01Purpose and principlesWhat the treatment does and how it fits into care.
The breast operation achieves local control while preserving the person’s priorities where oncologically safe. Conservation succeeds when all disease can be removed with acceptable margins and a reasonable cosmetic result, followed by indicated radiotherapy. Mastectomy becomes proportionate when distribution rather than simple diameter prevents complete conservation, when prior treatment limits radiotherapy, or when the patient prefers it after balanced discussion. Contralateral prophylactic surgery answers a separate future-risk question.
Oncoplastic surgery broadens conservation by combining cancer excision with volume displacement or replacement. It also raises planning demands: radiological extent, biopsy clips and tumour bed location must remain clear for pathology and radiotherapy. Mastectomy planning includes skin- or nipple-sparing feasibility and immediate or delayed reconstruction. A reconstruction option should not be presented as guaranteed until oncological, vascular, body-habitus and adjuvant-treatment factors are assessed.
Key points
- Breast-conserving surgery removes the tumour with an adequate rim of tissue and preserves breast shape; it is normally paired with postoperative breast radiotherapy.
- Mastectomy removes nearly all breast tissue and is considered for extensive or multicentric disease, inability to obtain acceptable margins, contraindication to required radiotherapy, inflammatory disease or informed preference.
- A larger tumour is not an automatic mastectomy: breast size, distribution, neoadjuvant response and oncoplastic displacement or replacement can make conservation feasible.
- Mastectomy does not automatically improve survival over appropriate conservation plus radiotherapy for a conservation-eligible early cancer, and it does not remove systemic recurrence risk.
- Offer immediate reconstruction after mastectomy when appropriate, including when radiotherapy may be needed, while explaining how radiotherapy can affect reconstructive complications and choices.
- Surgical consent covers margins and re-excision, specimen orientation, scars, nipple sensation, asymmetry, seroma, infection, pain, shoulder function, lymphoedema risk and recovery.
02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.
A localised lesion with a favourable breast-to-tumour ratio and a realistic route to clear margins can often be excised with acceptable appearance.
Diffuse malignant calcification, widely separated disease or persistent margin involvement may require removal of substantially more tissue than the breast can tolerate.
Prior breast irradiation, inability to position safely or a major contraindication to required radiotherapy may change the balance toward mastectomy.
Some patients prioritise breast preservation; others prioritise avoiding future ipsilateral procedures. The decision follows accurate outcome and complication information.
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
Concordant imaging extent mapFirst step - Why
- Define all malignant foci and calcification before choosing conservation or mastectomy.
- Interpretation and limitations
- Use mammography and ultrasound, with selected MRI for a defined uncertainty. Biopsy management-changing separate lesions where feasible.
- 02
Core pathology and biomarkers - Why
- Confirm invasive or in-situ disease and identify biology that may make neoadjuvant downstaging useful.
- Interpretation and limitations
- Histology alone does not dictate the breast operation; combine type, distribution, receptor status and likely response.
- 03
Anaesthetic and functional assessment - Why
- Identify comorbidity, smoking, frailty, diabetes and mobility factors that alter wound and reconstructive risk.
- Interpretation and limitations
- Optimisation may change timing or reconstructive technique, but should not produce unexplained cancer-treatment delay.
- 04
Reconstructive consultation - Why
- Compare flat closure, implant and autologous options and immediate versus delayed timing.
- Interpretation and limitations
- Include donor-site effects, recovery, revision probability and anticipated radiotherapy rather than discussing appearance alone.
04Treatment approachPreparation, options, escalation and aftercare.
01Worked case: conservation choiceTest whether preservation is genuinely feasibleFirst stepA 46-year-old has a unifocal 22 mm cancer in a medium-sized breast and strongly prefers conservation.+
- 1In this illustrative case, triple assessment confirms one 22 mm invasive focus with concordant imaging and pathology. There is no additional suspicious focus or diffuse calcification, the breast-to-tumour ratio is suitable and pretreatment axillary ultrasound is normal. The team confirms that complete excision with an acceptable breast shape is feasible.
- 2The patient receives a comparison of conservation with expected radiotherapy, possible further margin surgery, and mastectomy with reconstruction choices. She is medically suitable for either approach and can attend radiotherapy. She chooses conservation after explaining that preserving the breast does not remove the need for adjuvant treatment or eliminate distant recurrence risk.
- 3The surgeon performs the agreed excision with sentinel-node staging and precisely orients the specimen. Pathology confirms the invasive target, clear radial margins and negative sentinel nodes; imaging and specimen findings account for the original lesion, so no further breast surgery is required in this example.
- 4At wound review there is no infection or collection, shoulder movement is recovering and the patient is satisfied with the initial shape. The multidisciplinary team confirms the local result and refers for the indicated breast radiotherapy while systemic treatment is assessed from the final biology and risk.
- 5The patient receives the pathology explanation, named wound and oncology contacts and the next appointments. She can describe why radiotherapy remains part of her conservation plan and which wound or arm symptoms need earlier assessment.
02Extensive disease pathwayPlan mastectomy and reconstruction togetherBiopsy-proven high-grade DCIS spans two distant quadrants and conservation would remove most of the breast.+
- 1Verify radiological extent and tissue diagnosis for management-changing areas and exclude invasive disease where possible.
- 2Discuss mastectomy, sentinel-node biopsy for DCIS at mastectomy, flat closure and immediate reconstruction options before surgery. Offer immediate reconstruction discussion even if postoperative radiotherapy may be needed; explain how radiotherapy can affect complications, cosmetic outcome, technique and timing, and compare delayed reconstruction as part of informed choice.
- 3Explain that unexpected invasion, margins and final pathology may affect systemic treatment and radiotherapy even after mastectomy.
- 4Optimise smoking, diabetes and anaesthetic risk and coordinate breast and plastic surgery without losing the treatment timeline.
03Patient requests mastectomy pathwayExplore the reason before consentA patient eligible for conservation requests bilateral mastectomy because she believes it guarantees survival.+
- 1Ask what outcome she expects and correct the belief that more extensive local surgery necessarily improves survival or removes systemic risk.
- 2Separate treatment of the affected breast from contralateral future-risk reduction and obtain genetics assessment only when clinically indicated.
- 3Review radiotherapy, complications, sensation, reconstruction and recovery for each option and offer breast-care and psychological support.
- 4Respect a capacitated informed preference after adequate time, while documenting the alternatives and the patient’s stated priorities.
05Complications, monitoring and follow-upAdverse effects, response and longer-term review.
- Before theatre, confirm the side, operation, lesion localisation, axillary plan, reconstruction plan, antibiotic and thrombosis assessment and any required clips.
- Postoperatively, monitor skin or flap perfusion, haematoma, infection, seroma, pain, drain output and shoulder movement, escalating threatened reconstruction promptly.
- At pathology review, verify invasive and in-situ extent, margins, receptor profile and nodes before deciding on re-excision, radiotherapy and systemic treatment.
- After recovery, assess breast or chest-wall symptoms, body image, prosthetic needs, arm morbidity and annual mammographic surveillance of remaining breast tissue.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
Distribution beats diameter
Two small widely separated cancers can be harder to conserve than one larger lesion that responds well and permits an oncoplastic excision.
Mastectomy may still need radiotherapy
Node burden, tumour size, margins and neoadjuvant context can indicate chest-wall or regional radiotherapy despite removal of the breast.
Oncoplastic planning is oncological
Reshaping can move the tumour bed, so clips, specimen orientation and multidisciplinary communication are essential for margins and radiotherapy.
Flat closure is an active option
Aesthetic flat closure should be discussed alongside reconstruction rather than framed as failure or absence of reconstructive care.
07Common pitfallsFrequent interpretation and management errors.
- 01
Presenting mastectomy as automatically safer or curative can push patients toward larger surgery without an accurate survival comparison.
- 02
Planning conservation from one lesion measurement while ignoring separate calcification or discordant examination risks incomplete excision.
- 03
Promising a nipple-sparing or immediate reconstruction before final oncological and vascular assessment can create avoidable distress.
- 04
Forgetting that conservation usually entails radiotherapy leaves the patient unable to compare the complete treatment pathways.