# Radiotherapy for Breast Cancer: Side Effects & NHS Guide > Source: https://breastcancer-charity.org/about-breast-cancer/breast-cancer-radiotherapy/ > A UK guide to radiotherapy for breast cancer: what to expect, side effects, skin care and NHS treatment schedules. Reviewed against NHS and WHO guidance. ## What is radiotherapy for breast cancer? Radiotherapy for breast cancer uses carefully targeted, high-energy X-rays to destroy cancer cells that may remain after surgery. According to NHS guidance and Cancer Research UK, it is a standard component of curative treatment for most women who have breast-conserving surgery (lumpectomy) and for selected patients after a mastectomy. The primary goal of post-operative radiotherapy is to eradicate any microscopic cancer cells in the breast tissue, chest wall, or regional lymph nodes, thereby significantly reducing the risk of local cancer recurrence. Modern NHS radiotherapy employs advanced computerised planning (such as 3D conformal radiotherapy or Intensity-Modulated Radiotherapy — IMRT) to shape radiation beams precisely to the target area while minimizing exposure to surrounding healthy organs, including the heart and lungs. Treatment is delivered by specialist radiographers in dedicated hospital radiotherapy departments. This page provides desk-assessed educational information aligned with NHS and Royal College of Radiologists protocols. Who this guide is NOT for: patients seeking personal medical prescriptions, urgent emergency care, or individual treatment decisions — always consult your clinical oncology team for personal treatment advice. ## When is radiotherapy recommended by NHS specialists? NHS clinical oncologists recommend radiotherapy based on several factors, including the type of surgery performed, the size and stage of the tumour, surgical margin status, and whether cancer cells were found in the armpit lymph nodes. Key indications include: - After Breast-Conserving Surgery (Lumpectomy): Recommended for almost all patients to treat remaining breast tissue and lower local recurrence rates from ~30% down to under 5%. - After Mastectomy (Post-Mastectomy Radiotherapy - PMRT): Recommended if the tumour was larger than 5 cm, if cancer was present near surgical margins, or if cancer spread to four or more lymph nodes in the axilla. - Regional Lymph Node Irradiation: Directed at the axilla (armpit) or supraclavicular area (above the collarbone) if lymph nodes are involved. - Boost Radiotherapy: An extra focused dose delivered specifically to the original tumour bed for younger patients or those with higher-grade disease. ## What happens during a radiotherapy treatment schedule? Before daily sessions begin, you attend a planning appointment called a simulation. During simulation, a specialized CT scan maps your anatomy in 3D. Radiographers place tiny permanent ink dots (tattoos) the size of a pinhead on your skin to ensure precise millimeter alignment for every daily session. Under current NHS FAST-Forward trial standards, standard external beam radiotherapy for early breast cancer is typically delivered in 5 daily doses (fractions) over one week, or 15 daily doses over three weeks (Monday to Friday). Each individual treatment session lasts approximately 10 to 15 minutes, though the machine delivers radiation for only a few minutes. You lie still on a treatment couch while the linear accelerator rotates around you. The treatment is completely painless, similar to having a standard diagnostic X-ray. For left-sided breast cancer, NHS units routinely use Deep Inspiration Breath-Hold (DIBH). You take a deep breath and hold it for 20 seconds during beam delivery. This moves the heart back and away from the chest wall, shielding cardiac muscle from radiation exposure. ## What side effects can radiotherapy cause and how are they managed? Radiotherapy side effects are mostly localized to the treated area and build up gradually during treatment. Common short-term side effects include: - Skin Reactions: The skin on the treated breast or chest wall may become red, dry, itchy, or sore (similar to sunburn). In some cases, skin peeling (dry or moist desquamation) occurs in skin folds. - Fatigue: Radiation fatigue is a progressive tiredness that can persist for several weeks after treatment finishes. - Breast Swelling & Sensitivity: The breast tissue may feel heavy, swollen, or tender during and immediately after the course. - Ache or Stabbing Pains: Shooting sensations or mild muscle aches in the chest wall or shoulder are common as tissue heals. NHS radiographers recommend caring for your skin by washing with lukewarm water and mild, unperfumed soap, patting skin dry gently, applying recommended unperfumed moisturizers (such as aqueous cream or R1/R2 lotion), wearing loose cotton clothing, avoiding tight underwired bras, and keeping treated skin out of direct sunlight. Long-term (late) side effects are rare but can include slight firmness or shrinkage of the treated breast, small visible red blood vessels (telangiectasia), mild rib tenderness, or a slight increase in lymphoedema risk if armpit nodes were irradiated. Your oncology team monitors you regularly to manage any long-term changes. ## Frequently asked questions Does radiotherapy make you radioactive? No. External beam radiotherapy leaves zero radiation in your body after the machine stops. You can safely touch, hug, and be around children, pregnant women, and family members immediately after every session. Can I drive myself to radiotherapy appointments? Most patients can drive themselves to daily appointments. However, as treatment progresses and fatigue builds up, you may prefer to arrange a lift or use hospital transport services if offered. When can I swim or use hot tubs after radiotherapy? You should avoid swimming pools, sea swimming, and hot tubs until any skin reaction has completely healed and your radiographer or oncologist confirms your skin barrier is fully restored. What should I wear during radiotherapy treatment weeks? Wear soft, loose-fitting cotton clothing and soft crop tops or bra-lets without underwires to minimize friction against treated skin. Will radiotherapy cause hair loss on my head? No. Radiotherapy only causes hair loss in the specific area being treated (such as underarm hair). It does not cause hair loss on your head unless radiation is specifically directed to the brain. Clinical sources - [Radiotherapy for breast cancer](https://nhs.uk) - [FAST-Forward trial radiotherapy schedule](https://cancerresearchuk.org) - [Royal College of Radiologists breast radiotherapy guidelines](https://rcr.ac.uk) This content is for educational purposes and does not constitute medical advice. Always consult a qualified healthcare professional for personal medical guidance. --- Breast Cancer Charity — an initiative of World Aid Network. Donate: https://breastcancer-charity.org/donate/