Radiation side effects

Radiation side effects: Symptoms and management

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Radiation side effects: Symptoms and management

Though the radiation is targeted, it affects healthy cells as well as cancerous ones. For this reason, people undergoing radiation therapy (RT) can develop short- and long-term side effects during and after treatment.

This article describes common side effects of RT and provides tips for management and care.

Types of RT

There are two types of RT: external beam radiation and internal radiation.

External beam radiation

This involves a machine sending beams of radiation to specific parts of the body.

The beams are lower-energy, and they intersect at the targeted areas, so that these receive higher doses of radiation. For this reason, cancer specialists, called oncologists, refer to the treatment as “localized.”

Internal radiation

Internal radiation kills cancer cells from inside the body.

This involves an oncologist either implanting solid radioactive material at the site of the tumor or giving the person liquid drugs made up of a radioactive substance. These can be taken orally or injected.

A solid source of radiation acts as a localized treatment. Radioactive beads, for example, are a common treatment for prostate cancer.

A liquid radiation source acts as a systemic treatment because it travels throughout the body.

Radiation side effects

RT effectively destroys cancer cells, but it also damages healthy cells. This can cause adverse effects during and after treatment. In some cases, a person may develop new side effects several months after the treatment ends.

The specific adverse effects can depend on the type of RT and the part of the body receiving the treatment.

Early side effects

According to the American Cancer Society, fatigue and skin changes are the most common early side effects of RT.

Examples of these skin changes include:

  • dryness
  • color changes, such as redness in some people
  • blistering
  • peeling
  • pain or tenderness
  • hair loss

Other early side effects of RT can include:

  • swelling or tenderness at the treatment site
  • mouth sores
  • a sore throat
  • difficulty swallowing
  • headaches
  • vision changes
  • nausea and vomiting
  • bladder or bowel changes
  • sexual dysfunction

Late side effects

These side effects can appear 6 months or longer after finishing RT and can include:

  • dry mouth and mouth sores
  • joint problems
  • thyroid problems
  • lymphedema, which is swelling in the arms or legs
  • infertility
  • secondary cancers

How to alleviate side effects

Before RT begins, a doctor will describe the adverse effects that a person may experience during and after the treatment.

If any side effects arise during treatment, inform the doctor as soon as possible — some effects indicate that the treatment program should be changed or that the person should be taking radioprotective drugs.

Other side effects may improve with lifestyle changes and home care. Below, we look at ways of managing some side effects of RT.


The following care strategies can help alleviate fatigue:

  • sleeping for at least 8 hours each night
  • taking short naps during the day
  • limiting strenuous, physically demanding tasks
  • asking friends and family members for help with daily tasks, such as cleaning and grocery shopping
  • performing a little light exercise each day
  • setting aside time for relaxing activities, such as yoga, meditation, and reading

Hair loss

To prevent hair loss, a person can try:

  • using hair products that are mild, such as baby shampoo
  • avoiding hairsprays, dyes, and other hair products that contain harsh chemicals
  • patting the hair dry with a towel, as opposed to rubbing the hair
  • avoiding hairdryers, flat irons, and curling irons

Skin changes

The following strategies can help a person care for sensitive or damaged skin:

  • refraining from rubbing or scratching the area
  • keeping the skin clean and dry
  • using gentle moisturizers or creams that repair the skin barrier
  • wearing soft fabrics
  • avoiding tight, restrictive clothing
  • wearing sunscreen, even on cloudy days

Mouth and throat changes

To manage mouth and throat pain or sensitivity, try:

  • avoiding foods that are hard, crunchy, spicy, or acidic
  • eating soft foods
  • cooking with sauces to help soften food
  • taking smaller bites
  • avoiding extremely hot foods and beverages
  • avoiding caffeinated beverages
  • drinking through a straw

Bowel and bladder changes

The strategies below can help with managing bowel and bladder issues resulting from RT:

  • drinking plenty of clear liquids each day to prevent dehydration and constipation
  • eating foods rich in potassium and sodium to maintain the body’s electrolyte balance
  • eating smaller meals throughout the day to improve digestion
  • eating yogurt, bananas, and other high-fiber foods to prevent diarrhea
  • avoiding hard-to-digest foods and beverages, such as dairy products, alcohol, and fried foods

Possible long-term effects

RT damages DNA inside cells, which can lead to long-term side effects.

The specific effects may depend on the location and doses of RT. Some examples of long-term side effects include:


The thyroid is a small butterfly-shaped gland that sits in the front of the neck. It produces hormones that regulate numerous functions, including:

  • body temperature
  • heart rate
  • metabolism
  • bone growth
  • muscle function

RT to the head or neck can sometimes cause hypothyroidism — which refers to the thyroid not producing enough hormones.

Experts estimate that 19–45%Trusted Source of people develop hypothyroidism after undergoing RT for nose, throat, head, and neck cancers.

A 2018 studyTrusted Source investigated thyroid changes in 56 people with nasopharyngeal carcinoma. On average, the participants’ thyroid glands shrank by as much as 39.8%, and their thyroid hormone levels decreased by 21.5% within 30 months of finishing RT.

After 36 months, however, the participants’ thyroids stopped shrinking, and their hormone levels stabilized.

Cognitive changes

A person who receives RT to treat a brain tumor may experience long-term cognitive changes, such as:

  • reduced processing speed
  • changes in attention and concentration
  • changes in verbal learning
  • decreased working memory
  • changes in executive functioning, which includes the ability to:
    • plan
    • think flexibly
    • exert self-control

Musculoskeletal problems

RT can weaken bones, leading to osteoporosis and an increased risk of fractures.

Radiation can also cause muscle cells to deteriorate, resulting in:

  • muscle atrophy
  • muscle weakness
  • localized pain

Secondary cancers

RT alters DNA inside cells, which can increase a person’s risk of developing cancer.

According to the American Cancer Society, previous exposure to radiation is a significant risk factor for most types of leukemia.

It is difficult to predict whether a person will develop secondary cancer after receiving RT. However, the following factors could increase the risk:

  • Age: Younger people who undergo RT may have a higher risk of developing a secondary tumor several years after completing the treatment.
  • Dose: The risk of developing cancer increases with higher doses of radiation.
  • Area of exposure: Certain organs are more susceptible to developing secondary cancer from RT, including the skin and breasts

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