How Chemotherapy Works: An Introductory Guide

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Cancer develops due to the uncontrollable growth of harmful cells or a tumor in the body. Types of cancer can differ based on the region where they grow in a person’s body or the type of bodily systems that are affected by that growth. Many people who are diagnosed with cancer are advised to undergo chemotherapy to treat the disease.

Approximately 650,000 patients with cancer receive outpatient chemotherapy in the U.S. each year. This type of treatment can be very effective in eliminating or stopping the spread of cancer, but it does have some risks to consider as well. Learn the basics about chemotherapy, including how it works, what to expect when undergoing treatment and the potential side effects to consider.

What Is Chemotherapy?

Chemotherapy, often referred to simply as “chemo,” is the use of specific types of medication to treat cancer. There are more than 100 chemotherapy drugs available that can be used individually or in different combinations to treat various types of cancer. These medications are developed to specifically target cells that are rapidly dividing and multiplying; some medications alter the harmful cancer cells’ DNA, while others rely on blocking the chemical signaling that controls cell division. Depending on the specific mechanism of action, these drugs work by stopping or slowing the growth of cancer cells or by actually destroying the dividing cells.

Chemotherapy is different from radiation therapy and surgery in that chemotherapy affects a person’s entire body, while radiation and surgery affect only the area of the body where the cancer is located. In many cases, chemotherapy is combined with surgery or radiation therapy to treat cancer. Chemotherapy can also treat bone marrow diseases and immune system disorders.

Following a cancer diagnosis, chemotherapy can be used for several purposes:

  • Treating cancer: Sometimes chemo can destroy cancer cells to the point that cancer can no longer be detected in a patient’s body. In many cases, the cancer cells won’t grow back once the treatment has reached this point.
  • Controlling cancer: Chemo can also be utilized to stop or slow the spread of cancer to other parts of the body or kill cancer cells that have already spread.
  • Easing cancer symptoms: Chemo can shrink tumors that are causing pain or pressure. This is also known as palliative care.

What to Expect When Undergoing Chemotherapy

The specifics of your chemotherapy treatment will depend on the healthcare professional you’re working with, the type and severity of the cancer you have and the types of medications your health insurance covers, among other factors. You may receive your treatment at home, in a clinic, in a hospital or in a healthcare professional’s office. While some patients receive treatments daily, others only need them weekly or monthly. However, most professionals arrange for their patients to receive treatment in cycles to allow for periods when their bodies have time to rebuild healthy cells.

There are several ways doctors can administer chemotherapy drugs. Ask about these different options if you have concerns about how you’ll receive your treatments:

  • Oral: You may take the medications by mouth in pill, capsule or liquid form.
  • Topical: The drug is administered on your skin as a cream, gel or ointment.
  • Continuous infusions: This process involves the use of an electronic IV pump that administers the drugs over a period of one to seven days.
  • Injections: The drugs may be injected into certain areas (the spinal canal, a muscle, an artery, etc.) to treat a more specific area of your body.
  • Catheter: This involves inserting a catheter into your forearm or hand, and the chemotherapy drugs are injected into the catheter through a syringe. The catheter can be placed each time a treatment takes place. However, you might also have a central venous catheter temporarily placed in your chest or upper arm for easy access at each treatment. This process can take just a few minutes.
  • IV infusion: This is similar to a catheter except that the drugs are mixed into a solution and administered through tubing attached to the catheter. This takes between 30 minutes and a few hours to complete.

Potential Side Effects of Chemotherapy

Many of the side effects chemotherapy causes are a result of the drugs affecting your entire body (including healthy cells) in addition to the areas the cancer is affecting. Some vulnerable areas that are often affected by chemotherapy include the mouth, intestines, cells responsible for hair growth and bone marrow.

The following are some potential side effects of chemotherapy:

  • Loss of appetite
  • Nausea or vomiting
  • Easy bruising
  • Fatigue
  • Hair loss
  • Anemia
  • Fever
  • Mouth sores
  • Pain
  • Diarrhea or constipation

Your healthcare provider can help you find ways to manage or alleviate these side effects if you experience them. For instance, certain dietary changes can help with diarrhea, and many people choose to purchase wigs and scarves to cover their heads after experiencing hair loss.

Possible Health Risks of Chemotherapy

In addition to the side effects that may arise because of chemotherapy treatments, there are also a few possible long-term health risks that may appear during or after completion of your treatment. These risks include:

  • Weakened immunity and increased risk of infection
  • Infertility
  • Heart problems
  • Kidney problems
  • Nerve damage
  • Damage to lung tissue
  • Risk of getting another type of cancer

Chemotherapy does come with risks, but it has also saved thousands of lives. It’s important to consult with your healthcare provider about the pros and cons of chemo treatment, learn how the drugs will be administered and ask about ways to manage possible side effects.