Breast Cancer

Related Subjects: | Assessment of the Causes of Breast Tenderness/Pain (Mastalgia) | BRCA Genes (Familial Breast Cancer) | Breast Anatomy and Examination (OSCE) | Breast Cancer | Benign Breast Disease | Malignant Breast Disease | Breast Lumps: Clinical Approach | Mastitis and Breast Abscess | Malignant Breast Disease

🩺 Big picture: Most breast presentations in primary care are benign - but the job is to spot cancer early, refer appropriately, and ensure every patient gets triple assessment when indicated. 🔑 Think in 3 buckets: anatomy (what could this be?), risk (who is higher risk?), and pathway (who needs urgent breast clinic?).

🧬 Breast Anatomy (high-yield)

• Definition: The breast is a modified sweat gland covered by skin and subcutaneous tissue, made up of mammary glands + connective tissue.
• Duct–lobule system: Secretory lobules drain into ducts, which converge at the nipple.
• Lymphatic drainage (exam favourite):
  • 🟦 Axillary nodes: ~75%
  • 🟩 Parasternal/internal mammary nodes: ~20%
  • 🟪 Posterior intercostal nodes: ~5%

Why lymph matters: It explains why breast cancer can present with an axillary lump, why staging depends heavily on nodes, and why “breast-normal” exam does not exclude malignancy.

🧬 Genetic Risk Factors (BRCA-focused)

BRCA1 and BRCA2 are key genes that significantly increase the risk of breast and ovarian cancers and account for ~5% of all breast cancers.

• 🛡️ Tumour suppressor genes: loss of function removes “DNA repair / cell-cycle brakes”.
• 🧬 Autosomal-dominant inheritance (clinically: a strong family history pattern).
• 🧪 Genetic testing is available via specialist pathways.
• ⏳ Often younger presentations and/or multiple affected relatives.

🧠 Exam pearl: Only a minority of cancers are strongly hereditary, but a high-risk pedigree changes screening and referral thresholds - never ignore it.

🧪 When to consider genetic testing (red-flag family history)

Genetic testing should be carried out if there is:

• 👩‍👧 First-degree female relative with breast cancer at <40 years
• 👨 First-degree male relative with breast cancer
• 👩‍👩 First-degree relative with bilateral breast cancer
• 👨‍👩‍👧‍👦 Multiple first- or second-degree relatives with breast cancer

🏥 Breast Care Pathways - General Practice (UK)

📌 Safety-first principle: If you find an unexplained lump (breast or axilla), or skin/nipple changes suspicious of cancer, refer to a one-stop breast clinic for triple assessment.

🚦 Referral guide (use in OSCEs and on call)

• 🚨 Urgent suspected cancer pathway (aim: seen within 2 weeks) if:
  • 👩‍🦰 Age ≥30 with an unexplained breast lump (with or without pain)
  • 🫧 Age ≥30 with an unexplained axillary lump
  • 🍊 Skin changes suggestive of cancer (e.g., peau d’orange, tethering, ulceration)
  • 👁️ Age ≥50 with unilateral nipple symptoms: discharge, retraction, or other worrying unilateral change
• 🟡 Non-urgent referral to breast clinic if:
  • 👩 Age <30 with an unexplained breast lump (with or without pain)

Teaching pearl: Age cut-offs are guidelines, not permission to dismiss. If something is clearly suspicious clinically, escalate.

📝 What every referral should include (GP checklist)

• Symptoms: lump, nipple retraction, nipple discharge, skin changes, mastalgia, change in size/shape of breast
• Systemic features: weight loss, fatigue, shortness of breath, back pain, jaundice
• Risk factors: oestrogen exposure, personal history, screening history, family history, radiation, breastfeeding, smoking, alcohol, BRCA1/2
• Oestrogen exposure examples: COCP, early menarche, late menopause, nulliparity, obesity, PCOS, HRT

🏥 Breast Care in Hospital

📬 Screening programme (UK)

• 📅 People registered as female are typically invited for NHS breast screening between 50 and 53, then every 3 years until their 71st birthday (local variation exists across UK nations; higher-risk pathways differ).
• 🔍 Abnormal screening findings → referral to a one-stop breast clinic.

🏃 One-stop breast clinic & triple assessment

All patients requiring further investigation after screening or GP review are assessed in a one-stop breast clinic (see Fig 2.2). A triple assessment guides diagnosis and management:

• 🩺 Clinical history + examination
• 🖼️ Imaging (ultrasound and/or mammography)
• 🧫 Tissue diagnosis (core biopsy or cytology)

FIG 2.2 One-stop Breast Clinic. MDT, Multidisciplinary team; USS, ultrasound scan. Illustrated by Dr Hannah Punter.

🧠 Why triple assessment matters: Breast malignancy is a clinic + imaging + pathology diagnosis. A reassuring exam does not “rule out” cancer, and imaging alone cannot finalise management without tissue in most suspicious cases.

🧮 Triple assessment scoring (P / M or U / B or C)

Following triple assessment, a score is given based on:

• 🩺 Examination: P
• 🖼️ Imaging: U (ultrasound) or M (mammogram)
• 🧫 Pathology: B (histology core biopsy) or C (cytology)

Example: A P4, M4, B5 score means the mass looked suspicious/likely malignant clinically and on mammography, with histology confirming malignancy.

🧠 OSCE-ready “don’t miss” list (memorise)

• 🍊 Peau d’orange / significant skin tethering or dimpling
• 🩸 Unilateral bloody nipple discharge
• ↩️ New nipple inversion/retraction (especially unilateral)
• 🫧 Unexplained axillary lump
• 👨 Male breast lump or nipple change (often presents late)
• 🔥 “Mastitis” that does not settle promptly → consider inflammatory cancer (escalate)

📚 References (UK MLA)

• NICE NG12: Suspected cancer - recognition and referral (breast section; age thresholds and referral routes).
• NHS: Who breast screening is for (invitation ages and intervals).