Locally advanced and metastatic breast cancer

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Locally advanced breast cancer includes extensive breast, skin, chest-wall or regional nodal disease without distant metastasis. It carries high systemic risk but may be cured through neoadjuvant systemic treatment, surgery and radiotherapy. Inflammatory cancer is a particularly urgent presentation and breast-conserving surgery is generally not appropriate after response; modified radical mastectomy and comprehensive radiation usually form the local pathway. Progression during neoadjuvant treatment requires immediate reassessment rather than completing an ineffective course.

Metastatic treatment begins by confirming extent and biology. An accessible metastasis is sampled to prove recurrence and reassess ER and HER2, while molecular tests answer defined therapeutic questions. Symptoms, performance, comorbidity, organ function, prior treatment and pace matter as much as scan volume. Visceral crisis is reserved for severe organ compromise requiring the highest probability of rapid response; it must not be used as shorthand for any visceral lesion to bypass endocrine therapy.

Systemic sequences are subtype specific. ER-positive, HER2-negative disease without crisis usually starts with endocrine therapy and CDK4/6 inhibition, then uses endocrine and molecularly targeted options according to acquired resistance before chemotherapy becomes necessary. HER2-positive disease uses HER2 combinations and antibody–drug conjugates in a funded sequence. Triple-negative disease may use immunotherapy when the validated PD-L1 indication is met or a PARP inhibitor for eligible germline BRCA-associated disease, alongside chemotherapy and trials.

Support is active treatment. Bone agents reduce fracture and other skeletal events; radiotherapy relieves bone, brain, plexus and chest-wall symptoms; surgery stabilises selected fractures or decompresses neural structures; drainage controls effusions; specialist dressings, topical haemostasis and antibiotics manage fungation. Palliative care improves symptom control and decisions from diagnosis, while advance care planning runs alongside rather than replacing anticancer treatment.

Key points

Locally advanced M0 breast cancer remains potentially curable and usually receives systemic treatment first, followed by operability review, surgery and radiotherapy; stage IV disease is generally treated for durable control and quality of life.
Inflammatory breast cancer is a clinical pattern of rapid erythema and oedema from dermal lymphatic involvement and needs prompt core and often skin biopsy, systemic staging and multimodality treatment.
At metastatic diagnosis, biopsy an accessible lesion when feasible and repeat ER and HER2 because treatment targets can differ from the original primary.
First-line staging commonly uses contrast CT chest, abdomen and pelvis with bone assessment or an appropriate whole-body modality; use brain MRI for neurological symptoms or subtype- and stage-directed indications.
For ER-positive, HER2-negative metastatic disease without visceral crisis, endocrine therapy combined with a CDK4/6 inhibitor is generally preferred to upfront chemotherapy.
Visceral metastasis is not synonymous with visceral crisis. Stable liver deposits with preserved function can still receive endocrine-based treatment when biology and tempo support it.
HER2-positive disease receives sequential HER2-directed combinations; monitor cardiac function and recognise interstitial lung disease early with antibody–drug conjugates.
Triple-negative treatment depends on PD-L1, germline BRCA and other current biomarkers, treatment-free interval, organ function and prior perioperative exposure.
Bone-modifying therapy, dental prevention, calcium and vitamin D review, analgesia and stabilising or palliative radiotherapy reduce skeletal morbidity but do not replace systemic cancer control.
Use local radiotherapy, surgery, ablation, drainage, stenting or wound care to relieve specific symptoms or prevent catastrophe while systemic treatment addresses disease elsewhere.
Assess response by symptoms, examination, organ function and imaging at intervals appropriate to treatment; tumour markers may support a trend but should not alone trigger a regimen change.
Discuss treatment goals, likely absolute benefit, toxicity, fertility and menopause, work, caregiving, future lines and preferred place of care before crisis removes choice.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Progression after early disease

Micrometastatic clones can remain dormant or evolve after curative treatment, with relapse timing shaped by subtype, burden, treatment sensitivity and adherence.

De novo stage IV presentation

Some patients first present with distant disease, sometimes after a breast, nodal, bone, neurological, respiratory or liver symptom rather than a recognised primary mass.

Locally advanced primary biology

Large, fixed, skin- or chest-wall-involving and inflammatory cancers may remain M0 but have high systemic risk and require multimodality downstaging.

Acquired treatment resistance

ESR1, PI3K–AKT, HER2 and cell-cycle pathway changes, drug efflux and clonal selection permit progression despite initially effective endocrine or targeted therapy.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Tumour cells complete the metastatic cascade
Invasion, intravasation, circulation survival, extravasation and niche adaptation allow breast-cancer clones to colonise bone, liver, lung, brain and distant nodes.
2
Subtypes show organ preference
ER-positive disease commonly involves bone, HER2-positive and triple-negative disease more often reaches viscera and brain, although any subtype can spread anywhere.
3
Bone lesions remodel the microenvironment
Tumour stimulates osteoclast and osteoblast signalling, releasing growth factors that sustain cancer and cause pain, fracture, hypercalcaemia and cord compression.
4
Receptor phenotype can evolve
Therapy and clonal selection can change ER or HER2 expression between primary and metastasis, so accessible recurrent disease should be re-biopsied when clinically useful.
5
Organ dysfunction defines crisis
Visceral crisis means severe organ compromise and rapid deterioration, not simply the presence of liver or lung metastases, and it favours treatment with a prompt response.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Locally advanced breast disease

Large fixed tumour, skin ulceration, chest-wall fixation, extensive nodes or inflammatory change without distant spread requires a curative-intent multimodality assessment.

Bone-predominant metastasis

Persistent focal night pain, fracture, hypercalcaemia or vertebral symptoms are common in ER-positive disease and need structural and neurological assessment.

Visceral progression

Breathlessness, pleural fluid, jaundice, hepatomegaly, ascites, abdominal pain or rapid biochemical decline may indicate lung, pleural or liver disease.

Brain or leptomeningeal diseaseRed flag

Headache, seizure, focal deficit, personality change, cranial neuropathy or radicular symptoms requires urgent contrast MRI and specialist review.

Chest-wall fungation

Ulceration, exudate, malodour, infection, bleeding and mixed neuropathic pain require wound, radiation and systemic assessment, not dressings alone.

Visceral crisisRed flag

Rapid clinical deterioration with severe liver, lung, marrow or other organ dysfunction calls for an urgent high-response treatment plan and parallel supportive rescue.

Red flags requiring action

New severe back pain, limb weakness, sensory change, gait disturbance or bladder or bowel dysfunction suggests metastatic spinal cord compression.
Seizure, progressive headache, focal deficit, vomiting or reduced consciousness raises brain metastasis, haemorrhage or raised intracranial pressure.
Rapid bilirubin rise, respiratory failure from lymphangitic disease or marrow failure from tumour can constitute visceral crisis requiring a fast-response plan.
Thirst, confusion, constipation, polyuria or dehydration suggests malignant hypercalcaemia and needs urgent corrected or ionised calcium assessment.
Fever during systemic treatment, new dyspnoea or unilateral leg swelling requires immediate assessment for neutropenic sepsis, drug pneumonitis or venous thromboembolism.
Brisk bleeding, malodour, spreading cellulitis or severe pain from a fungating breast or chest-wall mass needs urgent haemostasis, infection and wound support.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

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
Preferred biopsy of accessible recurrenceFirst stepPreferred
Why
Confirm metastatic breast cancer, exclude a second primary and reassess predictive receptors.
Interpretation and limitations
Repeat ER and HER2 with validated methods and compare with the original; if bone is sampled, coordinate decalcification because harsh processing can impair receptor and molecular assays.
02
First-line contrast CT chest abdomen and pelvisFirst line
Why
Map visceral, nodal, chest-wall and osseous disease and create a measurable response baseline.
Interpretation and limitations
Combine with dedicated bone imaging or an appropriate whole-body modality; investigate indeterminate lesions before a high-consequence treatment change when feasible.
03
MRI for neural or local questions
Why
Define brain, leptomeningeal, spinal-cord, brachial-plexus or locally invasive breast and chest-wall disease.
Interpretation and limitations
Use urgent whole-spine MRI for suspected cord compression and contrast brain MRI for neurological features; a negative CT head does not exclude small metastases.
04
Biomarker and genomic testing
Why
Identify current endocrine, HER2, immune and inherited or acquired molecular treatment targets.
Interpretation and limitations
Test only markers linked to an available treatment or trial, such as PD-L1, germline BRCA, PIK3CA or ESR1 in the appropriate subtype and line; interpret tissue and plasma limitations.
05
Organ function and complication panel
Why
Assess urgency, treatment fitness and reversible complications before selecting systemic therapy.
Interpretation and limitations
Include FBC, renal and liver profile, calcium, albumin and disease-specific tests; a rapid bilirubin, oxygen or marrow trajectory may define crisis more clearly than tumour diameter.
06
Baseline cardiac and bone assessment
Why
Quantify safety for HER2-directed, anthracycline, endocrine and bone-modifying treatment.
Interpretation and limitations
Use echocardiography or equivalent for cardiotoxic therapy and dental, renal, calcium and vitamin D assessment before bisphosphonate or denosumab.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Second primary malignancy

Lung, ovarian, gastrointestinal, haematological and other cancers can occur after breast cancer; biopsy prevents assuming every new lesion is recurrent breast disease.

Treatment toxicity

Radiation change, cardiomyopathy, drug pneumonitis, endocrine musculoskeletal pain and infection can mimic pulmonary, bone, brain or constitutional progression.

Benign skeletal and neurological disease

Degenerative spine disease, osteoporotic fracture, neuropathy and migraine are common, but red flags or persistent focal symptoms warrant urgent cancer-directed imaging.

Inflammatory or thrombotic disease

Pneumonia, pulmonary embolism, sarcoid-like reaction and liver inflammation can resemble metastatic imaging and may coexist with active cancer.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Locally advanced M0Downstage within a curative sequenceFirst stepBreast, skin, chest-wall or regional nodal extent is advanced but distant staging remains negative.

1Confirm histology and ER and HER2, clip tumour and positive nodes, complete systemic staging and assess inflammatory features, operability and baseline cardiac and functional status.
2EscalationGive subtype-appropriate neoadjuvant systemic treatment and assess clinical response during therapy, escalating immediately for progression or threatened ulceration and bleeding.
3Re-discuss at the MDT for mastectomy or selected conservation and axillary surgery, then deliver indicated radiotherapy and response-adapted postoperative systemic treatment.

02Metastatic diagnosisReconfirm biology before sequencingImaging or symptoms suggest distant breast-cancer recurrence or de novo stage IV disease.

1Stabilise emergencies, obtain complete anatomical staging and biopsy a safe accessible lesion to establish current histology, ER and HER2 and exclude another primary.
2Assess performance, organ function, tempo, prior treatment, treatment-free interval, germline and acquired biomarkers and whether true visceral crisis is present.
3Agree the first systemic line, local symptom interventions, response interval and stopping criteria with the patient and multidisciplinary team, integrating palliative care at the outset.

03ER-positive HER2-negativePreserve endocrine sensitivity when safeMetastatic disease remains hormone-receptor positive and there is no organ-threatening visceral crisis.

1Choose an aromatase inhibitor or fulvestrant backbone with a CDK4/6 inhibitor according to menopausal status, previous adjuvant exposure, disease-free interval, comorbidity and interactions.
2At progression, re-evaluate adherence, tempo and targetable resistance such as PIK3CA or ESR1 and use a funded endocrine-targeted option while clinical benefit persists.
3Move to chemotherapy when endocrine resistance, symptomatic rapid progression or organ dysfunction makes a faster non-endocrine strategy necessary, revisiting goals before each line.

04HER2 or triple-negativeSequence targeted and cytotoxic treatmentRe-biopsy confirms HER2-positive or triple-negative metastatic biology.

1For HER2-positive disease, choose the current funded HER2-directed combination from prior exposure and timing and monitor cardiac and pulmonary toxicity carefully.
2For triple-negative disease, review PD-L1, germline BRCA and prior neoadjuvant agents before selecting immunotherapy, PARP inhibition, antibody–drug conjugate or chemotherapy within its exact indication.
3Re-image after an appropriate number of cycles, distinguish drug toxicity from progression and retain effective systemic treatment while using focused local treatment for selected symptomatic or oligoprogressive sites.

05Bone and brainPrevent irreversible metastatic morbiditySkeletal, spinal or central-nervous-system metastasis is identified.

1For cord or brain-pressure symptoms, start the emergency steroid and imaging pathway and obtain same-day spinal, neurosurgical or radiation oncology input.
2Assess fracture and instability risk, use analgesia and palliative radiotherapy and involve orthopaedics before weight bearing through an impending long-bone fracture.
3Start a bone-modifying agent when appropriate after dental and biochemical review and coordinate stereotactic, surgical or whole-brain treatment with CNS-active systemic options.

Key medicines and prescribing safety4 treatments · regimens, roles and cautions

Inhibits CDK4 and CDK6 and is a preferred first-line component for many ER-positive, HER2-negative metastatic cancers without visceral crisis.

Ribociclib with endocrine therapy

Give ribociclib 600 mg orally once daily on days 1 to 21 of each 28-day cycle with the selected endocrine partner; reduce to 400 mg and then 200 mg for protocol-defined toxicity.

Obtain FBC, liver tests, ECG and electrolytes at baseline and protocol intervals; manage neutropenia, hepatotoxicity and QT prolongation and review CYP3A interactions, pregnancy and menopausal suppression.

Delivers a topoisomerase-I payload through HER2 targeting and provides substantial control in eligible HER2-positive and selected HER2-low metastatic disease.

Trastuzumab deruxtecan

Give trastuzumab deruxtecan 5.4 mg/kg by intravenous infusion every 3 weeks within the licensed and current NICE-funded breast-cancer indication, with dose interruption and reduction according to toxicity.

New cough, dyspnoea, fever or infiltrates requires immediate interruption and urgent interstitial-lung-disease assessment; also monitor nausea, marrow, left-ventricular function and pregnancy risk.

Reduces pathological fracture, cord compression and need for skeletal radiation or surgery in breast cancer with bone metastases.

Zoledronic acid for bone metastases

Give zoledronic acid 4 mg intravenously every 3 to 4 weeks, extending the interval in selected stable patients and adjusting or withholding for renal impairment according to the product protocol.

Check dental health, creatinine, calcium, phosphate and vitamin D and counsel about hypocalcaemia, renal injury, acute-phase reaction and osteonecrosis of the jaw; do not combine casually with another bone-modifying agent.

Reduces tumour-associated oedema around the spinal cord and can preserve neurological function while radiotherapy or surgery is organised.

Dexamethasone for neurological compression

For suspected metastatic spinal cord compression with neurological signs, give dexamethasone 16 mg orally or intravenously as soon as possible and continue 16 mg daily while urgent imaging and definitive treatment are arranged, then taper to the specialist plan.

Do not delay MRI or definitive decompression. Monitor glucose, infection, mental state, gastrointestinal risk and proximal weakness and stop if imaging excludes compression unless another indication remains.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Skeletal-related events

Bone metastases cause pain, pathological fracture, spinal instability, cord compression and hypercalcaemia, leading to immobility and loss of independence.

Central nervous system disease

Brain or leptomeningeal metastases cause seizures, focal deficits, cranial neuropathies, raised pressure and cognitive or behavioural change.

Visceral and marrow failure

Liver replacement, lymphangitic lung spread, pleural disease or marrow infiltration can cause jaundice, respiratory failure, cytopenias and bleeding.

Local chest-wall morbidity

Ulceration, fungation, malodour, exudate, infection, lymphoedema, brachial-plexus pain and bleeding can dominate quality of life profoundly.

Cumulative treatment toxicity

Cardiac dysfunction, pneumonitis, neuropathy, cytopenia, diarrhoea, endocrine symptoms and psychosocial burden increase as successive treatments and disease overlap.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

At each visit, record pain, function, weight, performance, patient priorities and organ-specific symptoms alongside laboratory and imaging response.
For endocrine and CDK4/6 treatment, monitor adherence, FBC, liver tests, ECG or interactions as agent specific and review menopause, bone, diarrhoea and thrombotic effects.
For HER2-directed treatment, monitor left-ventricular function and investigate cough or breathlessness urgently for pneumonitis, infection, embolism, effusion and progression.
For bone agents, review dental symptoms, renal function, calcium, vitamin D, fracture risk and new thigh or jaw pain before ongoing doses.
Use reproducible imaging at clinically meaningful intervals and compare with baseline, but change treatment only after integrating symptoms, organ function and potential immune, radiation or healing effects.
Track fungating-wound bleeding, odour, exudate, infection, pain and dressing burden and involve tissue-viability, radiation and palliative teams early.
Revisit resuscitation, emergency contacts, future treatment thresholds, home support and preferred place of care before performance deterioration limits discussion.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Visceral disease is not visceral crisis

Liver or lung metastases with stable organ function can receive endocrine-based treatment; crisis requires severe dysfunction and rapid deterioration.

Biopsy can redirect years of treatment

A metastasis may lose or gain receptor expression or prove to be another primary, changing every subsequent systemic choice.

Bone scans show reaction as well as tumour

Early healing can increase sclerosis or tracer uptake, so apparent flare must be interpreted with symptoms, timing and other sites.

Local therapy and systemic therapy cooperate

Radiation or surgery can control one painful or dangerous site while an otherwise effective systemic regimen continues elsewhere.

Inflammatory cancer is clinically defined

Dermal lymphatic invasion supports diagnosis but its absence in a small skin sample does not exclude the characteristic rapid diffuse clinical presentation.

Palliative care does not mean stopping oncology

Early symptom, family and decision support can accompany multiple active anticancer lines and often protects treatment tolerance and patient choice.

11Common pitfallsFrequent interpretation and management errors.

01
Calling locally advanced M0 disease incurable and omitting a coordinated curative sequence.
02
Assuming a distant lesion is breast recurrence without biopsy when another diagnosis is plausible.
03
Using the primary tumour receptor result forever despite accessible recurrent tissue and potential phenotype change.
04
Calling any liver or lung metastasis visceral crisis and bypassing effective endocrine-based treatment.
05
Starting a bone-modifying drug without dental, renal, calcium and vitamin D review.
06
Continuing trastuzumab deruxtecan through new respiratory symptoms without urgent interstitial-lung-disease assessment.
07
Using tumour-marker rise alone to declare progression or change therapy.
08
Waiting for complete neurological deficit before activating the cord-compression pathway.
09
Deferring palliative, wound and advance-care support until all anticancer treatment has ended.