Breast cancer · House

Red Flags

New breast lump, skin tethering, peau d'orange, nipple retraction or discharge, axillary lymphadenopathy — same-day imaging and triple assessment^[1]
Inflammatory breast cancer (rapid skin changes, oedema, erythema, peau d'orange) — emergent multidisciplinary oncology; neoadjuvant chemotherapy^[1]
BRCA1/2 or other high-penetrance mutation in patient or strong family history — clinical genetics; consider risk-reducing surgery and intensified surveillance^[1]
Pregnancy with newly diagnosed breast cancer — multidisciplinary oncology + obstetric; staging-appropriate chemotherapy from second trimester possible^[1]

First-line treatment

Interventions

Multidisciplinary tumour board for all^[1]
Surgical, medical, and radiation oncology + radiology + pathology; treatment driven by stage and molecular subtype (luminal A/B, HER2-positive, triple-negative)
Surgery — BCS or mastectomy^[1]
Breast-conserving surgery with whole-breast radiotherapy is equivalent to mastectomy for early-stage in survival; mastectomy for large tumour:breast ratio, multicentric disease, or contraindication to RT; sentinel lymph node biopsy for clinically node-negative
Adjuvant radiotherapy^[1]
Whole-breast RT after BCS; post-mastectomy RT for ≥4 positive nodes, T3+, or close margins; nodal RT per axillary status
Genomic risk-stratification (Oncotype DX, MammaPrint)^[1]
ER-positive HER2-negative N0 disease — informs decision on adjuvant chemotherapy where benefit uncertain; access varies by setting

First-line drug therapy

Drug	Class	Adult	Paediatric	Notes
Tamoxifen^[1]	Selective estrogen receptor modulator	20 mg PO daily × 5–10 years	—	Adjuvant for premenopausal ER-positive; risk of VTE and endometrial cancer — counsel about postmenopausal bleeding; CYP2D6 interactions (avoid SSRIs that inhibit CYP2D6 like paroxetine, fluoxetine)
Aromatase inhibitor (anastrozole, letrozole, exemestane)^[1]	Aromatase inhibitor	Anastrozole 1 mg PO daily; letrozole 2.5 mg PO daily; exemestane 25 mg PO daily — × 5–10 years	—	Adjuvant for postmenopausal ER-positive; switch from tamoxifen at menopause; bone loss — DXA and calcium/vitamin D ± bisphosphonate; arthralgia
Trastuzumab^[1]	Anti-HER2 monoclonal antibody	Loading 8 mg/kg IV then 6 mg/kg every 3 weeks × 1 year; or weekly schedule	—	All HER2-positive (IHC 3+ or FISH amplified); cardiotoxicity — baseline and serial echocardiogram; combine with chemotherapy then continue alone
Pertuzumab + trastuzumab + chemotherapy^[1]	Dual HER2 blockade	Pertuzumab 840 mg loading then 420 mg IV every 3 weeks	—	Neoadjuvant or adjuvant in HER2-positive; combine with trastuzumab and taxane; cardiac monitoring
CDK4/6 inhibitor (palbociclib, ribociclib, abemaciclib)^[1]	Cyclin-dependent kinase inhibitor	Palbociclib 125 mg PO daily 21/28; ribociclib 600 mg PO daily 21/28; abemaciclib 150 mg PO BD continuous	—	Combined with endocrine therapy in advanced ER-positive HER2-negative disease and selected high-risk early-stage; neutropenia, diarrhoea (abemaciclib), QTc (ribociclib)
Neoadjuvant/adjuvant taxane + anthracycline chemotherapy^[1]	Combination chemotherapy	AC-T or TC regimens per local protocol; dose-dense or weekly paclitaxel options	—	Standard for triple-negative, high-risk ER-positive, HER2-positive (with trastuzumab); cardiotoxicity, neuropathy, alopecia, neutropenia
PARP inhibitor (olaparib, talazoparib)^[1]	Poly ADP-ribose polymerase inhibitor	Olaparib 300 mg PO BD; talazoparib 1 mg PO daily	—	BRCA-mutated metastatic and selected adjuvant high-risk early-stage; counselling for genetic testing; haematological monitoring

Tamoxifen^[1]

Selective estrogen receptor modulator

Adult: 20 mg PO daily × 5–10 years
Paediatric: —

Adjuvant for premenopausal ER-positive; risk of VTE and endometrial cancer — counsel about postmenopausal bleeding; CYP2D6 interactions (avoid SSRIs that inhibit CYP2D6 like paroxetine, fluoxetine)

Aromatase inhibitor (anastrozole, letrozole, exemestane)^[1]

Aromatase inhibitor

Adult: Anastrozole 1 mg PO daily; letrozole 2.5 mg PO daily; exemestane 25 mg PO daily — × 5–10 years
Paediatric: —

Adjuvant for postmenopausal ER-positive; switch from tamoxifen at menopause; bone loss — DXA and calcium/vitamin D ± bisphosphonate; arthralgia

Trastuzumab^[1]

Anti-HER2 monoclonal antibody

Adult: Loading 8 mg/kg IV then 6 mg/kg every 3 weeks × 1 year; or weekly schedule
Paediatric: —

All HER2-positive (IHC 3+ or FISH amplified); cardiotoxicity — baseline and serial echocardiogram; combine with chemotherapy then continue alone

Pertuzumab + trastuzumab + chemotherapy^[1]

Dual HER2 blockade

Adult: Pertuzumab 840 mg loading then 420 mg IV every 3 weeks
Paediatric: —

Neoadjuvant or adjuvant in HER2-positive; combine with trastuzumab and taxane; cardiac monitoring

CDK4/6 inhibitor (palbociclib, ribociclib, abemaciclib)^[1]

Cyclin-dependent kinase inhibitor

Adult: Palbociclib 125 mg PO daily 21/28; ribociclib 600 mg PO daily 21/28; abemaciclib 150 mg PO BD continuous
Paediatric: —

Combined with endocrine therapy in advanced ER-positive HER2-negative disease and selected high-risk early-stage; neutropenia, diarrhoea (abemaciclib), QTc (ribociclib)

Neoadjuvant/adjuvant taxane + anthracycline chemotherapy^[1]

Combination chemotherapy

Adult: AC-T or TC regimens per local protocol; dose-dense or weekly paclitaxel options
Paediatric: —

Standard for triple-negative, high-risk ER-positive, HER2-positive (with trastuzumab); cardiotoxicity, neuropathy, alopecia, neutropenia

PARP inhibitor (olaparib, talazoparib)^[1]

Poly ADP-ribose polymerase inhibitor

Adult: Olaparib 300 mg PO BD; talazoparib 1 mg PO daily
Paediatric: —

BRCA-mutated metastatic and selected adjuvant high-risk early-stage; counselling for genetic testing; haematological monitoring

Safety-net

Be breast-aware: know what is normal for you and report any new lump, nipple change, skin change, or unexplained pain^[1]
Attend recommended mammography appointments — most early breast cancers are detected on screening before symptoms appear^[1]
Adjuvant therapy can last 5–10 years — adherence is the single biggest determinant of long-term survival; speak to your oncology team about side effects rather than stopping^[1]

Referral criteria

Suspicious clinical lesion, abnormal mammogram, or biopsy-proven cancerBreast cancer multidisciplinary clinic^[1]
Inflammatory breast cancer or rapidly progressive diseaseTertiary breast oncology same-week^[1]
BRCA1/2 mutation or strong family historyClinical genetics; consider risk-reducing mastectomy and salpingo-oophorectomy^[1]
Pregnancy with newly diagnosed breast cancerJoint oncology and obstetric clinic; staging-appropriate management^[1]

Clinical summary

Risk-stratified screening, triple-assessment diagnosis, and stage- and subtype-driven treatment of breast cancer in adult women.

References

1.ICMR Consensus Document for Management of Carcinoma of the Breast (2022); NCCN Breast Cancer Guidelines; St Gallen Consensus (2022)