How does chemotherapy work? Understanding a common cancer treatment

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Decades ago, for clinicians to control or cure cancer, it needed to be small enough to remove with surgery or destroy using radiation therapy. If the disease was large or had spread beyond its point of origin, there wasn't much providers could do. Then came chemotherapy. If you or a loved one has been diagnosed with cancer, learning how chemotherapy works can help you better understand the treatment options.

Chemotherapy allows clinicians to treat cancer throughout the body, even when cancer spreads far from where it started. Chemotherapy is less precise than other forms of cancer treatment, but its ability to destroy cancer cells anywhere in the body is its greatest advantage, as well as why it can cause a wide range of side effects.

How chemotherapy works against cancer cells

All cells go through a series of phases to make new cells. Cancer cells move through the cell-making process, known as the cell cycle, faster than their healthy counterparts.

Fast-growing cells are inviting targets for chemotherapy drugs, which attack them during different parts of the cell cycle, depending on the medication. Traveling through the bloodstream, chemotherapy affects cancer cells and healthy cells alike. Unlike normal cells, though, the diseased cells typically don't bounce back.

Here are a few other important facts about how chemotherapy works:

• Chemotherapy can set the stage for or follow other types of treatment. For some patients, chemotherapy is their main treatment. Other patients, however, may receive chemotherapy to reduce the size of the cancer, making cancer easier to treat with radiation or surgery. Chemotherapy can also perform cleanup duty after those treatments to destroy any remaining cancer cells.
• Many factors contribute to the decision to use chemotherapy. Oncologists use chemotherapy to treat many types of cancer, from breast cancer and bone cancer to colorectal cancer and skin cancer. Whether chemotherapy is right for you depends on a variety of factors, including the type of cancer, its stage, and your overall health.
  
• Oncologists (physicians who diagnose and treat cancer) have many chemotherapy medications to choose from. More than 100 cancer-fighting chemotherapy medications are available, according to the American Society of Clinical Oncology.
  
• Sometimes, together is better. For some patients, the most effective treatment involves a combination of chemotherapy and other medications, such as immunotherapy.
  
• You can receive chemotherapy in a variety of ways. These include by mouth, IV, or injection, among others.

What's your type? The different kinds of chemotherapy

Just as cancer specialists may combine chemotherapy with other forms of treatment, they may also use different types of chemotherapy together. Using medications that attack cancer cells during different parts of the cell cycle can be beneficial for some patients. Major types of chemotherapy include:

• Alkylating agents. These medications attack cancer cells' DNA to prevent them from doing what they do best: make more of themselves. Unfortunately, however, these medications can damage bone marrow cells, which make blood cells. Occasionally, this can cause leukemia or blood cancer.
  
• Antimetabolites. A cell can't make a copy of itself unless its DNA can duplicate. Antimetabolites stop a cell's DNA from duplicating, bringing cell reproduction to a halt.
  
• Anti-tumor antibiotics. These medications alter cancer cells' genetic material so they can't make new cells.

Other types of chemotherapy include topoisomerase inhibitors, which disrupt substances essential to cancer cells' DNA, and mitotic inhibitors, which interfere with cell division.

Common side effects of chemotherapy

Chemotherapy is hard on your body. As a result, you'll likely have the treatment in cycles, with a few days of receiving medication followed by several weeks of rest before the next round. Why are chemotherapy treatments so taxing? Put simply, it's because, as chemotherapy works, it isn't picky about which cells it goes after.

Chemotherapy side effects occur when the drugs damage healthy cells in addition to cancerous ones. Side effects depend on the medication you receive, and not all patients experience the same symptoms. Many patients develop fatigue. Exercising regularly, getting help for sleep problems, and eating a variety of nutritious foods can reduce feeling extremely tired after chemotherapy.

Chemotherapy can also lead to:

• Hair loss. Hair follicles are some of the most common healthy cells harmed by chemotherapy, according to the American Cancer Society. As a result, many patients experience chemotherapy-related hair loss. You can take a wide range of steps to cope, such as wearing a hairpiece or taking medication to reduce hair thinning.
• Mouth sores. Chemotherapy can also impact healthy cells in the mouth. You can reduce your risk of mouth sores by practicing good oral hygiene.
  
• Nausea and vomiting. Your care team may prescribe medications to help with nausea and vomiting after chemotherapy. You can help by avoiding foods that trigger nausea or vomiting and eating light snacks throughout the day so your stomach isn't empty, which can make you feel worse.
  
• Pain. Chemotherapy can cause headaches, muscle discomfort, or burning in your fingers or toes due to nerve damage. Your cancer team can help you manage pain based on where and how it affects you.

After chemotherapy works, side effects may show up late

Unlike cancer cells, healthy cells are better equipped to improve after sustaining damage from chemotherapy, and the body often recovers quickly. Many side effects don't last long, but that's not always the case.

Some side effects are long-term or don't occur until months or years after treatment ends. Known as late effects, these problems can have a major impact on your health later in life. Chemotherapy can cause several late effects, including heart failure, abnormal heart rhythm, lung damage, symptoms of menopause, osteoporosis, dental problems, and more.

If you receive chemotherapy, be sure you know what type, and watch for potential problems once you finish treatment. If any late effects occur, giving your providers detailed information about your cancer treatment can help them make the most informed decisions about your care.

Need the support of a team of experts who can help you plan your next steps after a cancer diagnosis? Make an appointment at Reid Cancer Center.