jueves, 29 de marzo de 2018

Radiation Therapy for Cancer - National Cancer Institute

Radiation Therapy for Cancer - National Cancer Institute

National Cancer Institute

Radiation Therapy to Treat Cancer

  • Resize font
  • Print
  • Email
  • Facebook
  • Twitter
  • Google+
  • Pinterest
Credit: National Cancer Institute
Radiation therapy (also called radiotherapy) is a cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. At low doses, radiation is used in x-rays to see inside your body, as with x-rays of your teeth or broken bones.

How Radiation Therapy Works against Cancer

At high doses, radiation therapy kills cancer cells or slows their growth by damaging their DNA. Cancer cells whose DNA is damaged beyond repair stop dividing or die. When the damaged cells die, they are broken down and removed by the body.
Radiation therapy does not kill cancer cells right away. It takes days or weeks of treatment before DNA is damaged enough for cancer cells to die. Then, cancer cells keep dying for weeks or months after radiation therapy ends.

Types of Radiation Therapy

There are two main types of radiation therapy, external beam and internal.

External Beam Radiation Therapy

External beam radiation therapy comes from a machine that aims radiation at your cancer. The machine is large and may be noisy. It does not touch you, but can move around you, sending radiation to a part of your body from many directions.
External beam radiation therapy is a local treatment, which means it treats a specific part of your body. For example, if you have cancer in your lung, you will have radiation only to your chest, not to your whole body.

Internal Radiation Therapy

Internal radiation therapy is a treatment in which a source of radiation is put inside your body. The radiation source can be solid or liquid.
Internal radiation therapy with a solid source is called brachytherapy. In this type of treatment, seeds, ribbons, or capsules that contain a radiation source are placed in your body in or near the tumor. Like external beam radiation therapy, brachytherapy is a local treatment and treats only a specific part of your body.
Internal radiation therapy with a liquid source is called systemic therapySystemic means that the treatment travels in the blood to tissues throughout your body, seeking out and killing cancer cells. You receive systemic radiation therapy by swallowing or through a vein, via an IV line.
The type of radiation therapy that you may have depends on many factors, including:
  • The type of cancer
  • The size of the tumor
  • The tumor’s location in the body
  • How close the tumor is to normal tissues that are sensitive to radiation
  • Your general health and medical history
  • Whether you will have other types of cancer treatment
  • Other factors, such as your age and other medical conditions

Why People with Cancer Receive Radiation Therapy

Radiation therapy is used to treat cancer and ease cancer symtoms.
When treatments are used to ease symptoms, they are known as palliativetreatments. External beam radiation may shrink tumors to treat pain and other problems caused by the tumor, such as trouble breathing or loss of bowel and bladder control. Pain from cancer that has spread to the bone can be treated with systemic radiation therapy drugs called radiopharmaceuticals.
When used to treat cancer, radiation therapy can cure cancer, prevent it from returning, or stop or slow its growth.

Types of Cancer that Are Treated with Radiation Therapy

External beam radiation therapy is used to treat many types of cancer.
Brachytherapy is often used to treat cancers of the head and neck, breast, cervix, prostate, and eye.
Systemic radiation therapy is most often used to treat certain types of thyroid cancer. This treatment uses radioactive iodine, which is also known as I-131.

How Radiation Is Used with Other Cancer Treatments

For some people, radiation may be the only treatment you need. But, most often, you will have radiation therapy with other cancer treatments, such as surgerychemotherapy, and immunotherapy. Radiation therapy may be given before, during, or after these other treatments to improve the chances that treatment will work. The timing of when radiation therapy is given depends on the type of cancer being treated and whether the goal of radiation therapy is to treat the cancer or ease symptoms.
When radiation is combined with surgery, it can be given:
  • Before surgery, to shrink the size of the cancer so it can be removed by surgery and be less likely to return.
  • During surgery, so that it goes straight to the cancer without passing through the skin. Radiation therapy used this way is called intraoperative radiation. With this technique, doctors can more easily protect nearby normal tissues from radiation.
  • After surgery to kill any cancer cells that remain.

Lifetime Dose Limits

There is a limit to the amount of radiation an area of your body can safely receive over the course of your lifetime. Depending on how much radiation an area has already been treated with, you may not be able to have radiation therapy to that area a second time. But, if one area of the body has already received the safe lifetime dose of radiation, another area might still be treated if the distance between the two areas is large enough.

Radiation Therapy Can Cause Side Effects

Radiation not only kills or slows the growth of cancer cells, it can also affect nearby healthy cells. Damage to healthy cells can cause side effects.
Many people who get radiation therapy have fatigue. Fatigue is feeling exhausted and worn out. It can happen all at once or come on slowly. People feel fatigue in different ways and you may feel more or less fatigue than someone else who is getting the same amount of radiation therapy to the same part of the body.
Other radiation therapy side effects you may have depend on the part of the body that is treated. To see which side effects you might expect, find the part of your body being treated in the following chart. Many of the side effects in the list link to more information in the Side Effects section. Discuss this chart with your doctor or nurse. Ask them about your chances of getting each side effect.
Treatment Areas and Possible Side Effects
Healthy cells that are damaged during radiation treatment usually recover within a few months after treatment is over. But sometimes people may have side effects that do not improve. Other side effects may show up months or years after radiation therapy is over. These are called late effects. Whether you might have late effects, and what they might be, depends on the part of your body that was treated, other cancer treatments you've had, genetics, and other factors, such as smoking.
Ask your doctor or nurse which late effects you should watch for. See the section on Late Effects  to learn more.

How Much Radiation Therapy Cost

Radiation therapy can be expensive. It uses complex machines and involves the services of many health care providers. The exact cost of your radiation therapy depends on the cost of health care where you live, what type of radiation therapy you get, and how many treatments you need.
Talk with your health insurance company about what services it will pay for. Most insurance plans pay for radiation therapy. To learn more, talk with the business office at the clinic or hospital where you go for treatment. If you need financial assistance, there are organizations that may be able to help. To find such organizations, go to the National Cancer Institute database, Organizations that Offer Support Services and search for "financial assistance." Or call toll-free 1-800-4-CANCER (1-800-422-6237) to ask for information on organizations that may help.

What to Expect When Having External Beam Radiation Therapy

How Often You Will Have External Beam Radiation Therapy

Most people have external beam radiation therapy once a day, five days a week, Monday through Friday. Radiation is given in a series of treatments to allow healthy cells to recover and to make radiation more effective. How many weeks you have treatment depends on the type of cancer you have, the goal of your treatment, the radiation dose, and the radiation schedule.
The span of time from your first radiation treatment to the last is called a course of treatment.
Researchers are looking at different ways to adjust the radiation dose or schedule in order to reach the total dose of radiation more quickly or to limit damage to healthy cells. Different ways of delivering the total radiation dose include:
  • Accelerated fractionation, which is treatment given in larger daily or weekly doses to reduce the number of weeks of treatment. 
  • Hyperfractionation, which is a smaller dose than the usual daily dose of radiation given more than once a day.
  • Hypofractionation, which is larger doses given once a day or less often to reduce the number of treatments.
Researchers hope these different schedules for delivering radiation may be more effective and cause fewer side effects than the usual way of doing it or be as effective but more convenient.

Where You Go for External Beam Radiation Therapy

Most of the time, you will get external beam radiation therapy as an outpatient. This means that you will have treatment at a clinic or radiation therapy center and will not stay the night in the hospital.

What Happens before Your First External Beam Radiation Therapy Treatment

You will have a 1- to 2-hour meeting with your doctor or nurse before you begin radiation therapy. At this time, you will have a physical exam, talk about your medical history, and maybe have imaging tests. Your doctor or nurse will discuss external beam radiation therapy, its benefits and side effects, and ways you can care for yourself during and after treatment. You can then choose whether to have external beam radiation therapy.
If you decide to have external beam radiation therapy, you will be scheduled for a treatment planning session called a simulation. At this time:
  • A radiation oncologist (a doctor who specializes in using radiation to treat cancer) and radiation therapist will figure out your treatment area. You may also hear the treatment area referred to as the treatment port or treatment field. These terms refer to the places in your body that will get radiation. You will be asked to lie very still while x-rays or scans are taken.
  • The radiation therapist will tattoo or draw small dots of colored ink on your skin to mark the treatment area. These dots will be needed throughout your course of radiation therapy. The radiation therapist will use them to make sure you are in exactly the same position for every treatment. The dots are about the size of a freckle. If the dots are tattooed, they will remain on your skin for the rest of your life. Ink markings will fade over time. Be careful not to remove them and tell the radiation therapist if they have faded or lost color.
  • A body mold may be made of the part of the body that is being treated. This is a plastic or plaster form that keeps you from moving during treatment. It also helps make sure that you are in exactly the same position for each treatment
  • If you are getting radiation to the head and neck area you may be fitted for a mask. The mask has many air holes. It attaches to the table where you will lie for your treatments. The mask helps keep your head from moving so that you are in exactly the same position for each treatment.

What to Wear for Your Treatments

Wear clothes that are comfortable and made of soft fabric, such as fleece or cotton. Choose clothes that are easy to take off, since you may need to expose the treatment area or change into a hospital gown. Do not wear clothes that are tight, such as close-fitting collars or waistbands, near your treatment area. Also, do not wear jewelry, adhesive bandages, or powder in the treatment area.

What Happens during a Treatment Session

  • You may be asked to change into a hospital gown or robe.
  • You will go to the treatment room where you will receive radiation. The temperature in this room will be very cool.
  • Depending on where your cancer is, you will either lie down on a treatment table or sit in a special chair. The radiation therapist will use the dots on your skin and body mold or face mask, if you have one, to help you get into the right position.
  • You may see colored lights pointed at your skin marks. These lights are harmless and help the therapist position you for treatment.
  • You will need to stay very still so the radiation goes to the exact same place each time. You will get radiation for 1 to 5 minutes. During this time, you can breathe normally.
The radiation therapist will leave the room just before your treatment begins. He or she will go to a nearby room to control the radiation machine. The therapist watches you on a TV screen or through a window and talks with you through a speaker in the treatment room. Make sure to tell the therapist if you feel sick or are uncomfortable. He or she can stop the radiation machine at any time. You will hear the radiation machine and see it moving around, but you won’t be able to feel, hear, see, or smell the radiation.
Most visits last from 30 minutes to an hour, with most of that time spent helping you get into the correct position.

How to Relax for Treatment Sessions

Keep yourself busy while you wait:
  • Read a book or magazine.
  • Work on crossword puzzles or needlework.
  • Use headphones to listen to music or recorded books.
  • Meditate, breathe deeply, pray, use imagery, or find other ways to relax.
See Learning to Relax for exercises and other ideas on how to relax.

External Beam Radiation Therapy Will Not Make You Radioactive

People often wonder if they will be radioactive when they are having treatment with radiation. External beam radiation therapy will not make you radioactive. You may safely be around other people, even pregnant women, babies, and young children.
 What To Know About External Beam Radiation Therapy
(Type: MP3 | Time: 1:58 | Size: 1.9MB)

What to Expect When Having Internal Radiation Therapy

What Happens before Your First Internal Radiation Therapy Treatment

You will have a 1- to 2-hour meeting with your doctor or nurse to plan your treatment before you begin internal radiation therapy. At this time, you will have a physical exam, talk about your medical history, and maybe have imaging tests. Your doctor will discuss the type of internal radiation therapy that is best for you, its benefits and side effects, and ways you can care for yourself during and after treatment. You can then decide whether to have internal radiation therapy.

How Brachytherapy Is Put in Place

Most brachytherapy is put in place through a catheter, which is a small, stretchy tube. Sometimes, brachytherapy is put in place through a larger device called an applicator. The way the brachytherapy is put in place depends on your type of cancer. Your doctor will place the catheter or applicator into your body before you begin treatment.
Techniques for placing brachytherapy include:
  • Interstital brachytherapy, in which the radiation source is placed within the tumor. This technique is used for prostate cancer, for instance.
  • Intracavity brachytherapy, in which the radiation source is placed within a body cavityor a cavity created by surgery. For example, radiation can be placed in the vagina to treat cervical or endometrial cancer.
  • Episcleral brachytherapy, in which the radiation source is attached to the eye. This technique is used to treat melanoma of the eye.
Once the catheter or applicator is in place, the radiation source is placed inside it. The radiation source may be kept in place for a few minutes, for many days, or for the rest of your life. How long it remains in place depends on the type of radiation source, your type of cancer, where the cancer is in your body, your health, and other cancer treatments you have had.

Types of Brachytherapy

There are three types of brachytherapy:
  • Low-dose rate (LDR) implants
    In this type of brachytherapy, the radiation source stays in place for 1 to 7 days. You are likely to be in the hospital during this time. Once your treatment is finished, your doctor will remove the radiation source and the catheter or applicator.
  • High-dose rate (HDR) implants
    In this type of brachytherapy, the radiation source is left in place for just 10 to 20 minutes at a time and then taken out. You may have treatment twice a day for 2 to 5 days or once a week for 2 to 5 weeks. The schedule depends on your type of cancer. During the course of treatment, your catheter or applicator may stay in place, or it may be put in place before each treatment. You may be in the hospital during this time, or you may make daily trips to the hospital to have the radiation source put in place. As with LDR implants, your doctor will remove the catheter or applicator once you have finished treatment.
  • Permanent implants
    After the radiation source is put in place, the catheter is removed. The implants remain in your body for the rest of your life, but the radiation gets weaker each day. As time goes on, almost all the radiation will go away. When the radiation is first put in place, you may need to limit your time around other people and take other safety measures. Be extra careful not to spend time with children or pregnant women.

Internal Radiation Therapy Makes You Give Off Radiation

With systemic radiation, your body fluids (urine, sweat, and saliva) will give off radiation for a while. With brachytherapy, your body fluids will not give off radiation, but the radiation source in your body will. If the radiation you receive is a very high dose, you may need to follow some safety measures. These measures may include:
  • Staying in a private hospital room to protect others from radiation coming from your body
  • Being treated quickly by nurses and other hospital staff. They will provide all the care you need, but may stand at a distance, talk with you from the doorway of your room, and wear protective clothing.
Your visitors will also need to follow safety measures, which may include:
  • Not being allowed to visit when the radiation is first put in
  • Needing to check with the hospital staff before they go to your room
  • Standing by the doorway rather than going into your hospital room
  • Keeping visits short (30 minutes or less each day). The length of visits depends on the type of radiation being used and the part of your body being treated.
  • Not having visits from pregnant women and children younger than a year old
You may also need to follow safety measures once you leave the hospital, such as not spending much time with other people. Your doctor or nurse will talk with you about any safety measures you should follow when you go home.

What to Expect When the Catheter Is Removed

Once you finish treatment with LDR or HDR implants, the catheter will be removed. Here are some things to expect:
  • You will get medicine for pain before the catheter or applicator is removed.
  • The area where the catheter or applicator was might be tender for a few months.
  • There is no radiation in your body after the catheter or applicator is removed. It is safe for people to be near you—even young children and pregnant women.
For a week or two, you may need to limit activities that take a lot of effort. Ask your doctor what kinds of activities are safe for you and which ones you should avoid.
 What To Know About Brachytherapy (A Type of Internal Radiation Therapy)
(Type: MP3 | Time: 3:17 | Size: 3.1MB)

Special Diet Needs

Radiation can cause side effects that make it hard to eat, such as nausea, mouth sores, and throat problems called esophagitis. Since your body uses a lot of energy to heal during radiation therapy, it is important that you eat enough calories and protein to maintain your weight during treatment.
If you are having trouble eating and maintaining your weight, talk to your doctor or nurse. You might also find it helpful to speak with a dietitian. For more information about coping with eating problems see the booklet Eating Hints or the section on side effects.

Working during Radiation Therapy

Some people are able to work full-time during radiation therapy. Others can work only part-time or not at all. How much you are able to work depends on how you feel. Ask your doctor or nurse what you may expect from the treatment you will have.
You are likely to feel well enough to work when you first start your radiation treatments. As time goes on, do not be surprised if you are more tired, have less energy, or feel weak. Once you have finished treatment, it may take just a few weeks for you to feel better—or it could take months.
You may get to a point during your radiation therapy when you feel too sick to work. Talk with your employer to find out if you can go on medical leave. Check that your health insurance will pay for treatment while you are on medical leave.

No hay comentarios:

Publicar un comentario