Malignancy of the Breast: A Case-Based Approach

This section provides a comprehensive, case-based overview of breast cancer, organized into Introduction, Clinical Presentation, Examination, Investigations, Staging, Surgical Management, and Prognostic Factors. All information is derived strictly from the provided texts, ensuring accuracy and avoiding external additions.

1. Introduction

Breast cancer is the most common noncutaneous cancer in women, accounting for 30% of all female cancers in the US. It is the second leading cause of cancer death in women, surpassed only by lung cancer. One in eight women will develop breast cancer during their lifetime. The disease arises from the epithelium of the duct system, ranging from the nipple end of the major lactiferous ducts to the terminal duct unit in the breast lobule. Breast cancer may present as in situ carcinoma (confined to ducts or lobules) or invasive carcinoma (penetrating the basement membrane). Below is complete overview of the malignancy of the breast.

2. Clinical Presentation

Common Symptoms

• Hard lump in the breast, most frequently in the upper outer quadrant.
• Nipple changes: Retraction, discharge, or erosion (e.g., Paget’s disease).
• Skin changes: Peau d’orange (dimpled skin resembling an orange peel), ulceration, or fixation to the chest wall.
• Pain and swelling: Inflammatory breast cancer presents with a painful, swollen, warm breast with cutaneous edema.

Advanced Disease

• Locally advanced breast cancer (LABC): Tumors involving the chest wall, skin, or extensive lymph node involvement.
• Metastatic disease: Symptoms related to distant metastases (e.g., bone pain, liver dysfunction, neurological symptoms).

3. Examination

Physical Examination

• Inspection:
  • Assess for asymmetry, skin changes (e.g., erythema, peau d’orange), nipple retraction, or ulceration.
• Palpation:
  • Evaluate the breast for lumps, noting size, location, mobility, and tenderness.
  • Examine axillary, supraclavicular, and internal mammary lymph nodes for enlargement or fixation.

Special Findings

• Paget’s disease of the nipple: Eczema-like condition with nipple erosion.
• Inflammatory breast cancer: Erythema, warmth, and edema involving at least one-third of the breast.

4. Investigations

Diagnostic Workup

1. Imaging:
   • Mammography: Detects clustered pleomorphic calcifications (DCIS) or masses.
   • Ultrasound: Differentiates solid masses from cysts.
   • MRI: Useful for assessing tumor extent, multifocality, and response to neoadjuvant therapy.
   • CT scan: Evaluates distant metastases in advanced disease.
   • Bone scan: Detects skeletal metastases if alkaline phosphatase or calcium levels are elevated.
2. Biopsy:
   • Core needle biopsy (CNB): Preferred for histopathological diagnosis.
   • Skin punch biopsy: Confirms inflammatory breast cancer or Paget’s disease.
3. Laboratory Tests:
   • Complete blood count, liver function tests (LFTs), and calcium levels.
   • Tumor markers: ER, PR, HER2/neu, and Ki-67.

5. Staging

Breast cancer staging follows the American Joint Committee on Cancer (AJCC) TNM system, which evaluates:

1. Tumor size and chest wall involvement.
2. Level and extent of lymph node metastases.
3. Presence or absence of distant metastases.

Workup for Staging

• Clinical stage I/II: Physical examination, mammography, and ultrasound.
• Clinical stage III/IV: Bone scan, CT of the chest/abdomen/pelvis, and MRI if indicated.

6. Surgical Management

Ductal Carcinoma In Situ (DCIS)

• Treatment:
  • Partial mastectomy with negative margins (>2 mm) followed by whole breast irradiation.
  • Total mastectomy for multicentric lesions or extensive involvement.
• Adjuvant therapy:
  • Radiation reduces local recurrence but does not impact survival.
  • Hormone therapy for ER-positive DCIS.

Invasive Breast Cancer

1. Breast Conservation Therapy (BCT):
   • Partial mastectomy with adjuvant radiation.
   • Contraindications:
     • High tumor-to-breast-size ratio.
     • Inability to achieve negative margins.
     • Contraindications to radiation (e.g., pregnancy, prior chest radiation).
2. Mastectomy:
   • Simple mastectomy: Removal of breast tissue, nipple, and areola.
   • Modified radical mastectomy: Includes axillary lymph node dissection (ALND).
   • Skin-sparing or nipple-sparing mastectomy: Preserves skin envelope for reconstruction.

Surgical Steps for Simple Mastectomy

1. Positioning: Supine, arms out.
2. Incision: Elliptical incision around the nipple-areolar complex.
3. Skin Flaps: Raised to clavicle, rectus sheath, sternal border, and latissimus dorsi muscle.
4. Tissue Removal: Breast tissue dissected off pectoral fascia.
5. Hemostasis: Surgical drain placed.
6. Closure: Incision closed in layers.

Axillary Management

1. Sentinel Lymph Node Biopsy (SLNB):
   • Indicated for clinically node-negative patients.
   • Combines blue dye and radioisotope for higher sensitivity.
2. Axillary Lymph Node Dissection (ALND):
   • Indicated for clinically positive nodes.
   • Levels I and II nodes removed; level III if grossly involved.

7. Prognostic Factors

Key Prognostic Indicators

1. Tumor size and grade:
   • Larger tumors and higher grades correlate with worse outcomes.
2. Lymph node status:
   • Presence of nodal metastases is the single most important prognostic factor.
3. Molecular markers:
   • ER/PR-positive: Better prognosis; responsive to hormone therapy.
   • HER2-positive: Poor prognosis but responsive to targeted therapies.
   • Triple-negative: Aggressive subtype with limited treatment options.

Genomic Tools

• Oncotype Dx: Analyzes 21 genes to predict recurrence risk and guide adjuvant chemotherapy.

8. Special Considerations

Inflammatory Breast Cancer

• Presentation: Painful, swollen breast with erythema and edema.
• Diagnosis: Skin punch biopsy confirms dermal lymphatic involvement.
• Treatment: Neoadjuvant chemotherapy followed by mastectomy and radiation.

Paget’s Disease of the Nipple

• Presentation: Eczema-like nipple erosion.
• Diagnosis: Biopsy shows Paget cells in the epidermis.
• Treatment: Mastectomy or breast-conserving surgery with radiation.

Locally Advanced Breast Cancer (LABC)

• Definition: Tumors involving chest wall, skin, or extensive lymph nodes.
• Treatment: Neoadjuvant chemotherapy, surgery, and radiation.

9. Follow-Up and Surveillance

• Physical examination: Every 3-6 months for the first 5 years, then annually.
• Mammography: Annually for the treated and contralateral breast.
• Monitoring for recurrence: Bone scan, CT, or MRI if symptomatic.

10. Prognosis

• Early-stage disease: 5-year survival >90% with appropriate treatment.
• Locally advanced disease: 5-year survival ~50-70%.
• Metastatic disease: Median survival ~2-3 years.