Chemotherapy is a common treatment for most types of cancer. However, this treatment can have a number of side effects on the body. Typically, it affects various areas of the body in some way.

Chemotherapy involves giving a person medications to kill cancerous cells. However, chemotherapy can also kill or slow the growth of healthy cells in the body.

In this article, we look at some of the effects that chemotherapy can have on the body.

We look at the effects on various systems in the body, mental health, and rare side effects.

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The circulatory system includes the heart, blood vessels, and lymph nodes.

A 2018 article from the National Cancer Institute (NCI) states that cancer treatments, including chemotherapy, may cause damage to the heart and cardiovascular system. They can cause high blood pressure, abnormal heart rhythms, or heart failure.

A review from 2020 states that there has been an increase in the number of people who had cancer developing high blood pressure. This may be due to anticancer treatments, such as chemotherapy.

Chemotherapy can also damage a person’s immune system by reducing the number of white blood cells, which help fight infection.

A 2021 study of rats investigated the effects of different types of chemotherapy on the immune system for ovarian cancer. The researchers concluded that each chemotherapy type caused different effects, some of which had negative effects on the immune system.

Learn more about the immune system here.

Chemotherapy may also cause problems in the digestive system.

It can cause diarrhea as it alters how the body breaks down nutrients from food and how it absorbs them into the body. According to the NCI, more than half of people receiving chemotherapy develop diarrhea.

It may also damage healthy cells lining the intestines and mouth, which can cause eating difficulties.

Chemotherapy can lead to changes in the nervous system. Many of these changes may clear within 1 year of finishing treatment. However, some people experience the symptoms for life.

Symptoms of nervous system changes include:

  • tingling, weakness, or numbness in hands or feet
  • pain when walking
  • feeling colder than usual
  • weak, tired, or achy muscles
  • loss of balance
  • trembling or shaking
  • stomach pain or discomfort
  • hearing loss
  • fatigue
  • confusion and memory issues
  • dizziness
  • depression

Research also states that chemotherapy can cause muscle wasting. This may affect a person’s quality of life and can cause severe weight loss.

Read about the central nervous system here.

In males, chemotherapy may reduce testosterone levels and libido. However, the treatment does not usually affect the ability to get an erection.

It may also affect a person’s sexual desire due to side effects such as:

  • fatigue
  • nausea
  • pain
  • mouth soreness

2019 research into females who had breast cancer states that chemotherapy did not cause any sexual dysfunction.

In females, chemotherapy may affect the ovaries, stopping them from releasing eggs and estrogen. This ovary damage can cause infertility and periods to stop. This is sometimes only temporary. However, for some people, it may be permanent.

A common side effect of chemotherapy is a skin rash. This can appear on many parts of the body, including:

  • scalp
  • face
  • neck
  • chest
  • upper back

It can be painful. The rash may also burn, sting, or itch.

Other common side effects of chemotherapy include dry skin, nail discoloration, and hair loss.

A 2019 survey found that 99.9% of people with breast cancer who had chemotherapy experienced hair loss. However, regrowth of scalp hair occurred in 98% of these cases.

Although nail changes often occur for those experiencing chemotherapy, these may clear after treatment finishes.

According to research, some animal studies indicate that chemotherapy can result in skeletal muscle atrophy. This means that there is a decrease in muscle mass.

Bone fractures sometimes occur as a result of a loss of muscle mass and strength. Therefore, this may put a person at a higher risk of broken bones.

Read more about bones here.

In some cases, chemotherapy can induce kidney dysfunction or kidney disease. This occurs particularly in the later stages of cancer.

This may happen as the kidneys try to remove the chemotherapy medications from the body, causing damage.

Some types of chemotherapy may also affect the bladder. Chemotherapy can damage cells and irritate the bladder lining, potentially causing pain, blood in the urine, and difficulty urinating.

Changes to the color and smell of the urine are typical side effects of some types of chemotherapy.

The Centers for Disease Control and Prevention (CDC) state that there is a term known as “chemo brain.” This refers to thinking and memory difficulties that a person may experience during and after cancer treatment.

The CDC add that a person may also experience mental health challenges alongside this, such as:

According to research, depression and anxiety are common among females with breast cancer following chemotherapy treatment.

Learn more about mental health here.

Sometimes, a person may experience rare side effects of chemotherapy.

The American Cancer Society advises people to contact their healthcare professional immediately if they experience any of the following rare side effects:

  • a fever higher than the healthcare team advises is typical
  • bleeding
  • unexplained bruising
  • rash
  • signs of an allergic reaction, such as swelling in the mouth and throat, severe itching, or difficulty swallowing
  • intense chills
  • pain or soreness at the chemotherapy entry site
  • unusual pain, including extreme headaches
  • breathing difficulties, including shortness of breath
  • long lasting diarrhea or vomiting
  • blood in the urine or stool

Below, we answer some common questions about the effects of chemotherapy on the body.

What is the most life threatening side effect of chemotherapy?

According to a 2015 article that the CDC published, the most life threatening side effect of chemotherapy may be neutropenia. This is where there is a decrease in infection-fighting white blood cells.

A decreased number of white blood cells means a person may be more prone to developing infections and other illnesses.

What can you not do on chemotherapy?

A person should consider avoiding the following when undergoing chemotherapy:

  • overexerting themselves
  • interacting with others who have infections
  • smoking
  • drinking alcohol
  • eating raw, spicy, acidic, or hard foods
  • taking vitamins, supplements, and probiotics
  • exposing themselves to UV light

A person who is receiving chemotherapy can speak with their doctor about other foods or activities to avoid.

How long does chemotherapy stay in the body?

The body usually takes around 48–72 hours to break down and dispose of chemotherapy medications.

A person with cancer may receive chemotherapy as a treatment because it can help to kill the cancerous cells. However, it may also destroy healthy cells, resulting in side effects that may cause permanent damage.

Chemotherapy can affect different systems around the body. However, not all people will experience these symptoms.

If a person develops any serious, rare side effects, they should contact their healthcare professional immediately.