GC181 Breast Mass Breast Cancer; Benign Breast Diseases; Mammography; Breast Cancer Screening
A breast mass is a localized swelling in the breast that may represent benign conditions such as fibroadenoma, fibrocystic changes, or cysts, or malignant disease such as breast carcinoma, evaluated through clinical examination, mammography, and tissue sampling as part of a triple assessment approach.
Breast Mass, Breast Cancer, Benign Breast Diseases, Mammography & Breast Cancer Screening
This GC 181 lecture by Dr Michael Co is a cornerstone surgical lecture that covers the entire clinical journey of a patient presenting with a breast symptom — from screening and prevention, through clinical assessment, imaging, biopsy, pathological classification, all the way to definitive surgical, adjuvant, and palliative management. It is consistently tested in the Fourth Summative exam via MCQs, SAQs, and minicases.
Big Idea: A breast lump is common. Your job is to systematically distinguish benign from malignant disease using the Triple Assessment (clinical + radiological + pathological), then stage and treat appropriately. Screening aims to catch cancers before they become palpable.
Learning Objectives [1]:
- Understand the various pathologies of breast mass
- Identify risk factors for breast cancer
- Demonstrate relevant physical examination for breast cancer
- Learn the investigation approach (Triple Assessment) and management of breast mass
- Understand the importance of differentiating benign from malignant breast disorders and screening
- Appreciate indications and limitations of investigation tools
- Discuss modalities of treatment: surgery, chemotherapy, radiotherapy, hormonal therapy
1. Breast Cancer Screening
Self breast examination: Regular, formally taught self-examination performed at a monthly interval. Meta-analysis and RCT from Shanghai showed no difference in T stage, and increased false positives. International guidelines NO LONGER recommend regular SBE. Women are advised to be "breast aware" — i.e. aware of changes in their breasts. [2]
Why this matters: SBE sounds intuitively good, but the evidence shows it doesn't downstage cancers and leads to unnecessary biopsies (false positives → anxiety, costs). The shift is from "scheduled self-exam" to "breast awareness" — knowing what's normal for you and seeking help if something changes.
Three RCTs from Philippines and India showed CBE detects smaller tumours but NO data on survival improvement. Cochrane, ACS, and USPSTF all found insufficient evidence to support CBE as a screening tool. [2]
Key point: CBE is still part of clinical assessment when a patient presents with symptoms, but it's not recommended as a population-level screening tool on its own.
ACS systematic review: ~20% reduction in breast cancer mortality in average-risk women. Screening women aged ≥ 50 associated with slightly greater mortality reduction than age < 50. [2]
Harms of mammogram screening [2]:
| Harm | Explanation |
|---|---|
| False positive (overdiagnosis) | Detecting indolent cancers that would never cause symptoms → leads to overtreatment |
| Overtreatment | Unnecessary surgery, chemo, RT for cancers that wouldn't have progressed |
| False negative (false reassurance) | Patient reassured by normal MMG but cancer exists (especially in dense breasts) |
| Radiation | Low-dose X-ray but cumulative risk over years |
| Pain and discomfort | Breast compression during procedure |
Western practice: Age-based screening from 50–69 (extended to 74 in US, Canada, Australia). Mammogram every 2 years. [2]
HK CEWG recommendation: Women aged 44–69 with certain combinations of personalised risk factors should consider mammography screening every 2 years after discussing benefits and harms with their doctors. [2]
HK personalised risk factors for considering screening [2]:
- First-degree relative with breast cancer
- Prior diagnosis of benign breast disease
- Nulliparity or late age of first live birth
- Early age of menarche
- High BMI
- Physical inactivity
Exam Trap: HK vs Western Screening
HK does NOT use a blanket age-based screening for all women. Instead, it uses a risk-stratified approach for women 44–69. This is a favourite exam discriminator — don't just write "mammogram for all women over 50."
2. Clinical Assessment of Breast Conditions
Clinical history must cover: Lump, Pain, Nipple discharge — with further characterisation of duration, changes, unilateral/bilateral, and characteristics. [2]
Symptom characterisation:
| Symptom | Key Questions |
|---|---|
| Lump | Duration, size change, relation to menstrual cycle, pain |
| Pain | Cyclical vs non-cyclical, localised vs diffuse |
| Nipple discharge | Unilateral/bilateral, spontaneous/expressed, colour (bloody/milky/serous), single duct/multiple ducts |
Risk factor history: Familial risks (1st/2nd degree, age of onset), Hormonal risks (menarche/menopause), Gestational history, Breastfeeding history, OCP use, HRT use, Previous breast screening. [2]
Why each risk factor matters:
- Early menarche / late menopause → longer lifetime oestrogen exposure → more proliferative stimulus to breast epithelium
- Nulliparity / late first live birth → breast epithelium doesn't undergo terminal differentiation (which is protective) until first pregnancy
- No breastfeeding → similar concept; breastfeeding suppresses ovulation and promotes terminal differentiation
- OCP/HRT → exogenous oestrogen/progesterone exposure
- Family history → genetic predisposition (BRCA1/2, TP53, PTEN mutations)
- Obesity → peripheral aromatisation of androgens to oestrogens in adipose tissue
- Benign breast disease → atypical ductal/lobular hyperplasia confers 4–5× risk [3]
Examination: Consent / Chaperone / Curtain → Positioning → Exposure → Inspection (symmetry, scars, skin changes, arms raised) → Palpation (breast mass, axillary lymph nodes, nipple discharge if applicable). [2]
Inspection specifics:
- Symmetry — asymmetry may indicate underlying mass
- Scars — previous surgery, biopsy
- Skin changes — peau d'orange (dermal lymphatic invasion → oedema around tethered hair follicles), dimpling (Cooper's ligament tethering by tumour), erythema (inflammatory cancer/abscess), ulceration
- Raising arms — accentuates skin tethering and dimpling by stretching pectoralis fascia
Visual recognition (clinical photograph panel): the deck shows six close-ups that map onto the history/examination checklist — bloody nipple droplet; single-duct milky discharge; scaly/crusted erythematous nipple–areolar change (think Paget's or eczema until proven otherwise); peau d'orange / orange-peel skin; nipple retraction/inversion with surrounding distortion; and another bloody discharge example. Read colour, single vs multi-duct origin, and associated skin/nipple change together — discharge alone is not a diagnosis. [2]
Description of breast lumps: Location (clock face / distance from nipple), Size (precise measurements), Characteristics (border, surface, consistency, tenderness, attachment to skin/muscles). [2]
The lump diagram on the slide points five arrows at one mass (border, surface, consistency, tenderness, attachment) — use that as the OSCE description order, then add clock-face location and measured size. [2]
Describing a lump — a systematic approach:
| Feature | Benign clues | Malignant clues |
|---|---|---|
| Border | Well-defined, smooth | Irregular, ill-defined |
| Surface | Smooth | Irregular |
| Consistency | Soft/rubbery/fluctuant | Hard, stony |
| Tenderness | Often tender (cyst, fibrocystic) | Usually painless (unless advanced) |
| Mobility | Mobile ("breast mouse" for fibroadenoma) | Fixed to skin or chest wall |
Five groups: Anterior (pectoral), Medial (along chest wall), Posterior (subscapular), Lateral (along humerus), Apex (apical/infraclavicular). [2]
Read the axillary diagram: the axilla is drawn as a pyramid with the apex at the top — anterior (pectoral), medial (chest wall), posterior (subscapular), lateral (humeral), and apical groups form the walls/vertex you must systematically clear on examination. [2]
Clinical significance: Palpable hard, fixed, or matted axillary lymph nodes suggest metastatic disease. However, reactive nodes can also be palpable — imaging and biopsy are needed.
Triple Assessment = Clinical (history + examination) + Radiological + Pathological. Sensitivity 99.6%, Specificity 93%. [2]
Why triple assessment? No single modality is perfect. By combining all three, you achieve near-perfect sensitivity. If all three components are concordantly benign, the chance of missing a cancer is extremely low. If ANY component is discordant (e.g., clinical feels benign but radiology is suspicious), you must pursue further investigation.
4. Breast Imaging
USG: Preferred in younger patients, visualises lesions better in dense breasts, characterises breast lumps (cystic vs solid). Mammogram: Characterises calcifications. MRI breasts: See Section 4.3. [2]
Why USG for younger patients? Young women have dense fibroglandular breast tissue. On mammogram, this appears as "white-on-white," making it hard to see a mass. USG uses sound waves that penetrate dense tissue better and can distinguish solid from cystic.
USG features — Benign vs Malignant [2][4]:
| Feature | Benign (e.g. cyst/fibroadenoma) | Malignant |
|---|---|---|
| Shape | Wider than tall | Taller than wide (height > width) |
| Borders | Smooth, well-defined | Irregular outlines, spiculated |
| Internal echo | Homogeneous / anechoic (cyst) | Heterogeneous, hypoechoic |
| Posterior | Posterior enhancement (cyst) | Posterior acoustic shadowing |
| Halo | None | Echogenic halo |
| Vascularity | Minimal | Increased vascularity |
Benign USG findings: Posterior enhancement, homogeneous content. Malignant USG findings: Irregular outlines, height > width, posterior acoustic shadowing, echogenic halo. [2]
What the USG image panels show: benign example — oval, well-circumscribed, homogeneous hypoechoic lesion with labelled posterior enhancement (and a right-axilla oval node/lesion panel); malignant panel — separate frames for irregular outlines, height > width, acoustic shadow, and echogenic halo. Match the label to the geometry rather than memorising the words alone. [2]
High Yield: USG Feature for Malignancy
The 2024 MCQ Q60 tested: "Which USG feature is suspicious for breast cancer?" Answer: Increased vascularity [5]. Other suspicious features include taller-than-wide and acoustic shadowing. Posterior enhancement and homogeneous content are benign features — a common trap.
Mammogram interpretation: Patient name, date, views (CC and MLO), compare both sides. Describe: obvious asymmetry, skin thickness, parenchymal density, mass density, calcification, axillary lymph nodes. [2]
Two standard views [6]:
- Craniocaudal (CC) — top-down compression; good for medial/central lesions
- Mediolateral Oblique (MLO) — angled view; includes axillary tail and axillary LNs
Mammographic features of malignancy [2][6]:
- Mass: Spiculated/stellate, irregular shape, poorly circumscribed
- Calcification: Clusters of pleomorphic microcalcifications, linear/branching microcalcifications
- Other: Architectural distortion, asymmetric density, skin thickening, nipple retraction
Abnormal calcifications: Clusters of pleomorphic microcalcifications are suspicious for malignancy (especially DCIS). [2]
What the mammogram slide shows: left MLO and CC views with arrowheads on a cluster, plus a ×3 magnified inset — teach yourself to localise the cluster on both views before describing morphology. Magnification is how microcalcification shape (pleomorphic vs round/coarse) becomes readable. [2]
Benign vs Malignant calcifications:
| Benign | Malignant |
|---|---|
| Large, coarse ("popcorn-like") | Pleomorphic (varied shapes and sizes) |
| Round, smooth | Irregular, angular |
| Rim-like (e.g. fat necrosis) | Linear, branching (casting-type → fills ducts) |
| Vascular (tramline) | Clustered ( > 5/mm²) |
| Skin calcification |
BI-RADS Classification [6]:
| Category | Assessment | Malignancy Risk | Management |
|---|---|---|---|
| 0 | Incomplete | N/A | Recall for additional imaging |
| 1 | Negative | 0% | Routine screening |
| 2 | Benign | 0% | Routine screening |
| 3 | Probably benign | 1–2% | Short-interval (6-month) follow-up |
| 4 | Suspicious | 3–94% | Tissue diagnosis (biopsy) |
| 5 | Highly suggestive of malignancy | 95–100% | Tissue diagnosis |
| 6 | Biopsy-proven malignancy | N/A | Surgical excision when appropriate |
Exam Point: MMG Limitations
Mammography cannot make a definitive diagnosis — it can only flag lesions as suspicious. Dense breast tissue (young women) reduces sensitivity. This is why USG is preferred in young patients and why the Triple Assessment exists.
Breast MRI indications: Screening high-risk women, patients with implants/augmentation, evaluate equivocal MMG/USG findings, identify occult tumours with positive axillary nodes, monitor neoadjuvant therapy response. [2]
Why MRI? It has the highest sensitivity (88–100%) for breast cancer, especially for invasive lobular carcinoma which can be diffuse and hard to see on MMG/USG. However, it has low specificity — many benign lesions also enhance, leading to unnecessary biopsies. Hence it is NOT a first-line imaging tool [7].
5. Biopsy Techniques
FNAC vs Core Biopsy: [2]
| FNAC | Core Needle Biopsy | |
|---|---|---|
| Type | Cytology | Histopathology |
| Advantages | Safe, simple, inexpensive; immediately distinguishes cysts from solid masses | Distinguishes DCIS from invasive cancer; allows immunohistochemical staining for ER/PR/HER2 |
| Disadvantages | Cannot reliably distinguish DCIS from invasive cancer; cannot perform IHC | Relatively more invasive; requires small stab incision |
Why this distinction matters enormously: Knowing whether a cancer is DCIS vs invasive changes the entire management plan — DCIS doesn't metastasise (it's confined within the basement membrane), so axillary surgery and systemic therapy differ. Also, ER/PR/HER2 status from core biopsy is essential for planning hormonal and targeted therapy.
All biopsy techniques can be guided by: Free hand, Ultrasound, Mammogram (stereotactic), MRI. [2]
| Free hand | USG guided | Stereotactic (MMG) | MRI guided | |
|---|---|---|---|---|
| FNAC | ✓ | ✓ | Won't do | Won't do |
| Core needle biopsy | ✓ | ✓ | ✓ | ✓ |
| Incisional biopsy | ✓ | Not needed | Not needed | Not needed |
| Excisional biopsy | ✓ | ✓ (hookwire) | ✓ (stereotactic hookwire) | ✓ (MRI hookwire) |
Why not FNA with stereotactic/MRI? These guidance methods are used for non-palpable lesions that are only seen on MMG or MRI. If you're going through that complexity, you want the diagnostic certainty of a core biopsy, not just cytology.
Hookwire localisation: For non-palpable lesions, a thin wire is inserted under image guidance before surgery. The surgeon follows the wire to the lesion. Stereotactic hookwire guided excisional biopsy is a classic example [2].
What the operative / specimen images show: multiple localisation wires traversing the excised lump on the drape, then a specimen radiograph with LAT / INF orientation labels confirming the wire tip sits in the calcification cluster. The exam point is not the hardware — it is verifying that the imaged target was actually removed before leaving theatre. [2]
6. Nipple Discharge
Nipple discharge assessment — Symptoms: Unilateral/bilateral, blood-stained/milky/serous, spontaneous/expressed. Signs: Single duct or multiple duct, nature of discharge, any palpable mass or axillary LN. [2]
Risk stratification of nipple discharge:
| Feature | Lower risk | Higher risk (sinister) |
|---|---|---|
| Laterality | Bilateral | Unilateral |
| Ducts | Multiple | Single duct |
| Nature | Milky/serous/green | Blood-stained |
| Spontaneity | On expression only | Spontaneous |
| Mass | No | Yes |
Most common cause of bloody nipple discharge: Intraductal papilloma [8]
Ductoscopy: Allows direct visualisation of the lining of lactiferous ducts via a small fibreoptic scope. [2]
Endoscopic teaching from the slide: the instrument photo sits beside paired duct views — healthy (clean duct, bifurcation) versus diseased (papilloma, high-grade DCIS). Ductoscopy is a visual adjunct for selected pathological discharge; tissue diagnosis and definitive duct excision still drive management. [2]
Microdochectomy: Excision of the diseased duct, usually guided by ductogram/ductoscopy. [2]
Why microdochectomy? It removes the offending duct (often containing a papilloma or DCIS) while preserving the rest of the breast. If the patient is older and not concerned about breastfeeding, total duct excision (Hadfield's procedure) may be considered.
DDx of breast mass: Benign — Fibroadenoma, Cysts, Phyllodes tumour (benign), Others (skin lesions). Malignant — Carcinoma (in situ / invasive), Phyllodes tumour (malignant). [2]
Clinical comparison of common breast lumps [4][9]:
| Age | Pain | Consistency | Mobility | Key feature | |
|---|---|---|---|---|---|
| Fibroadenoma | < 30 | Painless | Firm, rubbery | Very mobile ("breast mouse") | Smooth, lobulated |
| Cyst | 30–55 | May be tender | Soft/firm, fluctuant | Mobile | Sudden onset, smooth, spherical |
| Fibrocystic change | 30–50 | Cyclical pain | Lumpy, nodular | – | Bilateral, fluctuates with cycle |
| Carcinoma | Any (↑ > 50) | Usually painless | Hard, stony | Fixed | Irregular borders, skin changes |
| Phyllodes tumour | 40–50 | Painless | Firm | Mobile initially | Can be large, rapid growth |
| Breast abscess | Lactating | Very painful | Fluctuant | – | Erythema, warmth, fever |
| Fat necrosis | Post-trauma/surgery | May be painful | Firm | Fixed | History of trauma |
8. Breast Cancer Classification
Breast cancers: In-situ carcinoma — DCIS (low/intermediate/high grade). LCIS is a premalignant condition rather than a cancer. [2]
| DCIS | LCIS | |
|---|---|---|
| Frequency | ~20% of all breast CA | Rare |
| Pathology | Malignant cells within TDLU (ductal predominant), no invasion | Malignant cells within TDLU (lobular predominant), no invasion; loss of E-cadherin |
| Focality | Usually unifocal | Usually multifocal + multicentric |
| Imaging | MMG: microcalcifications | Often incidental finding (MMG may be normal) |
| Cancer risk | Precursor to invasive ductal CA of same breast (~1%/year) | Precursor AND marker of bilateral invasive CA (1%/year) |
| Management | BCS (2mm margin) ± RT; or Mastectomy + SLNB; Adjuvant tamoxifen/AI if ER+ | Classical: close observation; Non-classical (pleomorphic): surgical excision |
Why SLNB with mastectomy for DCIS? If you perform mastectomy, you alter lymphatic drainage permanently. If the mastectomy specimen later reveals invasive cancer (10–20% chance of upstaging), you can't do an accurate SLNB afterwards. So you do it at the time of mastectomy [3].
Invasive ductal carcinoma (80%), Invasive lobular carcinoma (3%), Special types: tubular/cribriform, papillary, mucinous, medullary. [2]
Paget's disease: Eczematous changes involving the nipple, associated with malignancy within the same breast. Malignant epithelial (Paget) cells infiltrate and proliferate in the epidermis, causing thickening of the nipple and areolar skin. [2]
Visual recognition: the lecture photograph shows a red, thickened, scaly eczema-like plaque centred on the nipple–areola — unilateral and persistent until the underlying DCIS/invasive cancer is addressed. [2]
Clinical Pearl: Paget's Disease
Any unilateral eczematous nipple change that doesn't respond to dermatological treatment should raise suspicion for Paget's disease. It is almost always associated with an underlying DCIS or invasive cancer. Biopsy the nipple.
| Category | Specific factors |
|---|---|
| Hormonal (unopposed oestrogen) | Early menarche, late menopause, nulliparity, no breastfeeding, OCP, HRT, obesity |
| Familial | 1st degree relative with breast CA (especially if young onset) |
| Genetic | BRCA1/2 (85% lifetime risk), TP53 (Li-Fraumeni), PTEN (Cowden), Peutz-Jeghers |
| Benign breast disease | Atypical ductal/lobular hyperplasia (4–5× risk), sclerosing adenosis, intraductal papilloma, phyllodes tumour |
| Lifestyle | Smoking, alcohol |
10. Management of Breast Cancer
Treatment of cancer (in general): Confirm diagnosis → Stage disease → Assess pre-morbid condition → Optimise nutrition → Definitive treatment (curative or palliative). [2]
10.2 Surgery for Breast Cancer
Two aims: Oncological outcome AND cosmetic outcome [2].
Mastectomy: Removal of entire breast. Types: Simple mastectomy (linear scar), Skin-sparing mastectomy (usually with reconstruction), Nipple-sparing mastectomy (NSM — selected low-risk patients, no nipple involvement, prophylactic mastectomy). [2]
Lumpectomy (Breast Conserving Surgery, BCS): Removal of cancer with margin. 2mm margin for in-situ cancer, no cancer at inked margin for invasive cancer. Intraoperatively aim 5–10mm margin. Balance between cosmetic and oncologic outcome. Breast Conserving Treatment (BCT) = Lumpectomy + Radiation. [2]
Critical Concept: BCS + RT = BCT
Lumpectomy alone is NOT adequate treatment. It must be combined with adjuvant radiotherapy to reduce local recurrence. This combination (BCT) has equivalent survival to mastectomy for appropriately selected patients.
Current-Practice Update
Keep the final pathology margin separate from the intraoperative aim. SSO–ASTRO: invasive cancer needs no ink on tumour; DCIS treated with whole-breast RT uses a 2 mm standard, and routinely chasing wider than 2 mm is not required. The slide's "usually aim 5–10 mm in theatre" is surgical working margin, not a reason to re-excise every closer but negative final margin. [2][16]
Oncoplastic surgery (American Society of Breast Surgeons consensus classification on the slide): a form of breast-conservation surgery that combines oncological resection (partial mastectomy) with ipsilateral reconstruction using volume displacement or volume replacement techniques, with possible contralateral symmetry surgery [2].
| Classification | Tissue Removed | Examples |
|---|---|---|
| Volume displacement — Level 1 | < 20% breast tissue | Local tissue rearrangement, crescent mastopexy, doughnut mastopexy |
| Volume displacement — Level 2 | 20–50% breast tissue | Circumvertical mastopexy design, reduction mammaplasty designs (including free nipple graft) |
| Volume replacement | > 50% breast tissue | Implant-based reconstruction, local/regional flap reconstruction (e.g. thoracodorsal artery perforator) |
Axillary Dissection (AD): Removal of level I & II lymph nodes. Pectoralis minor is the landmark. Preservation of: Long thoracic nerve (serratus anterior — winged scapula), Thoracodorsal nerve (latissimus dorsi), Intercostobrachial nerves (sensation of medial arm/axilla). [2]
Complications of AD [2]:
- Lymphoedema (10–20% risk) — most feared long-term complication
- Nerve injuries (long thoracic → winged scapula; thoracodorsal → latissimus dorsi weakness; intercostobrachial → medial arm/axillary sensory loss)
- Frozen shoulder
- General surgical complications (skin infection, scarring)
Sentinel Lymph Node Biopsy (SLNB): Cancer cells travel along lymphatic channels step-by-step (like railway stations). The first node to receive drainage is the "sentinel" — if it's negative, the rest are very likely negative too. [2]
Why SLNB is revolutionary: It spares many patients from full axillary dissection (and its complications, especially lymphoedema) when the axilla is pathologically negative or only minimally involved under modern selection rules.
Current-Practice Update
Do not treat every positive sentinel node as an automatic ticket to completion AD. For early clinically node-negative disease with 1–2 positive SLNs undergoing BCS + whole-breast RT (± systemic therapy), ACOSOG Z0011 / current ASCO guidance support omitting routine ALND. Completion AD remains for heavier axillary burden, mastectomy pathways where nodal RT/systemic decisions require it, or when eligibility criteria are not met. [17]
SLN Identification Methods [2]:
- Blue dye (patent blue) — injected around tumour, travels to SLN, surgeon looks for blue node
- Radioisotope — injected pre-op, detected intraoperatively with gamma probe
- Others: Supramagnetic iron oxide (SPIO), Indocyanine green (ICG)
Four main surgical strategies: (1) Mastectomy + SLNB, (2) Mastectomy + AD (Modified Radical Mastectomy/MRM), (3) BCS + SLNB, (4) BCS + AD. [2]
Lecture mnemonic (food grid): burger size = breast operation (large = mastectomy, small = BCS); drink size = axillary operation (small cup = SLNB, large cup = AD). The 2×2 is a teaching cartoon for the four combinations — not a ranking of which meal is "best." [2]
Choice depends on:
- Tumour size and location
- Multifocality/multicentricity
- Patient preference
- Breast size (cosmetic outcome of BCS)
Multifocal vs Multicentric [3]:
- Multifocal: ≥2 foci in the same quadrant → NOT a contraindication to BCT
- Multicentric: ≥2 foci in different quadrants → contraindication to BCT (mastectomy needed)
After NAC: Mastectomy or BCS depends on tumour response, breast size, tumour location and multiplicity, and patient's preference. [2]
The slide's punchline — "My preference matters" — is deliberate: after response assessment, shared decision-making (cosmesis, reconstruction plans, risk tolerance) sits alongside the oncological factors, not beneath them. [2]
Reconstruction: Implant-based, Autologous tissue-based (Latissimus dorsi flap, TRAM flap), or mixture of both. [2]
Radiotherapy indications: Locally advanced cancer (lymph node involvement), large tumours, high-grade tumours, lymphovascular permeation, and after breast conserving surgery. [2]
Why RT after BCS? Local recurrence rate after lumpectomy alone is unacceptably high (~30–40%). RT reduces this to ~5–10%, making BCS + RT equivalent to mastectomy in survival.
Chemotherapy indications: Adjuvant/neoadjuvant for locally advanced (LN involvement, large tumour), high-risk (young age, triple-negative, HER2+), and palliative. [2]
Why neoadjuvant? Given before surgery to shrink the tumour → may convert a patient who needs mastectomy into a BCS candidate. Also allows assessment of chemosensitivity in vivo.
Tamoxifen vs Aromatase Inhibitor. Can be adjuvant or palliative. Use in DCIS remains controversial. [2]
Why the distinction?
- Tamoxifen = selective oestrogen receptor modulator (SERM); blocks ER in breast tissue. Used in pre- and postmenopausal women.
- Aromatase inhibitor (e.g. letrozole, anastrozole) = blocks conversion of androgens to oestrogens in peripheral tissues. Only works in postmenopausal women (premenopausal women still produce oestrogen from ovaries).
HER2-positive breast cancer → Trastuzumab (Herceptin), a monoclonal antibody against HER2 receptor. Requires confirmation by IHC and/or FISH [11].
HER2 Testing [11]:
- IHC on formalin-fixed paraffin section of invasive breast cancer
- If equivocal (IHC 2+), confirm with FISH (fluorescence in situ hybridisation)
- FISH positive: HER2/CEP17 ratio ≥ 2.0 and/or HER2 copy number ≥ 6.0
A core biopsy pathology report provides the information needed to plan definitive treatment. Key elements illustrated by a sample report [2]:
| Report Element | What to Look For |
|---|---|
| Tumour subtype | e.g. Invasive ductal carcinoma, no special type (most common — 80%) |
| Invasiveness | Infiltrative adenocarcinoma vs in-situ only |
| Grade components | Tubule formation, nuclear pleomorphism, mitotic count |
| Lymphovascular permeation | Present or absent — affects staging and adjuvant decisions |
| Perineural invasion | Present or absent |
| E-cadherin | Positive → ductal differentiation; Negative → lobular differentiation |
| ER / PR status | Scored by intensity and % nuclei positive; guides hormonal therapy |
| HER2 status | IHC score 0/1+ = negative; 2+ = equivocal (→ FISH); 3+ = positive |
| Ki-67 / Proliferative index | High proliferative index (e.g. 60%) indicates aggressive biology |
Worked example from the lecture pathology slide (annotations: tumour subtype / invasiveness / immunohistochemistry) [2]:
- Right breast cores → infiltrative adenocarcinoma, invasive ductal carcinoma, no special type
- Minimal tubule formation, moderate nuclear pleomorphism, mitoses < 8/10 HPF; no LVI, no perineural invasion, no DCIS in the cores shown
- E-cadherin diffusely positive (ductal); p63 negative around invasive foci (supports true invasion / loss of myoepithelium)
- Proliferative index ~60%
- ER 0 / PR 0 / HER2 IHC 0 → triple-negative biology → systemic therapy centred on chemotherapy rather than endocrine or anti-HER2 agents
A triple-negative breast cancer (ER−, PR−, HER2−) lacks targets for hormonal and anti-HER2 therapy, making chemotherapy the mainstay of systemic treatment. [2]
12. Exam Intelligence
| Trap | Correct Understanding |
|---|---|
| "SBE reduces mortality" | NO — no mortality benefit, only increases false positives |
| "USG is the screening tool" | NO — MMG is for screening; USG is for diagnostic/young patients |
| "FNAC can tell DCIS vs invasive" | NO — only core biopsy can distinguish |
| "BCS alone is adequate" | NO — must add RT (BCT = BCS + RT) |
| "Any positive SLN → always do AD" | NO — selected early disease with 1–2 positive SLNs + BCS + WBRT can omit routine ALND (Z0011/ASCO) |
| "All women > 40 should get MMG in HK" | NO — HK uses risk-stratified approach (44–69 with risk factors) |
| "Posterior enhancement = malignant" | NO — posterior enhancement is a benign USG feature (cyst) |
| "Peau d'orange = infection" | Can occur in infection BUT the exam answer is inflammatory breast cancer |
| "MMG preferred for 25-year-old" | NO — USG is the first-line imaging in young women (dense breasts) |
- Progressive breast lump enlargement = sinister [10] vs cyclical pain / bilateral serous discharge / bilateral engorgement = benign
- Increased vascularity on USG = suspicious [5] vs posterior enhancement / homogeneous content = benign
- USG is the most appropriate initial imaging for a 25-year-old with a breast lump [10]
AOS Pathology — HER2 Testing [11]
Question
"A 56-year-old lady was diagnosed by core biopsy to have invasive carcinoma of the breast, grade 3."
High Yield Summary
-
Screening
- HK uses risk-stratified approach (44–69 with risk factors → MMG q2y). SBE and CBE are NOT recommended as screening tools. MMG screening reduces BC mortality by ~20%.
-
Triple Assessment
- (Clinical + Radiological + Pathological) = sensitivity 99.6%. All three must be concordant.
-
Imaging choice
- USG for young/dense breasts; MMG for calcifications and screening; MRI for high-risk, implants, occult primary, neoadjuvant monitoring.
-
FNAC vs Core Bx
- Core biopsy is preferred when malignancy is suspected — it distinguishes DCIS from invasive and allows ER/PR/HER2 testing.
-
Breast cancer types
- IDC (80%), ILC (3%), DCIS, LCIS (premalignant marker, not cancer), Paget's disease (nipple eczema = underlying malignancy).
-
Surgery
- BCS + RT (BCT) or Mastectomy. Axillary: SLNB for clinically node-negative staging; do not equate every positive SLN with mandatory AD (Z0011/ASCO exceptions for limited SLN disease + BCS + WBRT). Preserve long thoracic, thoracodorsal, and intercostobrachial nerves.
-
Margins
- Final pathology: DCIS 2 mm (with WBRT); invasive = no ink on tumour. Intraoperative 5–10 mm aim ≠ automatic re-excision threshold.
-
Adjuvant therapy
- RT after BCS (always), and for large/high-grade/node-positive tumours. Chemo for locally advanced, triple-negative, HER2+. Hormonal therapy (tamoxifen pre-menopause, AI post-menopause) for ER+ disease.
-
Key USG malignant features
- Taller than wide, irregular borders, posterior acoustic shadowing, echogenic halo, increased vascularity.
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Key MMG malignant features
- Spiculated mass, clustered pleomorphic microcalcifications, architectural distortion.
Active Recall - Breast Mass & Breast Cancer
[1] Lecture slides: Case 1 - Breast mass.pdf (Learning Objectives, p2) [2] Lecture slides: GC 181. Breast mass breast cancer; benign breast diseases; mammography; breast cancer screening.pdf (p1–p50) [3] Senior notes: Maksim Surgery Notes.pdf (p181–183) [4] Senior notes: Ryan Ho Urogenital.pdf (p190, p195–196) [5] Past papers: 2024 Fourth Summative MCQ.pdf (Q22, Q60) [6] Senior notes: MBBS Final MB (Surgery) (Felix PY Lai).pdf (p303–305) [7] Senior notes: Ryan Ho Fundamentals.pdf (p375) [8] Past papers: 2017 Fourth Summative SAQ.pdf (Q7) [9] Senior notes: Ryan Ho Radiology.pdf (p29) [10] Past papers: 2025 Fourth Summative MCQ.pdf (Q21, Q23, Q69) [11] AOS material: AOS - Pathology.pdf (p43) [16] SSO–ASTRO (with ASCO for DCIS) consensus guidelines on margins for breast-conserving surgery with whole-breast irradiation (invasive: no ink on tumour; DCIS: 2 mm standard) [17] ASCO guideline update on sentinel lymph node biopsy in early-stage breast cancer; ACOSOG Z0011 (Alliance) — omission of routine ALND for selected patients with 1–2 positive sentinel nodes undergoing BCS + whole-breast RT
GC180 Benign Prostatic Hyperplasia, Bladder Outlet Obstruction And Urinary Retention
Benign prostatic hyperplasia is a non-malignant enlargement of the prostate gland that can cause bladder outlet obstruction and, if untreated, may progress to acute or chronic urinary retention.
GC182 Chopped And Stabbed Wound In Gang Fight Nerves And Vascular Injury; Classification Of Injuries
Chopped and stabbed wounds sustained in gang fights involving nerve and vascular damage are classified based on wound mechanism (incised, stab, or chop), depth of penetration, and severity of neurovascular injury to guide medicolegal documentation and surgical management.