Radiation Therapy to the Breast or Chest Wall

This information will help you prepare for radiation therapy to your breast or chest wall, including what to expect before, during, and after your treatment. You will also learn about side effects and how to care for yourself during your treatment.

You will be getting external beam radiation to treat the cancer. A beam of radiation is directed to the tumor site from a treatment machine. The beam passes through the body and destroys cancer cells in its path.

Radiation can be given to your breast after surgery or a lumpectomy or to your chest wall after a mastectomy. You can also have radiation therapy to the lymph nodes near your collarbone or under your arm.


Before you begin your treatment, you will have a treatment planning procedure called a simulation. This is done to make sure that:

  • Your treatment site is mapped out
  • You get the right dose of radiation
  • The dose to nearby tissues is as small as possible

During your simulation, you will have x-rays and your skin will be marked. These marks identify the area that will be treated.

Your simulation will take 60 to 90 minutes. Both male and female therapists will participate in your simulation.

Preparing for your simulation

There is no special preparation needed for your simulation. You may eat and drink as you normally would.

During your simulation, you will be lying with your arm raised above your head for a long time. If you think you will be uncomfortable lying still in this position, bring ibuprofen (Advil®) or your usual pain medication to your simulation. Take it when you arrive for the procedure. If you think you may get anxious during your procedure, speak with your doctor about whether medication may be helpful.

If you have recently had surgery, continue to do your arm exercises. This will help ensure that you are able to raise your arm to the position needed during your simulation.

Day of your simulation

Dress comfortably. Do not wear earrings or necklaces.

When you arrive for your appointment, your radiation therapist will greet you and take a photograph of your face. This picture will be used to identify you throughout your treatment.

Your therapist will then explain the simulation to you. If you have not already signed a consent form, your radiation oncologist will review everything with you, and ask for your signature. Your therapists will not begin the simulation without your permission.

During your simulation

For your simulation, you will get undressed from the waist up and change into a gown. You may keep your shoes on. If you wear a wig, turban, or cap, you may have to remove it. Your therapists will help you lie down on a table. Depending on the treatment location and size of your breast, you may be positioned either on your stomach or on your back. If you will be lying on your stomach, your therapists will help you step up onto a high wooden platform and get into position. Regardless of the position you are in, the arm on your affected side (side where you had your surgery) will be placed above your head. Your gown will be open throughout the procedure, exposing your breast and chest. Your therapists will make every effort to ensure your comfort and privacy.

Although the table will have a sheet on it, it is hard and has no cushion. If you have not taken pain medication and think you may need it, tell your therapist before your simulation begins. Also, the room is usually cool. If you feel uncomfortable at any time, let your therapists know.

Throughout your simulation, you will feel the table move to different positions. The lights in the room will be turned on and off and you will see red laser lights on each wall. Your therapists use these laser lights as a guide when they position you on the table. Do not look directly into the red beam because it may hurt your eyes.

Although your therapists will walk in and out of the room during your simulation, there will always be someone who can see and hear you. You will hear your therapists speaking to each other as they work. They will explain what they are doing, but please do not speak once they begin, because it may change your position. However, if you are uncomfortable or need assistance, tell your therapists.

To help pass the time, your therapists can play a CD for you. You may bring one of your own from home, if you wish.


If you are lying on your stomach, you will see that the table has a cutout to position your breast correctly.

If you are lying on your back, a mold may be made of your upper body to help you stay in the same position each time you receive your treatment. Your therapists will pour a warm fluid into a large plastic bag that will be sealed and placed on the table. You will lie on top of the bag, on your back, with the arm of your affected side raised above your head. The fluid will feel warm at first, but it will cool as it hardens. While it is cooling, your therapists will tape the bag to your skin so that it takes the shape of your upper body and arm. This procedure takes about 15 minutes. Sometimes a supine breast board may be used instead of the mold.

During your simulation, and every day of your treatment, you will lie in this mold, on the supine breast board, or over the cutout to help ensure you are in the correct position.

X-ray images

You will get x-rays of the area to be treated. These may be done on an x-ray machine called a simulator or on a computed tomography (CT) scan machine called an AcQ-Sim. These scans are used only to map your treatment. They are not used for diagnosis or to find tumors.

During the scan, you will hear the machines as they are turned on and off. Even if the noise seems loud, your therapists will be able to hear you if you need to speak with them. It will take about 45 minutes to get your x-rays.

After the x-rays are done, a staff member from the physics department will take a measurement of your breast. This is used to help ensure the accuracy of your treatment plan.

Skin markings (tattoos)

Your therapists will draw on your skin with a felt marker. Then, they will make permanent skin markings, called tattoos, with a sterile needle and a drop of ink. The sensation of getting one feels like a pinprick. The tattoo marks are no bigger than the head of a pin. You will receive 5 to 7 tattoos across your upper body. The felt marking can be washed off after your simulation. The tattoos are permanent and will not wash off. If you are concerned about receiving tattoos as part of your radiation treatment, talk with your doctor.

After the tattoos are made, your therapists will take several photographs of you in your simulation position. The photographs and tattoo marks will be used to position you correctly on the table each day of your treatment.

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After Your Simulation

Treatment planning

At the end of your simulation, we will make an appointment for your set-up procedure. This is the final appointment before your treatment begins.

During the time between your simulation and your set-up procedure, your radiation oncologist will work with a team to plan your treatment. They will use your simulation x-rays and CT scan to plan the angles and shapes of your radiation beams. They will also determine the dose that your body will receive. The details are carefully planned and checked. This takes between 5 days and 2 weeks.

Treatment scheduling

At the end of your simulation, your therapist will ask you what time of day you would like to have your treatments. We will try to give you the time you like. However, we need a 2-hour window because the time you prefer may not be open. We will move you to your preferred time slot once it becomes available. Please know that we will do our best give you the appointment time that you want as soon as we can.

Radiation treatments are given daily, Monday through Friday, for about _______ weeks. You must come in every day for your treatment. Treatment may not be as effective if you skip or miss appointments. If additional time is needed due to unforeseen circumstances, your radiation oncologist will tell you. You will be in the department for about 60 minutes each day. If you need to change your schedule for any reason, please speak with your radiation therapist.

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Set-up Procedure

Before your first treatment, you will be scheduled for a set-up procedure. This generally takes about 1 hour. If pain medication was helpful during simulation, you may want to take it before this procedure.

When you come for your procedure, you will be shown to the dressing room and asked to change into a gown. Your therapists will bring you to the room where you will receive your treatment each day. They will position you on the table. You will lie exactly as you were the lying day of your simulation. Special x-rays called beam films will be taken to make sure that your position and the area being treated are correct. The beam films will be repeated throughout your treatment. They are not used to see how your tumor responds to the treatment.

You start your treatment shortly after your set-up procedure, often the following day.

Vitamins and dietary supplements

Many patients ask about taking vitamins during treatment. You may take a daily multivitamin, if you wish. Do not take more than the recommended daily allowance of any vitamin. Do not take any other vitamins or any supplements without talking to your doctor. This includes both nutritional and herbal supplements.

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During Your Treatment

After you check in at the reception desk, have a seat in the waiting room. When your radiation therapists are ready for you, they will tell you to change. You will go to the dressing room, undress from the waist up, and put on a gown. You can keep your shoes on during the treatment.

When they call you for treatment, your therapists will position you as you were lying on the day of your set-up procedure, either face down, positioned on the platform over the breast cutout, or on your back, lying on your mold. One or both arms will be raised above your head. Both male and female therapists may be involved in your treatment, but every effort will be made to ensure your comfort and privacy.

Once you are positioned correctly, your therapists will leave the room, close the door, and begin the treatment. You will not see or feel the radiation, but you may hear the machine as it moves around you and is turned on and off. You will be in the treatment room for 10 to 20 minutes, depending on your treatment plan. Most of this time will be spent putting you in the correct position. The actual treatment only takes a few minutes.

Although you will be alone during the treatment, your therapists will see you on a monitor and hear you through an intercom at all times. Breathe normally during the treatment, but do not move. However, if you are uncomfortable or need help, speak to your therapists. They can turn off the machine and come in to see you at any time, if necessary.

Neither you, nor your clothes will become radioactive during or after treatment. It is safe for you to be around other people.


If you are having radiation after a lumpectomy, your initial radiation treatment will be directed to your whole affected breast for 3 ½ to 5 weeks. After that is done, you may receive an extra dose of radiation called a “boost.” The boost directs radiation to the area where your lump or cancer cells were located.

Before your boosts, your doctor will make more skin markings with a felt-tipped marker to outline the boost field. You will need to wear a shirt that you do not mind getting stained because the dye from the marker will stain your clothes. These skin markings are not permanent. Do not wash them off until your treatment is completed.

During your boost, you will receive the same amount of radiation that you got for your treatments. However, it will be aimed at a smaller area. This process involves getting another 3 to 7 treatments. There may be a break for a few days between the end of your radiation to the whole breast and the start of your boost. You may be treated on a different machine for your boost, or change positions from lying on your stomach to lying on your back.

If you are receiving radiation to your chest wall or the lymph nodes near your collarbone or under your arm, you will receive 5 to 5 ½ weeks of treatment. You may not need a boost. Your radiation oncologist will explain your schedule.

Weekly visits during treatment

Your radiation oncologist and radiation nurse will see you each week to evaluate your response to treatment. This visit will be before or after your treatments each ________________. You should plan on being in the department about 1 extra hour on those days.

During these visits, you should ask questions and discuss any concerns you have. If you need to speak with your radiation oncologist or radiation nurse any time between these weekly visits, ask the support staff or your therapists to contact them when you come in for treatment.

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Side Effects

Some people develop side effects from radiation therapy. The type and how severe they are depend on many factors. These include the dose of radiation, the number of treatments, and overall health. Side effects may be worse if you are also getting chemotherapy. Below are the most common side effects of radiation therapy to the breast or chest wall. You may have all, some, or none of these.

Skin and hair reactions

During the course of radiation therapy, your skin and hair in the area being treated will change. This is normal and expected. After 2 to 3 weeks, your skin will become pink or tanned. As treatment goes on, it may become bright red or very dark. It may also feel dry and itchy, and it may look flaky. The skin reaction from radiation therapy generally peaks 1 or 2 weeks after radiation therapy ends, and begins to heal after that point.

You may also notice a rash, especially in any area where you have had previous sun exposure. Although this may be a side effect of treatment, a rash could also be a sign of infection. If you develop a rash at any time during your treatment, tell your doctor or nurse.

Sometimes, the skin in sensitive areas, such as under your breast or arm and near your collarbone, may blister, open, and peel. If this happens, tell your doctor or nurse. Your nurse will apply special dressings or creams and teach you how to care for your skin. Your doctor may stop your treatment until your skin heals. This skin reaction sometimes becomes more severe during the week after treatment is done. If this happens, call your doctor or nurse. Your skin will gradually heal after your treatment is completed, but this often takes 3 to 4 weeks.

You may lose some or all of the hair under your arm. The hair will usually grow back 2 to 4 months after your treatment is completed.

Below are guidelines to help you care for your skin during treatment. Follow these guidelines until your skin gets better. These guidelines refer only to the skin in the area being treated.

Keep your skin clean

  • Bathe or shower daily using warm water and a mild unscented soap, such as Neutrogena®, Dove®, baby soap, Basis®, or Cetaphil®. Rinse your skin well and pat it dry with a soft towel.
  • When washing, be gentle with your skin in the area being treated. Do not use a washcloth or a scrubbing cloth or brush.
  • The tattoo marks you received before your treatment are permanent and won’t wash off. You may get other markings during treatment such as an outline of your treatment area with a purple felt-tipped marker. You can remove these markings with mineral oil when your therapists say it’s okay.
  • Do not use alcohol or alcohol pads on your skin in the area being treated.

Moisturize your skin often

  • Start using a moisturizer when you begin treatment. This can help to minimize any skin reaction. Over-the-counter moisturizers you can use include Eucerin®, Aquaphor®, or calendula. You may be prescribed mometasone furoate, a steroid cream, either at the start or during your radiation therapy to treat itchy skin. There are a number of other products that are also good to use, and your nurse may recommend one of these to you. Use only one at a time unless your nurse tells you to use more.
  • Apply the moisturizer 2 times a day. Your nurse will tell you if you need to do it more or less often.
    • If your radiation treatment is in the morning, apply the moisturizer:
      • After your treatment
      • Before you go to bed
    • If your radiation treatment is in the afternoon, apply the moisturizer:
      • In the morning, at least 4 hours before your treatment
      • Before you go to bed
    • On the weekends, apply the moisturizer:
      • In the morning
      • Before you go to bed
  • Do not wash off the moisturizer before your treatment. Your skin could become irritated.

Avoid irritating the skin in the area being treated

  • Wear loose-fitting cotton undergarments. Do not wear underwire bras or any tight clothing that will rub against your skin.
  • Use only the moisturizers, creams, or lotions that are recommended by your doctor or nurse.
  • Do not use makeup, perfumes, or powders in the area being treated.
  • You can use nonaluminum-based deodorant on intact skin in the area being treated. Stop using it if your skin becomes irritated. Examples of these deodorants include Tom’s of Maine®, Arm and Hammer Essentials Solid Deodorant®, cornstarch, or crystal deodorants.
  • Do not shave the treated skin. If you must shave, use only an electric razor. Stop if the skin becomes irritated.
  • Do not put any tape on the treated skin.
  • Do not let your treated skin come into contact with extreme hot or cold temperatures. This includes hot tubs, water bottles, heating pads, and ice packs.
  • If your skin is itchy, do not scratch it. Ask your nurse for recommendations on how to relieve the itching.
  • If you have no skin reactions during your treatment, you can swim in a chlorinated pool. However, be sure to rinse off the chlorine right after getting out of the pool.
  • Avoid tanning or burning your skin during and after treatment. If you are going to be in the sun, use a PABA-free sunblock with an SPF of 30 or higher. Also, wear loose-fitting clothing that covers you as much as possible.

Breast discomfort or swelling

You may have some tenderness in your breast, especially at the nipple, early in the course of your treatments, often in the first week. In addition, you may develop extra fluid in your breast that may cause sharp, stabbing sensations. Your breast or chest may feel heavy or swollen. You may also have some shoulder stiffness on your affected side. These sensations may begin within the first few days of treatment and persist for many months after your treatment is done. Below are suggestions to help you reduce this discomfort.

  • Wear soft, loose bras without an underwire. You may even find it more comfortable not to wear a bra at all.
  • Take ibuprofen as needed for pain. If you cannot take nonsteroidal anti-inflammatory drugs (NSAIDs), which include ibuprofen, you may take acetaminophen (Tylenol®) instead.
  • Do your arm exercises to relieve the stiffness in your shoulder. The wall crawl exercises are very helpful.


You may develop fatigue (i.e., lack of energy, sleepiness, weakness, and not being able to concentrate) after 2 to 3 weeks of treatment. This will gradually go away after your treatment is done, but can last for several months. There are a lot of reasons why you may develop fatigue during treatment, including:

  • The effects of radiation on your body
  • Traveling to and from treatment
  • Not having enough restful sleep at night
  • Not eating enough protein and calories
  • Having pain or other symptoms
  • Feeling anxious or depressed

Some people find that their fatigue is worse at certain times of the day. Below are suggestions to help you manage your fatigue.

  • If you are working and are feeling well, continue to do so. However, working less may help increase your energy.
  • Plan your daily activities. Pick those things that are necessary and most important to you and do them when you have the most energy.
  • Plan time to rest or take short naps during the day, especially when you feel more tired. You may also find it helpful to go to sleep earlier at night and get up later in the morning.
  • Ask family and friends to help you with shopping, cooking, and cleaning.
  • Some patients have more energy when they exercise. Ask your doctor if you can do light exercise, such as walking.
  • Eat foods that are high in protein and calories.
  • Some patients have other symptoms such as pain, nausea, difficulty sleeping, or feeling depressed or anxious. These can all increase your fatigue. Ask your doctor or nurse for help with any other symptoms you may have.

Sexual health

You may be sexually active during your treatment unless your radiation oncologist gives you other instructions. However, if you are of childbearing age, you must use contraception to prevent pregnancy during your treatment.

You may have concerns about the effects of cancer and your treatment on your sexuality. An excellent resource is the booklet Sexuality and Cancer. There are two versions available, one for men and one for women. You can get a copy of this booklet from the American Cancer Society. Call 1-800-227-2345 and tell them which version you want.

Memorial Sloan Kettering Cancer Center (MSK) has a Sexual Health Program to help patients address the impact of their disease and treatment on sexual health. You can meet with a specialist before, during, or after your treatment.

  • Female Sexual Medicine and Women’s Health Program: call 646-888-5076 for an appointment
  • Male Sexual and Reproductive Medicine Program: call 646-888-6024 for an appointment

Emotional health

The diagnosis and treatment of cancer can be a very stressful and overwhelming event. You may feel depressed, anxious, confused, afraid, or angry. You may have strong feelings about any permanent changes. These changes can have an impact on your emotional well-being. Help is available for you at any time. If you would like counseling, your nurse can give you a referral to see a social worker, psychiatrist, or counselor.

The MSK Resources for Life After Cancer (RLAC) Program provides support services after your treatment is finished. To learn more about these services, call 646-888-8106.

Also, you may find it comforting to speak with a cancer survivor or caregiver who has been through a similar treatment. Through our Patient-to-Patient Support Program, you have a chance to speak with former patients and caregivers. To learn more about this service, please call 212-639-5007.

Signs and symptoms of depression

Depression can occur at any time when you have a serious illness. It is important to recognize the symptoms. Help is available to treat and manage it. The signs of depression include:

  • Change in sleep patterns (such as too little or too much sleep)
  • Change in appetite or eating patterns (such as eating too little or too much)
  • Feeling sad, down, or hopeless
  • No longer enjoying activities that you once liked
  • Having thoughts or plans of suicide or hurting yourself
  • Feeling very tired or having little energy
  • Feeling slowed down
  • Feeling anxious or restless
  • Having trouble focusing on tasks or activities, such as reading

If you have any of these symptoms and they last more than 2 weeks, tell your doctor, nurse, or social worker.

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After Your Treatment

Please be sure to keep your follow-up appointments with your radiation oncologist. He or she will evaluate your response to treatment. You may have blood tests, x-rays, and scans during these visits. Before coming, write down your questions and concerns. Bring this and a list of all your medications. If you are running low on any medication you need, let your doctor know before you run out. You can also call your doctor or nurse at any time after your treatment is completed, or in between follow-up visits, if you have any questions or concerns.

You may have had the opportunity to meet with a dietitian and social worker during your treatment. These specialists remain available to assist you in person or via telephone during and after your radiation therapy. Your social worker can also recommend support groups that can be of benefit to you.

At some point, your doctor may transfer your care to a survivorship nurse practitioner (SNP). The SNP is a member of the MSK Breast Cancer team and works closely with your doctor. As your needs decrease, your follow-up care may be transferred from MSK to your local physician. The timing for this will depend on your particular cancer and your treatment. It usually occurs about 10 years after treatment.

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