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Cancer Health Library : Oncology
Cancer Treatment - Radiation Therapy For Cancer Treatment
Radiation therapy (also called therapeutic radiology or radiation oncology) uses special kinds of energy waves or particles to fight cancer. Like surgery, radiation therapy is used in several ways depending on the type and location of the cancer. Certain levels of radiation work to destroy cancer cells or prevent cells from growing or reproducing. This treatment may provide a cure for cancer, control the disease, or help relieve its symptoms. Most radiation treatments do not make you radioactive. Talk to your doctor about any precautions you should take when getting radiation therapy.
Although each hospital may have specific protocols, radiation therapy usually begins with these procedures:
- simulation process
After a physical examination and a review of your medical history, your treatment team "maps" out the position you will be in for each treatment and the exact location on your body (referred to as treatment field or port) where the radiation will be given. Sometimes, the area on your body that requires treatment will be marked to make sure radiation is given properly. The treatment team may also make molds, headrests, or other devices that help to position you during your treatment. Imaging studies may also be performed during the simulation process to help plan how to direct the radiation during your treatments.
- treatment plan
Once the simulation process is completed, the radiation oncologist will determine your treatment plan, including the type of machine to use, the amount (dose) of radiation that is needed, and the number of treatments that will be given.
Radiation therapy is given through different methods, depending on the type of cancer, the location of the cancer, and the patient's health. Sometimes, radiation therapy is used in combination with other treatments. The following are some of the different types of radiation therapy with brief explanations of their goals:
- external radiation (external beam therapy)
With external radiation, radiation is administered by a large machine that points the energy waves directly at the tumor. The radiation therapist controls the machine. Since radiation is used to kill cancer cells, special shields may be made to protect the tissue surrounding the treatment area. Radiation treatments are painless and usually last a few minutes.
- internal radiation (brachytherapy, implant radiation, systemic radiation)
With internal radiation, a high dose of radiation is given inside the body as close to the cancer as possible. The radiation treatment may be swallowed, injected, or implanted directly into the tumor. Some of the radioactive implants are called “seeds” or “capsules”. Internal radiation involves administering a higher dose of radiation in a shorter time span when compared with external radiation. Some internal radiation treatments stay in the body temporarily; other internal treatments stay in the body permanently, although the radioactive substance loses its radiation energy over time. In some cases, both internal and external radiation therapies are used.
Radiation therapy is a painless cancer treatment, though it can irritate skin. The biggest risk of radiation therapy involves potential damage to normal cells, in addition to the cancerous cells. This damage to the normal cells can cause some side effects, which will be monitored and treated by your cancer treatment team.
As each person's individual medical profile and diagnosis is different, so is his/her reaction to treatment. Side effects may be severe, mild, or absent. Be sure to discuss with your cancer care team any/all possible side effects of treatment before the treatment begins. Consider the following potential side effects of radiation therapy:
- skin irritation
Sometimes, radiation irritates the skin, causing it to become red, sore, and/or dry. For some people, skin irritation can become a troubling side effect. If you experience irritated skin during radiation treatment, consult your physician regarding how to treat the problem. Also, consider the following ways to protect your skin during treatment:
- Avoid exposure to sunlight during treatment.
- Avoid exposure to extreme cold or hot temperatures, such as from an ice bag or a heating pad.
- Be gentle with the skin at all times, and use mild soaps, lotions, and other products with caution. Ask your cancer treatment team for a list of recommended products and those to avoid.
- Use lukewarm water to wash the affected areas of your skin. Do not scrub the skin. Always pat the skin dry.
- Wear loose fitting clothing over the affected areas of skin.
Fatigue can be a common side effect for many cancer patients. After weeks of radiation therapy, most people experience fatigue. Fatigue often resolves after treatment is completed.
Scientists have not determined the exact cause of fatigue. It may result from many factors, such as stress, pain, or a loss of sleep. Experts suggest that cancer patients with fatigue save their energy by limiting their activities. Ask friends and family to help you with certain tasks, such as grocery shopping. Try to rest as much as possible. Also, including some light exercises, such as walking, into your daily routine may help you build energy.
- hair loss (alopecia)
Hair loss can occur around the area being treated with radiation. For example, if you have radiation to your head you may lose hair on your scalp. However, if you are receiving radiation to your lung, you will not lose hair on your head. Hair usually grows back after treatment is finished.
If you experience hair loss on your scalp following treatment for a head or neck cancer, you may consider wearing a wig. Other people choose to wear a hat or scarf. Or you may decide that none of these options are right for you. If you choose to wear something on your head, make sure it is comfortable and does not irritate your skin.
- blood changes
White blood cells and platelets can be affected by radiation therapy. Oncologists monitor blood counts during treatment to detect any problems. In some cases, the red blood cells can also be affected if radiation therapy is directed to large areas of bone marrow. It depends on your blood count, but your physician may choose to adjust your treatment if your white blood cell and platelet counts decrease. Since these blood cells fight infections and prevent bleeding, treatment may even stop for a while until the blood counts increase.
- oral health
Radiation treatment to the head and neck can cause dry mouth, difficulty in swallowing, cavities, gum destruction, sores in the mouth, redness and irritation, altered taste and smell sensations, and other side effects. It is important to take good care of your mouth, teeth, and throat during radiation therapy. Seeing a dentist before you start your radiation treatments can help prevent problems.
If you experience oral health problems during radiation treatment to the head or neck, talk to your physician and dentist about what you can do. Consider the following as ways to reduce your risk of side effects:
- Keeping your mouth moist. Drink water and use saliva substitutes if you have dry mouth.
- Clean your mouth regularly. Brush and floss your teeth after every meal and when you go to sleep. Make sure your toothpaste contains fluoride.
- Be careful about what you eat, as your diet affects the severity of side effects. Eat soft foods as much as you can and avoid spicy, crunchy, or sugary foods.
- Avoid mouthwashes that contain alcohol. Alcohol can cause the tissues of the mouth to become dry.
- diarrhea, nausea, and vomiting
Radiation therapy to the abdomen or stomach may cause these side effects. Some patients experience nausea and an upset stomach a few hours after radiation treatment to the abdomen or stomach. Some patients find it helpful to eat a light meal a few hours prior to their treatment, while others prefer not to eat before their radiation treatment. You will need to work out a dietary plan that works best for you. Diarrhea may also occur after a few weeks of radiation therapy to the abdomen or pelvis. Nausea, vomiting, and diarrhea are usually temporary side effects. You will likely not experience these side effects once your radiation treatments to the stomach and abdomen have been completed.
It is very important to maintain proper nutrition before, during, and after your radiation treatments. The main goal is to prevent weight loss.
If you have nausea and vomiting, choose foods that are easy to chew, swallow, and digest, such as the following:
- toast, crackers, and pretzels
- angel food cake
- cream of wheat, rice, oatmeal, and grits
- boiled potatoes, rice, and noodles
- skinned chicken that is baked or broiled, not fried
- canned peaches or other soft, bland fruits and vegetables
- clear liquids, such as bouillon, clear carbonated beverages, apple/cranberry/grape juice, plain gelatin, Popsicles`#174;, tea, and water
- ice chips
- carbonated drinks
With nausea and vomiting, try to avoid the following types of foods:
- fatty, greasy, or fried foods
- very sweet foods, such as candy or cookies, or cake with icing
- spicy hot foods
- foods with a strong odor
With nausea and vomiting, consider the following:
- Eat small amounts, often and slowly.
- Eat more of the foods that appeal to you.
- Eat in a place that is comfortable, avoiding stuffy places that are too warm or have cooking odors.
- Drink liquids a half hour before or after meals but not with your meals.
- Drink slowly or sip liquids throughout the day. Use a straw if necessary.
- Eat your food at room temperature or cooler, rather than hot.
- Do not force yourself to eat foods you normally like to eat because it may cause you to dislike them later when you feel better.
- Rest after you eat.
- For morning nausea, try eating crackers or toast before you get up.
- Wear loose fitting clothes.
- If you feel nauseated during treatment wait a couple of hours before eating.
- Keep a diary of when you feel nausea, how long it lasted, what you ate, and where you were. Your physician or nurse may need the information to help you better manage this side effect.
If you have diarrhea, consider foods such as the following:
- yogurt and cottage cheese
- rice, noodles, and potatoes
- farina and cream of wheat
- eggs (cooked until the whites are solid, not fried)
- smooth peanut butter
- white bread
- canned, peeled fruits, and well-cooked vegetables
- skinned chicken or turkey, lean beef, and fish (broiled or baked, not fried)
With diarrhea, try to avoid the following types of foods:
- fatty and fried foods
- raw vegetables
- fruit seeds, skins, and stringy fibers
- vegetables high in fiber such as broccoli, corn, dried beans, cabbage, peas, and cauliflower
Some people need to avoid milk and dairy products when they have diarrhea. This is because they may not tolerate the lactose contained in these products.
- difficulty in eating
Eating may be difficult during treatment. Radiation treatment can interfere with your body's ability to absorb and digest food. It is also normal to lose weight during radiation therapy, but eating a balanced diet is important.
Talk to your physician or a dietitian regarding what you should eat if you experience problems such as a loss of appetite. Patients who eat well usually cope better with treatment, both mentally and physically.
The following suggestions from the National Cancer Institute (NCI) can help if you have difficulty eating or loss of appetite even when you are feeling well with cancer:
- Eat small, frequent meals (every 1 to 2 hours).
- Eat high protein and high calorie foods (including snacks).
- Avoid foods low in calories and protein and avoid empty calories (such as soda).
- To avoid nausea and improve your appetite, do not drink liquids with your meals.
- Try to eat when you are feeling the best, no matter what time of day.
- Use meal substitutes, such as high-calorie, high-protein drinks, when you do not feel like eating.
- Try to increase your appetite through light exercise or appetite stimulants including a glass of wine or beer, if advised.
- Add extra calories and protein to food such as butter, skim milk powder, honey, or brown sugar.
- Take your medications with high-calorie fluids.
- Eat foods at room temperature.
- Avoid spicy foods or foods with strong odors.
Many newer radiation techniques are being used and studied to find more effective treatments for cancer. Some of the therapies are described below.
- radiation and chemotherapy in combination
Depending upon the particular type of cancer, physicians may choose to combine radiation with chemotherapy. Radiation may help to shrink tumors before surgery, for example, and chemotherapy may be used afterward to kill cancer cells not removed by surgery. Alternately, chemotherapy and radiation may be given at the same time. Research is being conducted in this area.
- intraoperative radiation
Intraoperative radiation is the use of radiation during surgery to treat cancerous tumors or other forms of cancer. This treatment decreases the area of affected tissue because a larger dose of radiation can be used. For some people, intraoperative radiation improves the outcome of their treatment. Intraoperative radiation may be used in addition to external radiation.
- stereotactic radiation
The use of stereotactic irradiation has added an important treatment modality to the area of brain cancer treatment. Stereotactic irradiation is the use of a single high dose of radiation sent into the diseased tissue with very narrow beams of radiation. The two main forms of stereotactic irradiation are linear acceleration and cobalt60 systems (Gamma Knife). The precision, as well as the lower amount of invasiveness offered by stereotactical surgical procedures has been shown to lower the length of hospital stays and the associated costs for certain brain cancers and conditions.
- particle radiation therapy
Particle radiation therapy is the use of higher-energy radiation particles in cancer therapy. It may work well to treat tumors that recur after being removed, or tumors that cannot be treated through surgery.
- three-dimensional (3D) conformal radiation therapy
Before the development of computed tomography (CT), exact targeting of a lesion or tumor for radiation therapy was difficult. CT provided a 2-dimensional means of visualizing the treatment area. However, a 3-dimensional visualization is necessary to define all borders of the lesion or tumor for the most precise treatment planning and implementation.
Protocols and techniques for three-dimensional conformal radiation therapy have been developed. This type of therapy may help the cancer care team visualize and treat tumors in a more precise way than ever before.
- thermoradiotherapy (hyperthermia)
The use of elevated temperatures at the site of treatment has been shown experimentally to improve the response of certain cancers to other forms of radiotherapy, as well as to chemotherapy.
Because of the difficulty in delivering adequate doses of heat to tissues located deep inside the body, hyperthermia is most often used to treat melanoma (a type of skin cancer) and breast cancer.
This type of radiation therapy involves using antibodies "tagged" with a special substance. These tagged antibodies recognize tumor cells and bind with them. By doing so, the antibodies bring cancer medication in contact with the tumor. Radioimmunotherapy may be helpful in treating cancer that has spread to other parts of the body.
- intensity-modulated radiation therapy (IMRT)
Similar in concept to 3D conformal radiation therapy, intensity-modulated radiation therapy, or IMRT, uses varying intensity within individual radiation beams in order to achieve "organ sparing" treatment (minimizing the amount of radiation to normal tissues surrounding the area being treated).
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