What is radiation therapy?

Radiation Therapy

Radiation therapy for cancer pain: Overview

Radiation can be used to control pain by destroying a growing tumor that is invading or interfering with normal tissue, such as when a tumor presses on bones, nerves, or other organs. This may be done with radiation to part of the body or, in rare cases, with radiation to the whole body. Or you may be given a shot with a radioactive medicine.

Radiation therapy is the use of X-rays to destroy cancer cells and shrink tumors. Radiation damages the cells in the area being treated, stopping or slowing the growth of the cancer cells.

Radiation therapy

Radiation therapy is the use of high-energy radiation, such as X-rays, to destroy cancer cells and shrink tumors. Radiation may come from a machine outside the body (external radiation therapy). Radiation can also be given from inside your body (internal radiation therapy). For example, brachytherapy uses radiation implants that are placed in or near the cancer. Systemic radiation therapy is given by a pill or injection. And intraoperative radiation therapy is given inside the body during an operation.

Radiation therapy is standard treatment for many types of cancer. It may be used in combination with other treatments, such as surgery, chemotherapy, or immunotherapy.

What are the types of radiation therapy?

Radiation therapy may be done in a number of different ways. No matter how it's done, the goal is to damage cancer cells and shrink tumors while protecting your healthy cells as much as possible.

The type of radiation you will be given will be based on several things, such as the type of cancer or tumor it is and where the cancer is in your body.

External beam radiation therapy (EBRT).

EBRT comes from a machine that aims the radiation beam at the cancer. It is usually given in small doses over several weeks. But radiation therapy may be given in just a few larger doses or even a single dose. Some types of EBRT include:

  • Conformal therapy. This type of radiation therapy uses CT scanning or an MRI to map and plan your treatment. This makes the radiation dose strongest where the cancer cells are and reduces the dose everywhere else. Sometimes your treatment team may use very precise types of conformal therapy. Examples are intensity-modulated radiation therapy (IMRT) and image-guided radiation therapy (IGRT).
  • Particle therapy. This type of radiation therapy uses beams of subatomic particles, such as electrons, protons, and neutrons. Electron treatments can be useful for treating cancers near the surface of the body, such as skin cancer. Proton treatments can be especially useful in treating certain cancers in children.
  • Stereotactic radiation therapy. This delivers a high dose of radiation to a very precise target. Because it is so precise, it can be given in a single treatment for some brain and spine cancers. This is called stereotactic radiosurgery (SRS). Another type is given in a few treatments and can treat some cancers in the brain, spine, and other parts of the body. This is called stereotactic body radiation therapy (SBRT).
  • Total body irradiation. This is usually used before blood stem cell transplants.
Internal radiation therapy.

Internal radiation therapy is given by putting the radiation source inside your body. It is done for some cancers because radiation can be put exactly where the cancer is. Types of internal radiation therapy include:

  • Brachytherapy. This type of radiation therapy is given by placing radiation implants either in or near your cancer. Some types of implants are left in place, and some are taken out later. The ones that stay in place will stop putting out radiation after a while. Some types will be put in daily and taken out for a few days in a row. Others will be taken out after a few days.
  • Intraoperative radiation therapy. This type of radiation therapy is given inside the body during an operation. It uses higher doses of radiation than external beam radiation. It lets your team focus the radiation just where it's needed most.
  • Systemic radiation therapy. This is given as a pill or injection. The radioactive material in the pill or injection travels to the cancer. Sometimes this is called targeted radiation therapy. Some cancers are treated by a doctor injecting radioactive matter directly into a tumor.

Your doctor will plan a very specific dose of radiation for the cancer cells or tumor. Your treatment plan will be based on this dose. A certain "fraction" of that total dose will be given in each treatment.

  • Sometimes the total dose is given all at once, like in stereotactic radiosurgery. This is sometimes called "single fraction" therapy.
  • Sometimes the total dose is split into smaller amounts and given in more than one treatment. If it's just a few treatments, this is called "hypofractionated" therapy.
  • If it's split into many very small doses and given over more time, it's sometimes called "conventionally fractionated" or "traditionally fractionated" radiation therapy.

Talk to your doctor if you have questions about your treatment plan.

How can you manage the side effects of radiation therapy?


  • Be safe with medicines. Take your medicines exactly as prescribed. Do not stop or change a medicine without talking to your doctor first.
  • Ask your doctor before taking any medicine, including natural health products and over-the-counter medicines.

Appetite problems and nausea

  • Try to eat a variety of healthy foods, like fruits, vegetables, whole grains, and lean protein. If you don't feel like eating, drink liquid meal replacements for extra calories and protein.
  • Try to eat your main meal early.
  • Ask your doctor if you can take an over-the-counter medicine, such as dimenhydrinate (Dramamine) or meclizine (Antivert), to help with nausea.
  • If you are vomiting or have diarrhea:
    • Drink plenty of fluids to prevent dehydration. Choose water and other clear liquids. If you have kidney, heart, or liver disease and have to limit fluids, talk with your doctor before you increase the amount of fluids you drink.
    • When you are able to eat, try clear soups, mild foods, and liquids until all symptoms are gone for 12 to 48 hours. Other good choices include dry toast, crackers, cooked cereal, and gelatin dessert, such as Jell-O.

Rest and activity

  • Try to get some physical activity every day, but don't get too tired.
  • Get plenty of rest, and sleep as often as you feel the need. You may feel tired for several weeks.
  • Ask for help with daily errands and tasks.
  • Keep doing the hobbies you enjoy as your energy allows.

Managing stress

  • Consider joining a support group. Sharing your feelings with your partner, a good friend, or other people with similar problems is a good way to reduce tension and stress.
  • Practice some relaxation techniques. Methods like deep breathing, muscle relaxation, and meditation are all ways to lower your stress level.
  • Express yourself through art. Try writing, crafts, dance, or art to relieve stress. Some dance, writing, or art groups may be available just for people who have cancer.
  • Be kind to your body and mind. Getting enough sleep, eating a healthy diet, and taking time to do things you enjoy can contribute to an overall feeling of balance in your life and help reduce stress.
  • Get help if you need it. Discuss your concerns with your doctor or counselor.

Mouth sores

  • If your mouth is sore and dry, sip cool water or suck on ice chips.
  • Eat soft, bland foods that are easy to swallow, such as applesauce, cottage cheese, soft-cooked eggs, and yogurt.
  • Avoid spicy and salty foods. And avoid coarse foods such as raw vegetables, dry crackers, and nuts.
  • If you had radiation to your mouth area, clean your mouth and teeth often, because you have a greater chance of getting cavities. Use an extra-soft toothbrush and a mild toothpaste.
  • Do not smoke. Smoking can make your symptoms worse. If you need help quitting, talk to your doctor.

Skin care

  • Use lukewarm water for showers or quick baths. Pat yourself dry with a soft towel, being careful not to rub off any ink marks that are used for your radiation.
  • Be gentle with your skin in the treatment area. Wash skin gently, using only lukewarm water.
  • Avoid putting heating pads or cold packs or anything that is hot or cold on this skin.
  • Avoid rubbing or scratching the treated area, even if it is itchy.
  • Wear soft, loose fabrics.
  • Ask your doctor which soap and lotion products you can use.
  • Always wear sunscreen on exposed skin. Make sure to use a broad-spectrum sunscreen that has a sun protection factor (SPF) of 30 or higher. Use it every day, even when it is cloudy.
  • Avoid exposing the treated area to the sun.

How well does radiation therapy for cancer work?

Radiation is one of the main treatments used to kill cancer cells. But it doesn't always cure cancer. Researchers continue to study safer and more effective ways to use radiation therapy to treat cancer.

What are the side effects of radiation therapy for cancer?

Radiation therapy may shrink a tumor, give you relief from cancer symptoms, or possibly cure cancer. But it has risks for serious side effects. Your doctor will recommend radiation therapy if the doctor thinks that the benefit you may have from this treatment is greater than the risks.

Risks of radiation therapy during and right after treatment include:

  • Fatigue.
  • Nausea with or without vomiting.
  • Skin changes, such as flaking, peeling, or shrinking. Your skin may turn red or get darker. These changes are called radiation dermatitis.
  • Problems that are specific to the area being treated. One example is hair loss with radiation to the head or neck. Another example is urinary problems if the lower belly is radiated.

Most of these problems will go away soon after the treatment ends. Some side effects, such as skin damage, may last longer. And sometimes the side effects are permanent, such as when the salivary glands are damaged.

And sometimes side effects may show up months or years after radiation therapy. These can include:

  • Skin changes (from external radiation treatments).
  • Damage to the bowels that causes diarrhea and bleeding or an obstruction.
  • Chronic bladder or rectal irritation.
  • Vaginal scarring (vaginal fibrosis).
  • Memory loss.
  • Infertility (not able to get pregnant or get someone else pregnant).
  • Harm to your lungs or heart.
  • In rare cases, a second cancer caused by exposure to radiation.

Why is radiation therapy for cancer done?

Radiation therapy is used to destroy cancer cells and to shrink tumors.

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The content above contains general health information provided by Healthwise, Incorporated, and reviewed by its medical experts. This content should not replace the advice of your healthcare provider. Not all treatments or services described are offered as services by us. For recommended treatments, please consult your healthcare provider.