What is radiation therapy?
Radiation therapy, also known as radiotherapy, is a common treatment for cancer where radiation is used to destroy or shrink a tumor. It is often combined with other therapies, such as chemotherapy, surgery, targeted therapy or hormone therapy.
During radiation therapy, high-energy radiation from X-rays, gamma rays, protons or electron beams is used to precisely target tumors. The radiation damages the DNA inside cancer cells, causing them to stop dividing and die. The goal of radiation therapy is to treat a specific part of the body to reduce damage to normal cells.
More than half of people in the United States diagnosed with cancer will have some form of radiation therapy.
Types of radiation therapy
External beam radiation therapy (EBRT)
During EBRT, a machine aims radiation at a specific part of your body to target the tumor. Most machines use photon beams, which can target tumors deep inside your body. Proton beams, which are made up of electrons (particles with a positive charge), can also be used.
A computer analyzes images of your body to calculate the precise dose and treatment path for the radiation, minimizing damage to nearby healthy cells. There are several different types of external beam radiation therapy:
- 3D conformal radiation therapy: MRI and CT images allow doctors to design radiation beams that conform to the size and shape of the tumor. Beams are delivered from many directions, allowing the machine to use high doses of radiation without harming nearby healthy tissue.
- Intensity-modulated radiation therapy (IMRT): IMRT is a type of 3D conformal radiation therapy that uses smaller beams of radiation. Their strength can be varied to give higher doses to parts of the tumor.
- Image-guided radiation therapy (IGRT): This is a type of IMRT where images are taken during treatment to detect changes in the tumor’s size and location. The radiation dose can be adjusted to improve accuracy.
- Stereotactic radiosurgery: This is often used to treat small tumors in your brain or spinal cord when surgery is not an option. Small beams aimed at the tumor from different directions deliver a precisely targeted dose of radiation to the tumor with less damage to nearby areas.
- Stereotactic body radiation therapy (SBRT): Similar to stereotactic radiosurgery, radiation beams are used to target small tumors outside the brain, such as those in the liver and lungs.
Internal radiation therapy
Internal radiation therapy, also called brachytherapy, is often used to treat cancers of the prostate, breast or cervix. It involves the placement of a radioactive implant on or near a tumor. The implant is sealed inside a pellet, seed or other implant directly in your body using a small tube called a catheter or another application device. The radiation from the implant precisely targets the tumor, killing the cancer cells. Internal radiation therapy allows doctors to deliver a higher dose of radiation than external beam radiation therapy.
The implants can be temporary or permanent. The type of implant you receive will depend on your cancer type, its location and your general health.
Radiopharmaceuticals
Radiopharmaceuticals are a new class of drugs that target cancer cells, delivering radiation therapy directly. The Food and Drug Administration has approved radiopharmaceuticals to treat advanced prostate cancer that has not responded to other therapies.
How to prepare for radiation therapy
Your care team, including your radiation oncologist (a cancer doctor who specializes in radiation therapy) and other healthcare professionals, will plan your treatment. Your doctor will explain what to expect from treatment, your treatment schedule and possible side effects. You will have a chance to ask questions and raise any concerns.
Your doctor will tell you if you need to do anything, such as stop taking other medicines or follow a special diet. You might also need to talk to your employer about taking time off and ask a family member or friend to drive you to appointments.
It is normal to feel anxious and overwhelmed following a cancer diagnosis. Your nurse navigator can connect you with cancer support services that may help you manage the emotional and physical aspects of your care.
What to expect
Your radiation treatment will take place at an outpatient center or hospital. Before your first appointment, you will have a planning appointment with your care team. You will have a physical exam and, in some cases, imaging tests.
On the day of the appointment, you should arrive on time and wear comfortable, loose-fitting clothes that are easy to take off if required. Follow any instructions from your doctor about what to eat. If you are having internal radiation therapy, you may need to prepare to stay overnight in the hospital.
Before treatment
Your doctor will examine you, review your medical history and test results, and identify the area to treat.
If you are having external beam radiation therapy, you will be asked to take part in a simulation. A radiation therapist will use imaging scans to identify the exact places on your body where the beams will be aimed. They might use a mold or mask to make sure you are in the same position for treatment and mark the treatment areas using semi-permanent ink. Your care team will calculate the exact dose of radiation required.
During treatment
External beam radiotherapy is similar to getting a regular X-ray. Your radiation therapist will set up the equipment and tell you how to position yourself. They may also use special shields to protect parts of your body that are not being treated. You will receive radiation treatment while your therapist operates the equipment from another room. You can talk to them over an intercom the entire time.
Your treatment will likely last only a few minutes, but the entire process may take up to 30 minutes.
Internal radiation therapy takes place in a hospital room designed to keep radiation in the room. You will have an anesthetic, so you will not feel anything. An imaging test, such as an X-ray or scan, might be used to ensure the implant is inserted in the right location.
After treatment
You usually receive external beam radiation therapy at an outpatient clinic, meaning you can go home after your appointment. You might feel very tired and need to rest. Your treatment schedule will typically involve appointments five days a week for a number of weeks, with weekends off for your body to recover.
You might have to stay in the hospital after brachytherapy, but in some cases, you can have it as an outpatient procedure, just like external radiation therapy. Due to the radioactive implant, you may need to limit time spent around other people, especially small children and pregnant women.
Radiation therapy side effects
Radiation can damage healthy cells as well as cancer cells, leading to side effects. These can depend on the type of cancer, treatment and radiation dose. Some people experience many side effects, while others are not affected.
Common side effects are fatigue and changes to your skin after treatment. You might also experience:
- Changes in taste
- Diarrhea
- Hair loss
- Headache
- Fertility problems
- Mouth problems
- Nausea and vomiting
- Sexual problems
- Skin changes
- Swelling
- Throat problems, such as difficulty swallowing
- Thyroid issues
- Urinary and bladder problems
Long-term side effects
Most side effects go away a few months after treatment, but some people have late side effects, which are side effects that develop months or years after treatment. Late side effects of radiation therapy include joint problems, mouth problems and infertility. Although rare, radiation therapy can increase your chances of getting another type of cancer later in life.
Talk to your doctor or nurse before or after treatment about side effects and how you can manage them. If you are concerned about your ability to have children in the future, your doctor can recommend fertility preservation options before treatment.
Frequently asked questions
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How long is radiation therapy?
The length of your treatment will depend on the type of radiation you receive, your cancer and how your body responds to treatment. Typically, external beam therapy is given five days a week for one to six weeks. With brachytherapy, you might receive outpatient treatment that allows you to go home the same day.
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Is radiation therapy painful?
External beam radiation therapy is similar to getting an X-ray and should not be painful. You will be given a local or general anesthetic during internal radiation therapy. You might feel some discomfort if it is being held in place by an applicator.
Let your radiation therapist know if you feel discomfort or pain. You might experience painful side effects after treatment, such as skin soreness, headaches, or breast or chest pain, depending on where you had treatment. Your doctor can help you manage these side effects.
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Does radiation therapy make you lose hair?
Radiation therapy only causes hair thinning or hair loss in the area being treated. If you have radiation to your head, you might lose your hair, including eyebrows and eyelashes. Your hair will usually grow back after treatment, but it might be thinner or have a different texture.
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Does radiation therapy make you sick?
Nausea and vomiting are common side effects of radiation therapy and can affect you a few hours after treatment. They are more likely if you get high doses of radiation or treatment to your abdomen, brain or liver. Combining radiation therapy with chemotherapy increases the chance you will feel sick.
Your doctor or nurse navigator can give you tips for managing nausea and vomiting and give you medicine if you need it. You may be able to reduce these side effects if you eat a bland snack just before or after treatment, or try relaxation techniques.
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Is it safe to be around someone receiving radiation therapy?
If you have external beam radiotherapy, you will not be radioactive, as there is no radiation in your body. However, brachytherapy will cause you to give off radiation for a while. You will probably stay in a private hospital room, and healthcare staff will wear protective clothing. You might not be able to have visits from young children and pregnant women, while other visitors should follow safety measures.
Your doctor or nurse will advise you on what precautions to take and for how long.
More information
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