Breast Radiotherapy
A local treatment that lowers the risk of disease returning after surgery, usually given over a few weeks.
Why radiotherapy is used
- Breast radiotherapy is most often given after surgery (lumpectomy or mastectomy) to lower the risk of disease returning in the breast or chest wall.
- It may sometimes include the nearby lymph nodes if needed.
- The intent is usually curative and complementary to surgery; your doctor decides how much is needed based on the tumor type and surgical findings.
The area being treated
- The remaining breast after lumpectomy, or the chest wall after mastectomy.
- In some cases the lymph node areas around the collarbone or under the arm are treated.
- An extra focused dose (a "boost") may be given to the original tumor site.
Preparing for CT simulation
- At planning you lie on your back with the arm raised above the head on a dedicated support.
- You may be asked to do simple exercises to improve shoulder range of movement before starting.
- For left breast treatment we may use a breath-hold technique to move the heart away from the beam — the team will show you how and practice with you.
Positioning & immobilization
- An inclined breast board is used to hold the body and arm in the same position every day.
- Keeping the identical position ensures treatment accuracy and protects the heart and lung as much as possible.
- Tell the team about any shoulder pain or difficulty raising the arm so we can help you stay comfortable.
How your treatment is planned
- Your doctor outlines the breast or chest wall and the areas to treat, and marks the heart and lung to protect them.
- The plan is designed to cover the area evenly with the lowest possible dose to the heart (especially on the left) and lung.
- The dose may be spread over several weeks or given in a shorter schedule (larger doses over fewer sessions) depending on what suits your case.
Early (acute) side effects
- Redness, dryness, and itching of the breast skin like sunburn, increasing toward the end of treatment.
- Fatigue that builds up over the weeks.
- Mild breast swelling or heaviness, and sometimes nipple tenderness.
- Some throat irritation if nodes near the collarbone are treated.
Possible late side effects
- Slight change in skin color or texture, or a minor change in breast size or firmness.
- Shoulder stiffness or mild ache — movement exercises help prevent it.
- Arm swelling (lymphoedema) is less common, especially if nodes were treated — report any swelling early.
- Rare effects on the heart or lung, much reduced by modern protection techniques.
When to contact us immediately
- Fever or signs of skin infection in the breast (marked heat, painful swelling, pus)
- New shortness of breath or chest pain
- Sudden, noticeable arm swelling
- Severe ulceration or bleeding in the treated area that does not improve
If any of these appear, contact your treatment team immediately or go to the emergency department.
How to prepare
- Wear a soft, wire-free cotton bra, or leave the area unpressured if that is more comfortable.
- Use the moisturizer your team recommends, and avoid perfumes and deodorant on the treated area.
- Avoid direct sun on the area, and protect it with sunscreen in future.
- Do the recommended shoulder exercises to keep your movement supple.
Questions to ask your doctor
- Will my treatment include the lymph nodes or only the breast?
- How many sessions are in my plan, and is it a short or extended schedule?
- Will we use breath-hold to protect my heart?
- What is the best skin care for me during treatment?
- What is my risk of arm swelling and how can I prevent it?
Important notice
This platform is for explanation and education only and does not replace medical advice. Your treating physician is the final source of truth for your condition and treatment plan. Do not make any treatment decision based on this content alone.