01Purpose and principlesWhat the treatment does and how it fits into care.
Adjuvant radiotherapy sterilises microscopic disease in retained breast, chest wall or regional lymphatics. The target depends on the operation and recurrence pattern, not simply the presence of a scar. Whole-breast treatment is the usual partner to conservation; partial-breast treatment is reserved for selected low-risk situations; chest-wall and nodal fields follow tumour size, margin, node and neoadjuvant evidence. The original anatomy must remain reconstructable after tissue rearrangement.
Hypofractionation delivers an effective dose in fewer visits. Current NICE guidance offers 26 Gy in five daily fractions over one week for breast or chest-wall treatment when regional nodes are not included. It specifically preserves 40 Gy in 15 fractions over three weeks as an option for factors including increased radiosensitivity or implant reconstruction. Consent covers small differences in acute effects, uncertainty in particular subgroups and techniques used to minimise heart and lung exposure.
Key points
- Offer whole-breast radiotherapy after breast-conserving surgery for invasive cancer unless a defined low-risk omission pathway is agreed; consider radiotherapy after conservation for DCIS.
- Offer postmastectomy radiotherapy for invasive cancer with macrometastatic node positivity or involved resection margins; consider it for node-negative T3 or T4 disease. Reassess both baseline and residual burden after neoadjuvant treatment.
- NICE offers 26 Gy in 5 fractions over 1 week for partial-breast, whole-breast or chest-wall radiotherapy without regional nodal irradiation after conservation or mastectomy.
- Consider 40 Gy in 15 fractions over 3 weeks for the same non-nodal settings when radiosensitivity, implant reconstruction or another factor makes the longer schedule more acceptable.
- For regional lymph-node irradiation, with or without breast or chest-wall treatment, NICE offers 40 Gy in 15 fractions over 3 weeks. The non-nodal 26 Gy in five fractions recommendation has a different target population.
- Plan from pathology and pretreatment stage, protect heart and lung, identify the tumour bed after oncoplastic surgery and counsel on skin, fatigue, oedema, fibrosis and reconstruction effects.
02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.
The residual breast contains potential microscopic disease; clips and operative notes help locate the tumour bed for any boost or partial-breast plan.
Large tumour, involved margin or nodal burden can justify treatment of skin flaps and chest wall despite removal of visible breast tissue.
Axillary, supraclavicular and internal mammary coverage depends on regional risk and must balance recurrence reduction against lymphoedema, heart and lung exposure.
Fibrosis, breast shrinkage, telangiectasia, oedema, shoulder stiffness, lymphoedema and rare cardiac or pulmonary injury may emerge after acute erythema resolves.
03Assessment before treatmentTests and checks that guide safe selection.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Postoperative pathology reviewFirst step - Why
- Define tumour size, margins, nodal burden and response that determine radiotherapy indication and fields.
- Interpretation and limitations
- Use original and post-neoadjuvant information together. A mastectomy specimen with involved margin or macroscopic nodes retains substantial locoregional risk.
- 02
Planning CT - Why
- Reproduce treatment position and contour breast or chest wall, heart, lungs and any nodal targets.
- Interpretation and limitations
- Dose-volume assessment guides breath hold, beam arrangement and whether field compromise or another technique is needed.
- 03
Tumour-bed localisation - Why
- Identify the excision cavity after standard or oncoplastic conservation.
- Interpretation and limitations
- Surgical clips, imaging and operative diagrams should agree; a scar alone can be misleading after tissue displacement.
- 04
Baseline shoulder and skin assessment - Why
- Identify positioning limitation, wound delay, infection and lymphatic morbidity before simulation.
- Interpretation and limitations
- Treat remediable restriction promptly and coordinate timing so radiotherapy starts safely without avoidable oncological delay.
04Treatment approachPreparation, options, escalation and aftercare.
01Worked case: one-week breast radiotherapyConfirm that the 26 Gy recommendation fitsFirst stepA patient has completed breast-conserving surgery for invasive cancer with clear margins and requires whole-breast radiotherapy without nodal irradiation.+
- 1In this illustrative case, a 48-year-old has a healed left-sided conservation wound after excision of a 22 mm invasive cancer with clear radial margins and negative sentinel nodes. The postoperative team confirms an indication for whole-breast treatment and no regional nodal target. Age and other findings are considered explicitly; the older low-risk omission pathway is not assumed to apply.
- 2Assessment finds no implant reconstruction, significant radiosensitivity diagnosis or positioning limitation that would favour the longer schedule. The patient compares the relevant options and accepts 26 Gy total in five fractions over one week. The team explains that the total is divided into five treatments, not 26 Gy at each attendance.
- 3Planning CT and a rehearsed deep-inspiration breath-hold technique allow the left-breast target and heart/lung constraints to be checked. The tumour bed is identified from the operative and clip records, and any separate boost decision is documented from local-recurrence risk rather than silently included in the five-fraction total.
- 4All five prescribed whole-breast fractions are delivered. At early review she has mild erythema and fatigue but no wound breakdown or respiratory symptoms. The care team records these actual effects and gives an accessible contact route if symptoms worsen.
- 5The treatment summary states that no regional nodes were irradiated and records the delivered course, toxicity and follow-up responsibility. She can describe the advice for skin care and later swelling, pain or breathlessness. This completed example does not transfer the non-nodal prescription to a patient requiring regional-node irradiation.
02Postmastectomy pathwayDo not equate mastectomy with no radiotherapyMastectomy pathology shows multiple macroscopic positive nodes after primary surgery.+
- 1Review tumour size, margins, number and size of nodal deposits and any extranodal extension at the multidisciplinary meeting.
- 2Offer postmastectomy radiotherapy for invasive cancer with macrometastatic positive nodes or involved resection margins: an involved margin is an indication even without positive nodes. Consider it for node-negative T3 or T4 disease, while most people with low-risk node-negative disease do not need it. Discuss locoregional benefit, heart and lung exposure, lymphoedema and reconstruction effects before the patient chooses treatment.
- 3Choose fields and fractionation separately. NICE offers 40 Gy in 15 fractions over 3 weeks for regional-node irradiation, with or without breast or chest-wall treatment. For breast or chest wall without regional nodes, offer 26 Gy in five fractions over one week; consider 40 Gy in 15 fractions over three weeks for a radiosensitivity diagnosis, implant reconstruction or another factor making that schedule more acceptable, such as high BMI or fibromyalgia.
- 4Coordinate systemic therapy and reconstruction review so wound or implant complications are addressed without losing the radiotherapy window.
- 5After neoadjuvant chemotherapy, offer postmastectomy radiotherapy when pretreatment investigations showed macrometastatic node positivity, or when postoperative histology shows macrometastatic nodes or involved margins. Consider it for node-negative T3 disease identified before or after treatment. A favourable response therefore does not erase an indication established by the original regional burden.
- 6Select nodal areas deliberately. After primary surgery, do not irradiate regional nodes for histologically node-negative disease and do not add axillary radiotherapy after axillary clearance. Offer supraclavicular irradiation for at least four involved axillary nodes, or for one to three positive nodes with other poor prognostic factors and good performance status. Consider internal mammary inclusion for macrometastatic node-positive disease; record the separate rationale for each target.
03Oncoplastic pathwayReconstruct the tumour bedA large volume-displacement conservation procedure has moved tissue and a boost decision depends on the original cavity.+
- 1Obtain the operative report, specimen orientation, preoperative images and clip map rather than using the skin scar as the target.
- 2Ask the surgeon and radiologist to resolve clip patterns that no longer outline one coherent bed.
- 3Choose whole- or partial-breast fields and any boost only after target confidence and recurrence risk are clear.
- 4Explain the uncertainty and expected cosmetic effects to the patient and record the multidisciplinary decision.
04Selected partial-breast or omission pathwayMatch every low-risk eligibility featureA woman with clear margins after conservation for invasive cancer asks whether she needs whole-breast treatment, partial-breast treatment or no radiotherapy.+
- 1AlternativeFirst verify the invasive type, tumour size, nodes, grade, ER and HER2 and the final radial margins. Whole-breast radiotherapy remains the NICE offer after conservation for invasive cancer. A favourable single feature, such as age or ER positivity, is insufficient to select an alternative.
- 2Consider external-beam partial-breast treatment when all NICE low-risk features fit: age at least 50, tumour no larger than 3 cm, N0, ER-positive, HER2-negative, grade 1 or 2, non-lobular invasive type and clear margins, with advice to take adjuvant endocrine therapy for at least five years. Discuss equivalent five-year local recurrence in the cited comparison, uncertainty beyond five years and possible reduction in late effects before a shared decision.
- 3Consider omission only in the separate very-low-risk population: age at least 65, T1N0, ER-positive, HER2-negative, grade 1 or 2, clear conservation margins and willingness to take endocrine therapy for at least five years. This is a consideration with informed choice, not a requirement to omit treatment in every older person.
- 4For that defined omission population, NICE describes about 50 local recurrences per 1,000 women over five years without radiotherapy versus about 10 per 1,000 with it, with the same overall survival at ten years. Explain that these are different outcomes and time horizons. Discuss breast soreness, cosmetic change and fibrosis as well as the cited lack of increased serious late effects in this low-risk comparison; do not generalise the figures to higher-risk disease.
- 5Document the chosen approach, endocrine commitment, practical attendance needs and the plan if treatment becomes intolerable. When radiotherapy is selected, discuss the current non-nodal fractionation options alongside its benefits and harms. Revisit target confidence after oncoplastic surgery before selecting a partial-breast field.
05Complications, monitoring and follow-upAdverse effects, response and longer-term review.
- During treatment, assess erythema, moist desquamation, breast or chest-wall oedema, pain, fatigue and any interruption requiring clinical review.
- After radiotherapy, provide skin care and a named contact for worsening pain, infection-like change, breathlessness or rapid swelling rather than routine antibiotics.
- At later review, assess fibrosis, breast size or shape, telangiectasia, shoulder range, lymphoedema and reconstruction contracture or failure.
- Continue annual mammography of remaining breast tissue and assess interval symptoms; routine mammography is not performed on mastectomy soft tissue.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
Five fractions has a boundary
The NICE 26 Gy offer is explicit for breast or chest-wall treatment without regional nodal irradiation; nodal fields need separate evidence and protocol.
The scar is not the bed
Oncoplastic incisions can be remote from the excision cavity, so clips and operative anatomy are necessary for accurate targeting.
Mastectomy can retain regional risk
Skin flaps, chest wall and lymphatic basins can harbour microscopic disease when nodes, margins or original extent are adverse.
Breath hold protects organs
For many left-sided plans, deep inspiration increases heart–chest-wall separation and can reduce cardiac dose when the patient can reproduce it.
07Common pitfallsFrequent interpretation and management errors.
- 01
Automatically applying 26 Gy in five fractions to a plan that includes regional nodes extends the NICE recommendation beyond its stated population.
- 02
Assuming every mastectomy eliminates radiotherapy can undertreat a patient with involved margins, macroscopic nodes or locally advanced disease.
- 03
Contouring an oncoplastic tumour bed from the visible scar alone risks missing displaced tissue and irradiating the wrong volume.
- 04
Reassuring a patient that skin effects are the only toxicity omits lymphatic, reconstructive, cardiac, pulmonary and late cosmetic consequences.