Radiation Therapy

Over half of people with cancer get radiation therapy. Radiation therapy may be the only treatment you need. Many people get radiation therapy with surgery or chemotherapy.¹

This article covers how radiation therapy is used to treat cancer. Talk to your doctor about the risks and benefits of radiation therapy.

What is radiation therapy?

Radiation therapy is also called radiotherapy. It uses high doses of radiation. The most common types use high-powered X-rays. At low doses, X-rays can help see inside your body. At high doses, X-rays can kill cancer cells.²

Doctors called “radiation oncologists” oversee radiation therapy. They have extra training in treating cancer with radiation therapy. They will design your treatment plan. Other specialists may be involved.³

How does radiation therapy treat cancer?

High doses of radiation damage cancer cell DNA. When cancer cells cannot fix their DNA, they stop dividing and die. Radiation therapy typically takes days or weeks to kill cancer cells. Cancer cells will then keep dying for weeks or months after treatment.²

Radiation therapy is used to treat many types of cancer. The goal of radiation therapy may be to:²

• Try to cure cancer
• Prevent cancer from returning
• Stop or slow cancer growth
• Make other treatments easier
• Ease the symptoms of cancer, such as pain

Types of radiation therapy

There are 2 main types of radiation therapy: external and internal. External means radiation comes from outside your body. Internal means radiation comes from inside your body. The right type of radiation therapy for you depends on many factors.²

External beam radiation therapy (EBRT)

This is the most common type of radiation therapy. A machine outside your body aims radiation at the cancer cells. EBRT is a local treatment. It treats cancer in a specific body part. It will not give radiation to your whole body.^1-3

There are many types of EBRT. They vary based on the type, intensity, and speed of radiation. Some types of EBRT are designed to be used during surgery.³

Internal radiation therapy

Internal radiation therapy uses a source of radiation inside your body. It is used to treat tumors in certain body parts.^1-3

Solid radioactive seeds may be placed near the tumor. This is called “brachytherapy.” It is a local treatment. The radioactive seed will give off radiation to kill nearby cancer cells.^1-3

Liquid radioactive material is also possible. Different forms can be swallowed or taken through a vein. This is a systemic treatment. The radioactive material travels in the blood throughout the body. It will seek out and kill cancer cells.^1-3

What are the possible side effects of radiation therapy?

Radiation therapy can damage nearby healthy cells. This can cause side effects. Specific side effects depend on the part of the body receiving the radiation therapy. Radiation near the brain can cause headaches and memory problems. Radiation near reproductive areas can cause fertility problems.^3,4

The most common side effects of radiation therapy include:^3,4

• Appetite loss
• Diarrhea
• Fatigue
• Hair loss
• Mouth sores
• Nausea and vomiting
• Skin changes
• Urinary and bladder problems

Many side effects go away within a few months after treatment. Others show up months or years after treatment. These are called late effects.⁴

There are limits to how much radiation is safe over your lifetime. If a body part has reached this limit, radiation therapy may not be possible in that area.²

These are not all the possible side effects of radiation therapy. Talk to your doctor about what to expect with radiation therapy for cancer. Call your doctor if you have any changes that concern you.

Other things to know about radiation therapy

Before radiation therapy, you may have planning appointments. Doctors may simulate the procedure. You may get into position and receive imaging tests. This helps your doctors customize the procedure for you. Your healthcare team will talk to you about preparing for the procedure.³

Radiation therapy may happen at a treatment center or in a hospital. During external radiation, a doctor will operate a machine that moves around you. You will not feel anything during treatment. During internal radiation, a doctor may implant the radioactive material through a tube. They may instead give it into a vein through an intravenous (IV) line.³

Many people receive radiation therapy over a few treatment sessions. This helps reduce side effects from getting the full dose all at once. Healthy cells can recover between sessions.³

After radiation therapy, your doctor will talk to you about recovery. You can usually resume daily activities after external radiation. Most people go home the same day. Some forms of internal radiation risk exposing others to radiation. You may need to stay in the hospital for 1 to 2 nights.³