loss
  • Mood changes
  • Skin changes
  • Sexual dysfunction

What to expect during chemotherapy?

Chemotherapy is an invasive treatment with severe side effects. Patients should discuss all benefits and risks associated with the treatment before the first treatment.

Your Mercy Health cancer team will determine the frequency and duration of your chemotherapy treatments. Depending on your stage of cancer, some patients may have a single dose of chemotherapy, while others may need treatment for a few weeks.

Depending on your overall health and response to the medication, you may need treatment breaks to allow your body to heal after each treatment session.

Chemotherapy is a physically and emotionally draining treatment. Many patients need counseling to deal with the toll it takes.

Testing during treatment

Your Mercy Health cancer team will take frequent blood tests during treatment to ensure you are responding and recovering from treatment. If blood tests come back with abnormal results, you may need to take a break from chemotherapy treatment until your body recovers.

How is chemotherapy administered?

Chemotherapy can be administered via an oral pill (or liquid), intravenously, injected, or rubbed onto external cancer sites (skin cancer).

  • Orally — you can take a tablet, capsule or liquid medication. In many cases, you can take the medication at home but will need regular visits with your doctors to determine how you are responding to treatment.
  • IV chemotherapy — intravenous chemotherapy is medication that is delivered directly into a vein; delivery can be through a catheter, needle, port or pump.
  • Injected into a muscle — typically in the arm, thigh, hip, leg or stomach
  • Topically — rubbed into a tumor on the skin
  • Intra-arterial (IA) — drugs fed directly into an artery that is feeding the cancerous growth
  • Intraperitoneal (IP) — drugs are delivered into the cavity that contains the liver, intestines, stomach and ovaries.

How effective is chemotherapy?

Chemotherapy is an effective treatment for many patients. How you will respond to the therapy depends on your age, overall health, existing medical conditions as well as the type and severity of your cancer.

Some patients can be cured with chemotherapy alone while others will need combination treatment for the most favorable results.


During and after chemotherapy, you will need to be under the close supervision of your cancer care team. If you are not responding or have abnormal tests, your plan may be modified.

If you catch your cancer in an early stage, you are more likely to have a successful result from treatment.

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