Breast Cancer

🔎 Introduction

• Breast cancer is the most common malignancy in women globally and a leading cause of cancer death.
• Most cancers arise from the epithelium of ducts (invasive ductal carcinoma / NST) or lobules (invasive lobular carcinoma).
• Outcomes have improved because of screening, earlier presentation, and targeted systemic therapies guided by receptor status (ER/PR/HER2).
• Male breast cancer is uncommon but important: it tends to present later, so a new unilateral lump or nipple change in a man warrants urgent assessment.

📊 Epidemiology

• Global burden: ~2.3 million diagnoses/year and ~670,000 deaths (most recently reported for 2022).
• UK burden: ~55,000 women and ~400 men diagnosed each year (plus ~7,000 DCIS diagnoses/year).
• Age: Risk rises with age; most cases occur after 50.
• Equity point: Survival varies with deprivation and stage at diagnosis—early presentation and access to diagnostics matter.

⚠️ Risk Factors

Teaching pearl: Only a minority (~5–10%) are strongly hereditary; most are sporadic, so any new suspicious symptom still needs proper assessment.

🧾 Differential Diagnosis of a Breast Lump

🧬 Molecular / Receptor-Based Subtypes

💡 High-Yield Pearls

• IDC (NST) vs ILC: IDC often forms a discrete mass; ILC can be subtle (thickening, distortion) and more often multifocal/bilateral → MRI can help pre-op planning.
• Microcalcifications: Clustered pleomorphic microcalcifications on mammography can be the earliest sign of DCIS.
• Red flags: Skin tethering, peau d’orange, new nipple inversion, bloody unilateral discharge, fixed nodes, and any inflammatory picture not settling promptly.

🔬 Investigations

• Triple assessment is standard: clinical exam + imaging + tissue diagnosis.
• Imaging: Mammography (excellent for microcalcifications), ultrasound (young/dense breasts; cystic vs solid), MRI (high-risk screening; lobular cancer staging; problem-solving).
• Biopsy: Core biopsy is typical; cytology may be adjunctive for nodes/cysts.
• Histopathology: Type + grade (Nottingham), lymphovascular invasion, DCIS component; node status.
• Receptors: ER/PR/HER2 and proliferation (Ki-67) guide systemic therapy and prognosis.

📌 Staging

• TNM remains foundational; stage strongly predicts outcomes and drives treatment intensity.
• Baseline staging investigations are tailored: early disease often needs no extensive scanning; higher stage/biologically aggressive disease may need CT/Bone scan/PET-CT per MDT.

💊 Treatment (MDT-driven)

• Surgery: Wide local excision (lumpectomy) + radiotherapy OR mastectomy ± reconstruction.
• Axilla: Sentinel node biopsy; axillary clearance/selective radiotherapy depending on nodal disease and MDT approach.
• Radiotherapy: Standard after breast-conserving surgery; post-mastectomy in selected higher-risk cases.
• Systemic therapy: Endocrine therapy for ER+; chemo for higher-risk biology/stage (including many TNBC/HER2+); HER2-targeted therapy for HER2+ disease.
• Supportive care: Fertility counselling where relevant, bone health with aromatase inhibitors, cardiotoxicity monitoring with HER2 therapy/anthracyclines, and lymphoedema risk reduction strategies.

📈 Prognosis

• Stage at diagnosis is the biggest determinant: early-stage disease has excellent long-term survival.
• Worse prognosis: higher grade, node-positive disease, adverse biology (e.g., TNBC), and delayed presentation.
• Modern targeted therapy (especially in HER2+ disease) has significantly improved outcomes compared with historical cohorts.

🩻 Screening (UK)

• NHS breast screening typically invites people registered as female from age 50 up to their 71st birthday, every 3 years.
• Higher-risk pathways (e.g., strong family history / BRCA carriers) may involve annual MRI ± mammography from younger ages via specialist genetics/familial breast clinics.

🌟 Survivorship

• Follow-up is individualised and MDT-led: focus on recurrence symptoms, treatment complications, psychosocial needs, and health promotion.
• Common long-term issues: lymphoedema, menopausal symptoms, bone loss (AI), cardiotoxicity risk, fatigue, anxiety, and return-to-work challenges.
• Encourage patients to report: new lump, persistent bone pain, breathlessness, neurological symptoms, or unexplained weight loss.

🧩 Three Mini-Cases (for ward/clinic teaching)

Case 1 — Screen-detected microcalcifications

• Presentation: 56F, asymptomatic, routine NHS screening mammogram shows clustered pleomorphic microcalcifications in upper outer quadrant.
• Most likely diagnosis: DCIS (or invasive cancer with DCIS component).
• Next best step: Triple assessment with image-guided biopsy (often stereotactic core biopsy for calcifications).
• Teaching point: Calcifications reflect disordered epithelial growth and necrosis within ducts; DCIS is “pre-invasive” but can progress, so management aims to prevent invasion while minimising overtreatment.

Case 2 — “Mastitis” that doesn’t settle

• Presentation: 48F, 3 weeks of breast erythema, warmth, swelling, peau d’orange appearance; partial response to antibiotics, still worsening.
• Key concern: Inflammatory breast cancer (dermal lymphatic invasion) until proven otherwise.
• Next best step: Urgent breast clinic referral for triple assessment; imaging + core biopsy (and consider skin punch biopsy if dermal involvement suspected).
• Teaching point: The pathophysiology is lymphatic obstruction causing oedema and skin changes—if “infection” doesn’t rapidly improve, assume malignancy and escalate early.

Case 3 — New unilateral lump in a man

• Presentation: 67M with a firm retroareolar lump and new nipple retraction; no pain; no clear gynaecomastia trigger.
• Most likely diagnosis: Male breast cancer (differential includes gynaecomastia, but nipple change is worrying).
• Next best step: Urgent “two-week wait” breast referral for triple assessment (clinical + ultrasound/mammography + core biopsy).
• Teaching point: Men have less breast tissue, so tumours reach skin/nipple earlier; unilateral hard mass, skin/nipple changes, or bloody discharge should never be dismissed as benign.

Case 4 — Axillary lump with “normal breast” on exam

• Presentation: 52F notices a painless right axillary lump. Breast self-exam feels “normal”; no skin/nipple change. No fevers or recent infection.
• Key concern: Occult breast cancer presenting with nodal disease (or less commonly lymphoma/metastatic melanoma).
• Next best step: Urgent breast clinic referral for triple assessment: targeted axillary ultrasound + needle sampling (FNA/core) of the node, plus mammography ± breast ultrasound; consider breast MRI if initial imaging is unrevealing but node pathology suggests breast primary.
• Teaching point: The lymphatics drain breast tissue to axillary nodes, so metastatic spread can declare itself in the axilla before a palpable breast mass exists; pathology of the node (e.g., ER/HER2 staining) can “point back” to the breast and guide treatment.

Case 5 — New lump during pregnancy / breastfeeding

• Presentation: 34F, 20 weeks pregnant (or 3 months postpartum), new firm breast lump that persists >2 weeks. Mild tenderness but no systemic sepsis; thinks it’s “blocked duct”.
• Key concern: Pregnancy-associated breast cancer (diagnosis is often delayed because physiological breast changes mask pathology).
• Next best step: Urgent referral for triple assessment adapted to pregnancy: ultrasound first-line; core biopsy is safe; mammography can be done with abdominal shielding if indicated; involve MDT early (breast + obstetrics).
• Teaching point: In pregnancy/lactation the breast is more dense and nodular, so “benign-sounding” explanations are common—your safety net is duration and persistence: a lump that doesn’t resolve quickly needs imaging and tissue, because delay worsens stage at diagnosis.

📚 References

• WHO breast cancer fact sheet (global burden, 2022 figures).
• NHS: Who breast screening is for (age range and invitation policy).
• NICE NG101: Early and locally advanced breast cancer (diagnosis/management framework, UK context).