Information alert

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This information has been written for patients who are having radiotherapy to the breast or chest wall area. It explains what the treatment involves, describes side-effects you may experience during and after treatment, and how best to cope with them.

We understand this is a worrying time for patients and their families, and we hope this information can help to answer any questions you have. If you have any questions about the treatment or information provided here, please speak to the team looking after you.

We want to involve you in all the decisions about your care and treatment. If you decide to go ahead with treatment, by law, we must ask for your consent and will ask you to sign a consent form. This confirms that you agree to having the procedure and understand what it involves. 

Staff will explain all of the risks, benefits and possible alternatives before they ask you to sign a consent form. If you are unsure about any aspect of your proposed treatment, please do not hesitate to speak to the team looking after you.

During your time with us we aim to provide the highest standards of care and support you in your decisions regarding your treatment. We will respect your dignity, individuality and personal preferences.

Your care will be managed and given by therapeutic radiographers, doctors and nurses. You will meet both male and female healthcare professionals. If you have any concerns about this, please talk to the radiographers about it. We try to be sensitive to your needs, so please do not hesitate to discuss things with the team caring for you.

If you are of an age where you can get pregnant (12 to 55 years old) and capable of becoming pregnant (you have a womb), you will be asked to confirm that you are not pregnant. 

You must tell the staff immediately if there is any chance of you being pregnant at any time during your treatment. You should not become pregnant for at least four months after radiotherapy. 

If you have any further questions or concerns about this please talk to your clinical oncologist, consultant radiographer or specialist nurse involved in your care.

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Radiotherapy appointments:

All take place in the Radiotherapy Department, basement floor, main UCH hospital building.

Proton Beam Therapy appointments:

All take place in the Proton Beam Therapy Department, floors B3 and B4, Grafton Way Building.

Radiotherapy is the specialised treatment of cancer (and some other diseases) using high energy radiation beams. These can either be x-rays (also called photons), electrons or protons. X-rays and electrons are delivered from a machine called a linear accelerator whilst protons are delivered from a machine called a cyclotron. The most appropriate treatment for you will be decided by your clinical oncologist and discussed with you.

Radiotherapy works by damaging cancer or tumour cells in the part of the body being treated. The radiation stops the cells from dividing and growing. Radiotherapy can also damage nearby normal cells. The normal cells are more likely to recover from the effects of the radiation than the cancer or tumour cells. The clinical team take great care to reduce the radiation dose to a person’s healthy cells.

Radiotherapy does not hurt, and it will not make you radioactive. You will be completely safe to be around family, friends and pregnant women. You will feel nothing from the treatment and the machine will not touch you. It is rather like having an ordinary x-ray. The most important thing is for you to lie very still for treatment. 

Treatment is given daily Monday to Friday, including Bank Holidays. A course of treatment will last one to four weeks. Your treatment schedule will be decided by your doctor or consultant breast radiographer and confirmed on your first treatment visit to the radiotherapy or proton beam department.

Before beginning radiotherapy or proton beam therapy, your treatment must be carefully planned. Your first visit will be to the radiotherapy or proton planning pre-treatment department. At this appointment you will have a CT scan, to gain information of the area to be treated whilst you are lying in the treatment position. 

Before your scan, it is important that your surgical scars are fully healed and there is no swelling (inflammation) of your breast. If you have any questions about this, please call the radiotherapy department on 020 3447 3700 / 3701 and ask to speak to the radiotherapy pre-treatment radiographers. 

It is also important that you are able to raise your arms comfortably over your head with your arms/elbows facing outwards. If you are unable to do this, due to surgery in your armpit or a pre-existing shoulder problem, you may need at least one to two weeks to practice this position. You can get exercise advice from your specialist breast nurse. If you have any questions about this, please call the radiotherapy department on 020 3447 3700 / 3701 and ask to speak to the radiotherapy pre-treatment radiographers. 

When it is time for your scan the radiographers will take you in to the CT scanner room. The radiographers are there to explain the procedure and to answer any questions you may have. You will be asked to change into a hospital gown and remove all clothing down to your waist. The radiographers will ask you to lie on the CT couch on a specialised board. They will lower the gown and ask you to raise your arms above your head. There are arm supports to help you maintain this position. It is important to lie still during the planning procedure so that accurate measurements can be taken. Please tell the radiographers if you are uncomfortable and they will adjust your position. The entire planning procedure will take about thirty minutes.  

Using a felt-tip pen, the radiographers will place some temporary marks on your skin and take some measurements. These are for reference only and can be removed when you go home. Sticky wire will be placed around the treatment area and at various landmarks of the treatment area. The radiographers will then leave the room to perform the CT scan. 

You will feel the bed move in and out of the scanner. You will pass through the scanner a number of times. The radiographers will be watching you the entire time. When the scan is done, and the radiographers have checked the images they will re-enter the room. The radiographers will then mark several specific points (also called tattoos) on your skin. These are alignment marks to ensure each treatment is accurate. The marks are permanent and are done by placing ink on the skin and then gently scratching the surface of your skin with a fine needle.

You won’t feel anything during the scan. All we ask is that you lie still and breathe normally. After the scan is completed, you will be free to leave. Before you go, you will be given an appointment card with the date and time for your next visit, which will be your first treatment.

If you are having treatment to the left breast/chest wall area or the lymph nodes beneath your breast bone (internal mammary nodes), you will be asked to attend an additional planning appointment one to two days before your planning CT scan.We use this session to teach you a breathing technique called deep inspiration breath hold (DIBH). Treating you whilst you take and hold a deep breath will reduce the radiotherapy dose to your heart, which is located on the left side of your chest. Your radiotherapy planning CT scan will be taken with you holding your breath for about twenty seconds.

To read more about DIBH, please go to the following link:

Patients will normally receive their treatment as an outpatient. Treatment is every day, Monday to Friday, including Bank Holidays. Your clinical oncologist or consultant breast radiographer will have already told you how many treatments you will be having. The treatment radiographers will explain the procedure to you and answer any questions you may have.

For each treatment session you will be lying, on the treatment couch on the special board with your arms raised and supported above your head. The radiographers will ensure you are in the correct treatment position by aligning the tattoo marks on your chest with laser lights. They will then move the treatment machine and couch into position using your personal treatment plan. When final verbal checks have been made, the radiographers leave the room. To give you the best treatment you will be treated from several different angles. The treatment machine will move around you but will not touch you. You will not feel anything. All we ask is that you keep still. The radiographers will be watching you at all times on a closed-circuit television.

Treatment time is dependent on whether you are having radiotherapy with photons or with protons. If you are having photon treatment, then each session takes approximately 15-20 minutes. If you are receiving proton beam therapy the treatment may be a little longer and can last up to 45 minutes. The treatment radiographers will confirm with you how long the treatment is expected to take before they start.

If we are treating your left breast, left chest wall area, or lymph nodes beneath your breast bone, and you had your planning CT scan whilst using the breathing technique called deep inspiration breath hold (DIBH), you will also be asked to do this during your treatment sessions. For each treatment session, this will involve several breath-holds. 

To read more about DIBH, please go to the following link:

There will be some side effects which will gradually appear during your course of treatment. These effects will vary from patient to patient. There are side effects occurring during treatment, some happening soon after treatment, and some appearing months or years after radiotherapy.

The risk and severity of side effects occurring will depend on the dose of radiotherapy or proton beam therapy given and the exact area which receives treatment. Your doctor, or consultant radiographer, will discuss the risks of treatment with you before you sign a consent form. However, there will still be plenty of opportunity to talk about anything that you feel needs further discussion. 

The main side effects that occur during treatment are:

Skin changes

The skin in the area being treated will gradually change colour. Your skin will gradually become pink /red or darker, depending on your skin colour. You may get some dry peeling of the skin in the treatment area, which may become itchy. Some patients may experience peeling of the skin in the armpit or under the crease of the breast which can be sore. 

During treatment we advise that you wash normally using warm water and the soap products you would normally use. Gently pat your skin dry with a soft towel. 
Radiotherapy skin reactions cannot be prevented, but to minimise any skin irritation we recommend using a moisturiser of your choice. Use the moisturiser frequently and gently smooth it on to your skin until it is absorbed. You do not need to wipe the moisturiser off before treatment, but please do not apply moisturiser immediately before treatment.

If your moisturiser starts to irritate your skin or your skin peels and is sore, stop using the moisturiser and let your team know. They will refer you to the radiotherapy review team for appropriate skin care. If you do not currently use a moisturiser then speak with your radiotherapy team and they will be able to suggest some options for you. 

How can I help myself?

By following this advice, you may keep your skin in good condition and feel more comfortable. This only applies to the skin in the area being treated.

  • Wear loose-fitting, natural fibre clothing, such as cotton or silk, next to the skin.
  • Avoid tight or underwired bras as these may rub your skin and make it more sore. During treatment you may find cotton crop tops, camisoles or vests are better than bras as they do not rub.
  • You can continue to use the deodorant you normally use unless it irritates your skin. If your skin becomes too sore or peels, stop using deodorant. 
  • You may go swimming if your skin has fully healed from surgery and is not peeling from treatment. Always shower immediately afterwards to wash off any chlorine and apply moisturiser. Please stop swimming if it irritates your skin.
  • Do not apply any cosmetics, perfumes or aftershaves to the skin in the treated area.
  • Avoid the use of plasters in the area being treated.
  • Avoid rubbing or scratching the skin in the treatment area.
  • Avoid extremes of temperature such as heating and cooling pads.
  • Avoid sun exposure and protect the area from direct sunlight. Continue to protect the area from the sun for at least one year after you have finished treatment. Because your skin will be more sensitive, always use a sunscreen with a high sun protection factor.
  • Do not wet shave or use hair removal creams under your arm on the treated side as these can irritate your skin. You may use an electric shaver for removing hair in the treatment area during your radiotherapy unless it is found to irritate the skin. 
  • Do not smoke. Smoking may reduce the effectiveness of treatment and can often make the side effects much worse. If you need help to stop smoking, please ask as we offer a stopping smoking service here.
  • To improve your overall health, try to drink 6-8 glasses of water a day and eat a nutritionally well-balanced diet.

Feeling sick

Feeling sick is unusual during treatment, although some patients, particularly those who are receiving chemotherapy, may feel sick and sometimes be sick. This can be well controlled with anti-sickness medication. If you are experiencing any symptoms, please tell us. 


Tiredness is a very common side effect of radiotherapy and proton beam therapy. You may feel more tired than usual and have less energy, both during and after treatment. Do not worry, this is normal. It is usually a combination of travelling to hospital every day, the side effects of treatment, coping with a diagnosis of a tumour and continuing with normal life.

We recommend that you listen to your body. Do as much as you feel you can and rest when you need to. However, gentle exercise has been found to improve fatigue levels in patients and we would recommend walking as a good form of exercise. Please tell us if you are finding things difficult, as we will be able to offer practical advice and information.

Hair loss

Many patients are worried that radiotherapy will cause hair loss to their head. Please be assured that you will not lose any hair on your head from the radiotherapy, and it will not prevent regrowth of hair after chemotherapy. Radiotherapy is a very localised treatment and only affects the area being treated. You may find that the hair under the arm on the affected side will stop growing and fall out during treatment. After treatment you may experience less hair growth in that area.

At your first treatment appointment the radiographers will discuss the treatment with you and explain any possible side effects you may experience. They will see you every day and ask how you are and how you are feeling. During treatment you will be assessed on a weekly basis by the radiotherapy review team and/or the clinical fellows who will monitor your side effects and review your progress.

Late side effects incurred during treatment can appear to develop many months or years after radiotherapy has finished. They are the hardest to accurately predict and, unfortunately, when they do occur, they are usually permanent. Your doctor or consultant breast radiographer will discuss the possibility of these late side effects with you, at the time you sign your treatment consent form. Possible late side effects may include:

Radiotherapy to the breast alone

You may experience swelling and tenderness in the treated breast in the months following radiotherapy. You may also experience sharp pains and twinges on the treated side. This is normal and is due to your body healing following the surgery and radiotherapy. It should disappear in time, but if you are uncomfortable, please see your GP.

A few patients may find the treated breast is smaller or slightly different in shape after treatment. This is caused by fibrosis or thickening of the underlying breast tissue. In a small number of cases there may be thickening of the skin. The skin may feel “leathery” due to a loss of elasticity and suppleness. 

Some women may experience pigmentation of the skin in the treated area. This may vary from light to a darker brown.

Approximately 1% of patients may develop dilation of the tiny blood vessels in the skin, called telangiectasia. Although this is not painful, it can cause red or purple areas on the treated skin, which look like spidery marks. Dilation occurs because the capillaries are compensating for the destruction or narrowing of other blood vessels, as a result of the radiotherapy.

Less than 1% of patients may develop weakening of the underlying ribs on the treated side. This may increase the risk of a fracture in later years.

When treating the breast or chest wall it is not possible to avoid the underlying lung completely. A small amount of lung is treated. It is rare for this to cause any problems for the majority of patients. A few patients may develop a dry cough which will improve in time. In less than 1% of patients, the symptoms may include a cough and shortness of breath upon exertion, or changes on a chest X-ray. 

When treating the left breast or chest wall area, a small portion of the heart may be in the treatment field. This may lead to an increased risk of heart (cardiac) problems in later years for 1% of patients. The dose to the heart is greatly reduced by treating patients whilst they take and hold a deep breath. 

Radiotherapy to nodal areas

Some patients require radiotherapy to one or more nodal areas in addition to their breast or chest wall. This may be the lymph nodes under the arm (axilla), above the collar bone (supraclavicular fossa), or along the breast bone (internal mammary chain). Your doctor or consultant radiographer will tell you which sites require treatment. 

Treating nodal areas can increase the risk of lymphoedema developing in later months or years. Approximately 10% of these patients will develop some degree of swelling. The swelling can occur at any time.

When treating the lymph nodes above the collar bone, there is a small risk of shoulder stiffness. This is due to scarring of the tissue around the shoulder joint. Regular arm exercises will help. There is a very small risk that you may develop weakening of the collarbone on the treated side. This may increase the risk of a fracture in later years. A very rare side effect is called Brachial Plexus Neuropathy. This is caused by damage to the nerves around the area treated and can lead to pain, weakness, altered sensations (such as numbness and pins and needles), and restricted movement to the arm and hand on the treated side. It occurs in less than 1% of patients. 

Second malignancy

Less than 1% of people who have received treatment for one particular tumour may develop another type of tumour in the treated area some years later. The radiotherapy doctors will discuss this risk if it is relevant to you.

Lymphoedema is when an area of the body swells because the lymph fluid is not draining normally. Lymphoedema can occur when the lymphatic structures are damaged. Inflammation, infection, radiotherapy and surgery can all cause lymphoedema. Most patients have some lymph nodes (glands) removed from the armpit during surgery for breast cancer. The number of lymph nodes removed can increase the risk of lymphoedema in the arm or hand on the side of the operation. Some patients may also experience lymphoedema of the treated breast.

It is advisable to follow the guidelines listed below to reduce the risk of infection and swelling to your arm on the treated side:

  • Avoid carrying heavy shopping or luggage with the affected arm.
  • Avoid allowing your arm to be used for injections or blood transfusions.
  • Do not have acupuncture on your affected arm.
  • Avoid having your blood pressure taken on the affected arm.
  • Do not use a wet razor to remove hair under your arm—use an electric razor or cream.
  • Wear gloves to protect your hand whilst working in the kitchen and garden.
  • Use insect repellent to prevent bites.
  • Protect your skin from sunburn.
  • If you cut or scratch your hand or arm, wash the area well and apply antiseptic. Cover with a plaster. If the area becomes hot, red or swollen, inform your doctor as soon as possible. You may need some antibiotics.

Lymphoedema can be treated. Talk to your doctor or consultant breast radiographer, or the radiotherapy review team if you notice any swelling, however slight. We can refer you to the lymphoedema service here at UCH. 

It is important that during radiotherapy you continue the arm exercises that you were shown after your surgery. You should continue with the exercises for a few months after radiotherapy finishes. The exercises help to regain shoulder movement and help to prevent joint stiffening. If you have not been shown how to do the exercises or are having difficulty with moving your arm, please speak to the team looking after you.

If you have had a mastectomy without a reconstruction, you will have been given a temporary soft prosthesis after your operation (also known as a cumfee). You can continue to wear the cumfee during your treatment, however you may find wearing a bra uncomfortable. If possible, avoid wearing a bra when you are at home to prevent friction in the treatment area, which will help reduce the skin reaction.

You may have been given a silicone breast prosthesis. It is advisable not to wear this during the treatment as it may cause skin irritation. If you have not been fitted with a silicone prosthesis this can be done at the hospital where you had your surgery, when radiotherapy has finished. It is advisable to wait for one month for any skin reaction to settle down. 

Advice on prostheses and bras can be obtained from your own breast care nurse or surgical appliance office at your hospital. Alternatively, the breast care nurses here can advise you on this aspect of your post-operative care.

This information deals with the physical aspects of your treatment, but your emotional wellbeing and that of your family is just as important. Having treatment can be deeply distressing for some patients. Within the radiotherapy and proton beam therapy departments there will be access and support from the radiotherapy review team, your specialist nurse, the treatment radiographers and the Macmillan information and support team. However, if you feel you require further medical or emotional support you can be referred to a variety of health professionals who can help with any worries or difficulties you may be having.

All the staff are here to make sure your treatment goes as smoothly as possible and to support you through this difficult period. We will try to help you with any questions or problems you may have.

The side effects you are experiencing will continue after treatment has finished. It is common to experience a worsening of the skin reactions for about ten to fourteen days after radiotherapy. You will be reviewed by your radiotherapy consultant four to six weeks after completing your radiotherapy or proton beam therapy. This may be a telephone or face-to-face appointment. Face-to-face appointments will be held in the UCLH Macmillan cancer Centre. 

Some patients will be discharged back to their local referring centres for symptom care and follow-up. Please feel free to contact the radiotherapy or proton beam therapy department if you are worried about your treatment side effects.

My Clinical Oncologist is:

My Consultant Breast Radiographer is:

They can be contacted on: 020 3447 2353 / 07534 011 816


Radiotherapy Reception

t: 020 3447 3700 / 3701

Radiotherapy Review Team (via Radiotherapy Reception)

t: 020 3447 3700 / 3701

Proton Beam Therapy Reception

t: 020 3456 8000 / 8001

Proton Beam Therapy Review Team (via Proton Beam Therapy Reception)

t: 020 3456 8000 / 8001

Macmillan Information and Support Radiographer

t: 020 3447 3712

Macmillan Radiotherapy Support Worker

t: 020 3447 3780

Surgical Breast Care Specialist Nurse:

t: 020 7380 9298
t: 020 3456 7890 bleep 1523

UCLH Lymphoedema Clinic Secretary: 

t: 020 7380 9325

Lymphoedema Nurse Specialist:

t: 020 3456 7890 ext 4324

Out of hours oncology advice number (available 24 hours)

m: 07947 959020

If you have any concerns that you would like to discuss in confidence, please contact our PALS (Patient Advice and Liaison Service) for information and advice.

t: 020 3447 3042 

Breast Cancer Now:

t: 0808 800 6000

Breast Cancer UK


Lymphoedema Support Network

Provides information and support for people with lymphoedema
t: 020 7351 4480

Macmillan Cancer Support 

t: 0808 808 0000 

Cancer Research UK

t: 0808 800 4040 



Young Lives vs Cancer (formerly CLIC Sargent)

t: 0300 330 0803

Shine Cancer Support

t: 07804 479413


t: 020 4541 7601

Carers UK

t: 0808 808 7777 

NHS Choices 

UCLH cannot accept responsibility for information provided by other organisations.

Page last updated: 22 May 2024

Review due: 01 May 2026