Radiation therapy is one of the most common treatments for kids who have cancer. Doctors might use it to shrink a tumor before surgery, or they could combine it with chemotherapy.

It may be the only treatment your child needs to tackle their disease.

How It Works

Radiation therapy uses high-energy waves or particles to kill tumor cells. It damages DNA in the cells, so they can’t grow and spread.

The treatment only targets the place your child has cancer, but some normal cells are harmed, too. These cells often fix themselves. In time, they’ll start working as they should.

Types of Radiation Therapy

There are two. One comes from a machine outside your child’s body -- called external radiation. The other is internal, during which the radiation source travels through your child’s bloodstream or is placed inside their body near the tumor.

Kids who have surgery may get a small dose of radiation right before they’re stitched up. This helps kill any cancer cells left after the surgeon takes out the tumor.

The type of radiation your child will get depends on the kind of cancer they have and where it is. Most kids get external radiation.

External Radiation Therapy

Before their first external radiation treatment, your child will have a planning session called a simulation. The radiation therapist will map out the place needing treatment and mark it on your child’s skin with ink. Don’t wash this off. It will show the therapist exactly where to aim the radiation.

Your child’s doctor decides how much radiation your child needs. Not all kids need the same amount.

It doesn’t hurt, and it lasts only a few minutes (though it can take a while to get your child in the right position). Your child shouldn’t move during the treatment. Younger kids might need medicine or a special body cast to help them lie still.

You can’t be in the room with your child, but you can talk to them through an intercom. If they’re scared or feel sick, the therapist can stop the treatment.

Most kids have this therapy at a hospital or outpatient treatment center 5 days a week for up to 10 weeks. It’s a lot for your child to go through. But getting smaller doses of radiation more often helps protect normal cells.

And having the weekend off gives your child a chance to recover.

Internal Radiation Therapy

One type of internal radiation therapy is called brachytherapy. It uses a radiation source inside a sealed container called an implant. This goes inside your child’s body near the tumor.  

Your child may or may not stay in the hospital for the treatment. With high-dose brachytherapy, the implant is left in place for only a few minutes, so your child can go home right after. Lower doses are left in the body for a day or two. Your child will stay in a special room in the hospital during treatment so the radiation doesn’t affect other people. But you and other family members can come for short visits.

Sometimes your child may get a radioactive medicine by mouth or in a vein (IV). The treatment kills cancer cells as it travels through your child’s body.

Side Effects

Your child may have some of these from radiation therapy, no matter which type they get. Many are physical, but they can be mental and emotional, too.

Some happen in the first few weeks of treatment (your doctor may call these early side effects).  For instance, your child will probably feel very tired. This may last even after treatment stops. Your child should rest and sleep as much as possible.

Kids who have external radiation may have changes in their skin where they were treated.  It may get red and swollen like a sunburn, and its texture might change. Prescription creams and ointments may ease some of these things. Wash the area gently with warm water and a mild cleanser, and lightly pat it dry.

Other side effects depend on the amount of radiation, where your child had it, and whether it was external or internal. Common side effects include:

  • Nausea and vomiting
  • Belly pain
  • Hair loss
  • Low blood counts

If your child’s white blood cell count is low, they may have greater odds of infection.

Late Side Effects

Side effects can show up later in life, too. Doctors are learning more about them.

They happen when radiation causes long-lasting damage to the body. This can lead to problems with your child’s growth, fertility, heart, learning, and memory. It can also raise the chances that your child will get a second cancer.

Be sure to talk to your child’s care team about late effects, what to watch for, and the screening tests your child needs throughout life.

WebMD Medical Reference

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