What Happens to Your Body When You Have Chemotherapy

Chemotherapy is one of the most common and effective forms of cancer treatment. Despite doing its job of destroying cancer cells, chemotherapy drugs also impact healthy cells and cause a wide range of side effects. 

In this blog, Brian Geister, M.D., and Agnel Raparthi, M.D., both with the INTEGRIS Health Cancer Institute, weigh in on how chemotherapy affects the body.

Chemotherapy side effects

Chemotherapy drugs target growing cancer cells, but they can also damage or destroy growing healthy cells in your body.

Skin cells, hair cells, cells in bone marrow and cells in the mouth and digestive tract grow fast – think how rapidly hair regrows. As such, they’re the most likely to be impacted by chemotherapy.

That’s why skin changes, hair loss, gastrointestinal complications (nausea, diarrhea, constipation, stomach pain) and low blood counts are among the most common symptoms regardless of drug type.

The following is a list of the most common side effects:

Fatigue: Most often, patients receiving chemotherapy lack energy and deal with fatigue most days. In short, the body is working harder as it attempts to fight cancer and repair cells damaged by chemo. Chemo fatigue usually peaks a few days after treatment and may slightly subside between treatments.

Hair loss: Hair follicles damaged by chemo drugs cause thinning and hair loss. While hair loss is mostly associated with the hair on your head, your eyebrows, eyelashes, armpit hair and pubic hair are also affected. These changes usually start two to four weeks after your first chemotherapy treatment. The hair will begin to grow back two to three months following the conclusion of treatment.

Bruising and bleeding: Damage to bone marrow cells can lead to low platelets, which makes it harder for blood to clot and can lead to more bleeding and bruising than normal. 
Infection: Infection risk is much higher in cancer patients undergoing chemo because neutrophils (white blood cells that help fight infection) can be destroyed, although they will be replaced by new cells. Some chemo drugs cause neutropenia, a condition that creates a low count of neutrophils.

Anemia: Certain chemo drugs damage red blood cells, which limits your ability to deliver oxygen to tissues. Anemia can produce fatigue, shortness of breath and rapid heartbeat.

Changes in taste: Cells on taste buds can be damaged, which alters your tongue’s ability to distinguish flavors. For example, taste buds that usually detect sweetness may not work as well, thus making some foods taste bitter.

Nausea: Chemo drugs can either damage cells in the gastrointestinal tract or stimulate the chemoreceptor trigger zone in the brain, both of which cause nausea. IV chemo drugs may cause nausea to occur more rapidly since it’s absorbed quicker. Nausea is most common in the first week after chemo.

Constipation: Some drugs, such as a type of anti-mitotic called vinorelbine, impact the nerve supply in the GI tract and cause it to slow down to cause constipation. 

Diarrhea: Damage to cells in the lining of the intestines can alter water absorption, causing frequent diarrhea. This usually occurs within the first few days after chemo. Some people also can experience temporary lactose intolerance, affecting the body’s ability to digest lactose found in dairy products.

Mouth sores/difficulties swallowing: Mouth ulcers can develop when taking certain types of chemo drugs, making it harder to eat spicy, acidic or hard foods. You may also experience pain when swallowing five to 10 days after treatment. People undergoing chemo are also more susceptible to developing thrush, a yeast infection of the mouth that causes cottage cheese-like lesions.

Peripheral neuropathy: Some chemo drugs affect the nerves in your hands and feet, causing numbness, tingling and pain in these extremities. This complication is often permanent.

Cold sensitivity: Damage to nerves can also make you more sensitive to the cold, either cold temperatures or cold drinks. For example, some people experience pain or discomfort when eating ice cream or consuming a frozen drink.

Skin and nail changes: Skin damage can occur in as many as 90 percent of patients receiving chemo. These changes include hardening of nails, rashes, itching, dry skin, redness and swelling.

Urinary problems: Chemo drugs can irritate the bladder and kidneys, making it harder to urinate. You may also experience an increased urge to urinate.

Changes in libido and sexual function: Chemo drugs can cause a decrease in estrogen and an increase in vaginal dryness in women and a decrease in testosterone in men.

Fertility problems: Chemo drugs can affect the ovaries, causing changes to menstrual cycles that make it more difficult to become pregnant.

Muscle pain: Some people may experience pain, burning and numbness, especially in the hands and feet. This can be muscle, bone or joint pain.

Side effects by type of chemo

There are more than 100 types of chemo drugs broken down into a handful of groups. Side effects usually depend on the type administered. The list below is limited and does not include all the chemo drugs available.

Alkylating agents: These chemo drugs are the most common type used for a variety of cancers. They work by preventing cancer cells from dividing by cross-linking DNA strands. Alkylating agents are most effective against slow-growing cancers such as colorectal and prostate cancers.

Cyclophosphamide:

• Infection
• Anemia
• Bruising, bleeding
• Blood in urine
• Nausea, vomiting, diarrhea, abdominal pain, loss of appetite
• Mouth sores
• Infertility due to absence of menstrual period
• Hair loss
• Skin changes, rash, change in nails

Temozolomide:

• Headache, seizure
• Constipation, nausea, vomiting, diarrhea, abdominal pain, loss of appetite
• Trouble with memory
• Difficulty sleeping
• Muscle weakness, paralysis, difficulty walking
• Dizziness
• Fatigue
• Hair loss

Mitotic inhibitors: A type of plant alkaloids, mitotic inhibitors work by stopping cells from dividing during a process called mitosis. The drugs bind to tubulin, a protein used to create microtubules. Microtubules are structures that pull apart chromosomes during cell division.  

Cabazitaxel: 

• Infection
• Anemia
• Bruising, bleeding
• Vomiting, nausea, diarrhea or constipation
• Fatigue

Vinblastine:

• High blood pressure
• Infection
• Anemia
• Bruising, bleeding
• Pain in the bones or jaw
• Constipation
• Fatigue
• Hair loss

Vincristine: 

• Headache, jaw pain and/or bone/muscle pain
• Numbness and tingling of fingers or toes
• Swelling in lower legs
• Muscle weakness and difficulty walking
• Constipation, nausea, vomiting, diarrhea
• Hair loss

Antitumor antibiotics: Not to be confused with antibiotics to treat bacterial infections, these drugs interfere with cancer cells’ ability to create proteins, which they need to survive. Antitumor antibiotics can damage the heart in high doses, so people receiving this type of chemo are limited to a lifetime amount they can receive.

Doxorubicin:

• Nausea, vomiting
• Red colored urine, saliva or sweat
• Hair loss

Mitoxantrone:

• Infection
• Bruising, bleeding
• Anemia
• Nausea, vomiting
• Mouth sores
• Hair loss

Bleomycin:

• Mouth sores
• Vomiting, decreased appetite
• Fever, chills (usually within hours of treatment)
• Changes in skin color (darkening, stripes on skin, colored bumps on fingertips, palms, elbows and toes)
• Skin changes (redness, tenderness, itching)
• Hair loss

Antimetabolites: These drugs trick DNA by mimicking nutrients cancer cells need to reproduce. Eventually, the cancer cells starve and die off.

5-fluorouracil (5-FU):

• Diarrhea, nausea, vomiting
• Mouth sores
• Hand-foot syndrome
• Increased risk of sunburn
• Skin changes (itching, blisters on the skin, dry skin)

Gemcitabine:

• Swelling of arms, legs and body
• Shortness of breath
• Infection
• Bruising, bleeding
• Anemia
• Blood in urine
• Mouth sores
• Nausea, vomiting, diarrhea, constipation
• Flu-like symptoms of muscle pain, fever, headache, chills and fatigue
• Burning, numbness, tingling or "pins and needles" feelings
• Rash, itching
• Hair loss

Methotrexate:

• Brain swelling
• Cognitive changes
• Anemia
• Bruising, bleeding
• Infection
• Pain
• Vomiting
• Confusion, dizziness
• Difficulty speaking
• Fatigue
• Rash

Topoisomerase inhibitors: Another type of plant alkaloids, topoisomerase inhibitors work by interacting with enzymes called topoisomerases that help separate DNA. By inhibiting these enzymes, cancer cells can’t duplicate.

Irinotecan:

• Infection
• Bruising, bleeding
• Anemia
• Nausea, vomiting
• Mouth sores
• Hair loss

Etoposide:

• Infection
• Bruising, bleeding
• Anemia
• Nausea, vomiting
• Mouth sores
• Hair loss

Topotecan:

• Infection
• Bruising, bleeding
• Anemia
• Diarrhea, nausea, vomiting
• Tiredness
• Hair loss

How long does chemo stay in your body?

Chemotherapy stays in your body for two to three days (48 to 72 hours). Some drugs can take up a week for your body to break them down.

Once the kidneys and liver break down the chemo, your body excretes the remnants through urine, sweat, stool and vaginal fluid (in women).

Long-term side effects of chemotherapy

Although chemotherapy drugs don’t physically stay in your body for long, the side effects can have a lasting impact on the body.

Side effects can either develop months after treatment or can linger for months or years after treatment. In some cases, the changes can be permanent. 

While uncommon, some drugs can cause permanent damage to the heart, lungs, kidneys and the nervous system. Certain types of chemo can even cause a second cancer, such as leukemia, many years later.

Fatigue: The constant feeling of being tired can linger for three or four months after chemo treatments stop. Some people may even experience fatigue for a year.

Nerve damage: In most cases, damaged nerves will slowly grow back at a rate of around one millimeter per day. In other words, it can take months or a year for some types of nerve damage to improve. Other times, nerve damage can be permanent and will cause numbness or tingling in the hands or feet.

Early menopause: In some chemo drugs, such as those for breast cancer, women over the age of 40 experience early menopause in which regular menstrual cycles stop.

Weight gain: A combination of long-term metabolism changes and a sedentary lifestyle can lead to weight gain long after completing treatment.

Chemo brain: Some patients experience chronic mental fogginess, also known as chemo brain. These symptoms can be mild or more noticeable and impact daily tasks. Chemo often affects short-term memory.

Ask your doctor to explain the side effects for the particular chemotherapy regimen you’re on. A cancer diagnosis can lead to countless questions. Let INTEGRIS Health help with the answers. Learn more about cancer care at INTEGRIS Health here.