Chemotherapy: How It Works and How You'll Feel

Medically Reviewed by Sabrina Felson, MD on March 24, 2023
5 min read

Also called “chemo,” it’s a way to treat cancer that uses drugs to kill cancer cells.

It targets cells that grow and divide quickly, as cancer cells do. Unlike radiation or surgery, which target specific areas, chemo can work throughout your body. But it can also affect some fast-growing healthy cells, like those of the skin, hair, intestines, and bone marrow. That’s what causes some of the side effects from the treatment.

It depends on the kind of cancer you have and how far along it is.

  • Cure: In some cases, the treatment can destroy cancer cells to the point that your doctor can no longer detect them in your body. After that, the best outcome is that they never grow back again, but that doesn’t always happen.
  • Control: In some cases, it may only be able to keep cancer from spreading to other parts of your body or slow the growth of cancer tumors.
  • Ease symptoms: In some cases, chemotherapy can’t cure or control the spread of cancer and is simply used to shrink tumors that cause pain or pressure. These tumors often continue to grow back.

 

Sometimes, it treats cancer by itself, but more often it’s used in combination with:

  • Surgery: A doctor removes cancerous tumors or tissue, or organs contaminated with cancerous cells.
  • Radiation therapy: A doctor uses invisible radioactive particles to kill cancer cells. It may be delivered by a special machine that bombards parts of your body from the outside, or by putting radioactive material on, near, and even inside your body.
  • Biological therapy: Living material in the form of bacteria, vaccines, or antibodies are carefully introduced to kill cancer cells.

Chemotherapy may be used to:

  • Shrink a tumor before radiation therapy or surgery -- called neoadjuvant chemotherapy
  • Destroy any remaining cancer cells after surgery or radiation therapy -- called adjuvant chemotherapy
  • Make other therapies (biological or radiation) more effective
  • Destroy cancer cells that return or spread to other parts of your body

That depends on:

  • The type of cancer you have
  • How far along it is
  • The goal of treatment: cure, control growth, or ease pain
  • The type of chemotherapy
  • The way your body responds to the treatment

You may have chemotherapy in “cycles,” which means a period of treatment and then a period of rest. For example, a 4-week cycle may be 1 week of treatment and then 3 weeks of rest. The rest allows your body to make new healthy cells. Once a cycle has been planned out, it’s better not to skip a treatment, but your doctor may suggest it if side effects are serious. Then your medical team will likely plan a new cycle to help you get back on track.

  • Injection: The drugs are delivered with a shot directly into muscle in your hip, thigh, or arm, or in the fatty part of your arm, leg, or stomach, just beneath the skin.
  • Intra-arterial (IA): The drugs go directly into the artery that is feeding the cancer, through a needle, or soft, thin tube (catheter).
  • Intraperitoneal (IP): The drugs are delivered to the peritoneal cavity, which contains organs such as your liver, intestines, stomach, and ovaries. It is done during surgery or through a tube with a special port that is put in by your doctor.
  • Intrathecal (IT) chemotherapy: Medicine is injected into the cerebrospinal fluid (CSF), which is found in the area surrounding the spinal cord and the brain.
  • Intravenous (IV): The chemotherapy goes directly into a vein.
  • Topical: You rub the drugs in a cream form onto your skin.
  • Oral: You swallow a pill or liquid that has the drugs.

 

Needle: Drugs may be sent through a thin needle in a vein on your hand or lower arm. Your nurse inserts the needle and removes it when treatment is done. Tell your doctor right away if you feel pain or burning during treatment.

Catheter: It’s a soft, thin tube. Your doctor puts one end into a large vein, often in your chest area. The other end stays outside your body and is used to deliver chemotherapy or other drugs, or to draw blood. It usually stays in place until all your treatment cycles are finished. Watch for signs of infection around your catheter.

Port: It’s a small disc that a surgeon places under your skin. It’s linked to a tube (catheter) that connects to a large vein, usually in your chest. A nurse may insert a needle into your port to give you chemotherapy drugs or draw blood. The needle can be left in place for treatments that last more than a day. Tell your doctor if you notice any signs of infection around your port.

Pump: Often attached to catheters or ports, it controls the amount of chemotherapy drugs, and how fast they get into your body. You may carry this pump with you, or a surgeon may place it under your skin.

There’s no way to know for sure. It depends on your overall health, the type of cancer you have, how far along it is, and the amount and type of chemotherapy drugs. Your genes may also play a part.

It’s common to feel ill or very tired after chemotherapy. You can prepare for this by getting someone to drive you back and forth from treatment. You should also plan to rest on the day of and the day after treatment. During this time, it may help to get some help with meals and child care, if necessary. Your doctor may be able to help you manage some of the more severe side effects of chemotherapy.

Usually, chemo is given in cycles, and depending on the treatment regimen, your oncologist can give you a general sense of the cycle of recovery.

It depends on the work that you do and on how you feel. On days you don’t feel well, you may want to see if you can work fewer hours or work from home. In some cases, employers are required by law to adjust your schedule when you have cancer treatment. A social worker may be able to help you learn about what the law allows.

It depends on the type of chemotherapy, how much you get, and how often you get it. It also depends on where you live, and whether you get treatment at home, in an office clinic, or during a hospital stay. Make sure to read your health insurance policy to find out exactly what it will and won’t pay for, and whether you can go to a doctor that you choose for your chemotherapy treatment.