Special Surgery 32. Breast Cancer: Diagnostics and Treatment

I. Overview, Types and Spread

Definition and Epidemiology

Breast cancer: malignant tumor derived from breast epithelial tissue
Most commonly ductal or lobular epithelium
Most common cancer in women
Major cause of cancer-related death in women
Rare in men

Classification

Invasive / infiltrating breast cancer

Invasive ductal carcinoma (IDC) / no special type → about 80%
Invasive lobular carcinoma (ILC) → about 15%
Less common: tubular, mucinous, medullary-like, inflammatory breast cancer

In situ and special forms

Ductal carcinoma in situ (DCIS): malignant ductal cells without basement membrane invasion
Lobular carcinoma in situ (LCIS): lobular neoplasia, mainly risk marker
Paget disease: malignant cells in nipple/areola epidermis, usually with underlying DCIS or invasive cancer

Etiology / Risk Factors

Aging and female sex
Family history, BRCA1/BRCA2 mutations
Hormonal factors: early menarche, late menopause, nulliparity/late first pregnancy, hormone replacement therapy
Previous chest radiation exposure
Lifestyle: obesity after menopause, alcohol, smoking, physical inactivity

Spread

Lymphatic spread: axillary nodes → supraclavicular/infraclavicular and internal mammary nodes
Hematogenous metastases: bone, liver, lung/pleura, brain
Axillary lump → lymph node involvement until proven otherwise

II. Clinical Features, Diagnosis and Staging

Clinical Features

Often asymptomatic → screening mammography
Painless breast lump
Nipple retraction or bloody/serous discharge
Skin changes: dimpling, erythema, thickening, ulceration
Peau d'orange: lymphatic obstruction
Palpable axillary/supraclavicular nodes
Inflammatory breast cancer: rapid diffuse redness, edema, warmth; may mimic mastitis
Paget disease clue: persistent nipple eczema/erythema, retraction or bloody discharge

Triple Diagnosis

Medical history + physical examination

Inspection: asymmetry, skin changes, scars, mass, nipple changes
Palpation: begin with normal breast → lump size, location, mobility, consistency, tenderness
Palpate axillary, supraclavicular and infraclavicular nodes

Imaging

Mammography: first-line screening/diagnostic test, especially >40 years
Mammography findings: mass, microcalcifications, architectural distortion, asymmetry
Ultrasound: younger women/dense breasts, cystic vs solid, axillary nodes, biopsy guidance
MRI: high-risk patients, dense breasts/extent uncertainty, implants, response after neoadjuvant therapy

Biopsy / pathology

Core needle biopsy: preferred for histological diagnosis
Fine-needle aspiration biopsy (FNAB): less used; cytology only
Pathology: tumor type, grade, invasion, margins, ER, PR, HER2, Ki-67

Staging

TNM: tumor size/local extension + lymph nodes + distant metastasis
T stage:

Tis: in situ disease
T1: <=2 cm
T2: >2-5 cm
T3: >5 cm
T4: chest wall/skin involvement or inflammatory breast cancer

N stage: N0 no regional nodes; N1-N3 increasing axillary/internal mammary/supraclavicular nodal disease
M stage: M0 no distant metastasis; M1 distant metastasis
Staging investigations: CT, bone scan or PET-CT if advanced stage, node-positive/high-risk disease or metastatic symptoms
Genetic testing if young age, strong family history, triple-negative cancer, bilateral disease or male breast cancer

III. Treatment of Invasive Breast Cancer

General Principles

Treatment planned by multidisciplinary breast team
Decision depends on tumor stage, breast size, nodal status, ER/PR/HER2/Ki-67, age, menopausal status and patient preference
Main modalities: surgery, radiotherapy, endocrine therapy, chemotherapy, targeted therapy

1. Surgery

Breast-conserving surgery (BCS) / lumpectomy:

For many early cancers if clear margins and acceptable cosmesis possible
Usually followed by radiotherapy

Mastectomy:

Simple mastectomy: breast tissue removed
Modified radical mastectomy: breast tissue + axillary lymph node dissection
Indications: large tumor relative to breast, multicentric disease, contraindication to radiotherapy, patient preference

Axillary surgery:

Sentinel lymph node biopsy (SLNB): standard for clinically node-negative invasive cancer
Axillary lymph node dissection (ALND): node-positive disease or selected positive SLNB/high nodal burden

2. Radiotherapy

After BCS: usually required
After mastectomy: high-risk cases, e.g. large tumor, positive margins, multiple positive nodes
Regional nodal irradiation in selected node-positive/high-risk disease

3. Systemic Therapy

Hormone receptor positive disease:

Tamoxifen: especially premenopausal
Aromatase inhibitors: anastrozole/letrozole/exemestane, mainly postmenopausal
Ovarian suppression may be added in higher-risk premenopausal patients

HER2-positive disease:

Trastuzumab + chemotherapy
More aggressive biology, but targeted therapy improves prognosis
Monitor cardiac function

Chemotherapy:

Triple-negative tumors
High-grade, large or node-positive tumors
Common drug groups: anthracyclines, e.g. doxorubicin/epirubicin; taxanes, e.g. paclitaxel/docetaxel

Neoadjuvant and Adjuvant Therapy

Neoadjuvant therapy: before surgery → shrink tumor, enable BCS, treat/downstage nodes
Useful for large/inoperable tumors and many HER2-positive or triple-negative cancers
Adjuvant therapy: after surgery → reduce recurrence risk
Choice depends on stage + biomarkers + patient factors

IV. Follow-Up and Exam Summary

Special Exam Points

DCIS: non-invasive ductal malignancy, usually screening microcalcifications → local treatment; mastectomy if extensive
LCIS: incidental lobular neoplasia/risk marker → surveillance ± risk-reducing endocrine therapy
Paget disease: persistent nipple/areola eczema-like change → nipple biopsy + image breast; treat underlying DCIS/invasive cancer

Follow-Up

Regular clinical follow-up and annual mammography of remaining breast tissue
No routine CT/PET/tumor markers in asymptomatic early breast cancer follow-up
Monitor endocrine therapy side effects, bone health, lymphedema and shoulder function

Exam focus: Diagnosis is triple diagnosis: clinical assessment, imaging and core biopsy. Treatment is stage + biology based. Early invasive cancer often gets lumpectomy + radiotherapy + sentinel lymph node biopsy, or mastectomy if breast conservation is unsuitable. ER-positive gets endocrine therapy; HER2-positive gets trastuzumab; triple-negative/high-risk tumors need chemotherapy.