What are the indications, pre‑operative workup, surgical options, and postoperative management for mastectomy in invasive breast cancer?

Mastectomy for Invasive Breast Cancer

Mastectomy is indicated when breast-conserving therapy is contraindicated or not feasible, specifically for: diffuse suspicious/malignant microcalcifications, widespread disease not amenable to single-incision excision with negative margins and acceptable cosmesis, diffusely positive margins after re-excision attempts, radiation therapy contraindications (including pregnancy), inflammatory breast cancer, or patient preference 1.

Absolute Indications for Mastectomy

The following situations mandate mastectomy over breast-conserving surgery:

• Radiation therapy during pregnancy - absolute contraindication to breast conservation 1
• Diffuse suspicious or malignant-appearing microcalcifications throughout the breast 1
• Widespread disease that cannot be incorporated through a single incision achieving negative margins with satisfactory cosmetic result 1
• Diffusely positive pathologic margins despite re-excision attempts 1
• Inflammatory breast cancer (T4d) 2, 3

Relative Indications

• Patient preference for mastectomy over breast conservation, particularly in high-risk patients 2, 3
• Contraindication to radiotherapy (beyond pregnancy) 3
• Multiple surgical attempts with persistent positive margins 3
• Multifocal tumors requiring multiple incisions that cannot achieve acceptable cosmetic outcome 3
• Poor expected aesthetic results from conservative surgery 3

Pre-operative Workup

Before proceeding to mastectomy:

• Metastatic screening must be performed to rule out distant disease 2
• Histological diagnosis confirmation is mandatory before surgery 3
• Evaluation of reconstructive options should be discussed preoperatively with all patients 1
• Assessment of axillary nodal status through clinical examination and imaging
• Review of imaging studies (mammography, ultrasound, MRI if indicated) to determine disease extent

Critical timing requirement: Surgery should occur within 6 weeks of diagnostic mammography 3.

Surgical Options

Types of Mastectomy

Modified radical mastectomy remains the standard approach, which includes:

• Complete breast tissue removal
• Levels I and II axillary lymph node dissection 2

Skin-sparing mastectomy is acceptable when:

• Performed by experienced multidisciplinary breast surgery teams 1
• Appropriate patient selection ensures adequate surgical margins 1
• Post-mastectomy radiation criteria remain the same as standard mastectomy 1
• Not recommended for inflammatory breast cancer due to need for skin resection 1

Nipple-areolar complex (NAC)-sparing procedures may be considered for:

• Early-stage, biologically favorable tumors (Nottingham grade 1-2, node-negative, HER2-negative, no lymphovascular invasion) 1
• Peripherally located disease (>2 cm from nipple) 1
• Mandatory nipple margin assessment with clearly designated margins 1
• Contraindicated if Paget's disease, nipple discharge with malignancy, or imaging suggests nipple/subareolar involvement 1

Axillary Management

• Axillary dissection (levels I and II) should be performed after invasive carcinoma confirmation 2
• Sentinel lymph node biopsy is standard for clinically node-negative patients 4
• Complete axillary dissection reserved for high disease burden or when impacting adjuvant treatment decisions 4

Reconstruction Considerations

All women undergoing mastectomy should be educated about reconstructive options 1.

Reconstruction Options Include:

1. Implant-based reconstruction

   • Tissue expander followed by permanent implant
   • Immediate implant placement 1

2. Autologous tissue reconstruction

   • Pedicled TRAM flap
   • Microsurgical flaps (abdomen, back, buttocks, thigh)
   • Fat grafting 1

3. Combined approaches (implants plus autologous tissue, e.g., latissimus dorsi flaps) 1

Timing of Reconstruction

Immediate reconstruction (at time of mastectomy):

• Absolutely contraindicated for inflammatory breast cancer due to high recurrence risk and need for expeditious post-operative radiotherapy 1
• Can be offered for non-inflammatory cases if no other high-risk features for locoregional recurrence 2
• Should not delay appropriate adjuvant treatments 2, 4

Delayed reconstruction (after completion of cancer treatment):

• Preferred when post-mastectomy radiation is required 1
• In previously irradiated patients, autologous tissue is strongly preferred over tissue expanders/implants due to significantly increased risk of capsular contracture, malposition, poor cosmesis, and reconstruction failure 1

Important Reconstruction Caveats

• Reconstruction should never interfere with appropriate surgical cancer management 1
• Reconstruction should not govern timing or scope of appropriate surgical treatment 1
• Most reconstructions require staged approach with multiple procedures including contralateral breast surgery for symmetry, revision surgery, and nipple-areola reconstruction 1
• If post-mastectomy radiation is required with autologous reconstruction planned, either delay reconstruction until after radiation or initiate with tissue expander followed by autologous reconstruction 1

Post-operative Management

Radiation Therapy

Post-mastectomy radiation therapy (PMRT) is indicated for:

• High-risk features 4:

  • Involved resection margins
  • ≥4 involved axillary lymph nodes
  • T3-T4 tumors
  • Combinations of other risk factors

• Intermediate-risk features (consider PMRT) 4:

  • 1-3 positive axillary lymph nodes
  • Lymphovascular invasion
  • Young age

Chest wall radiotherapy should be performed when risk factors are present 2.

Nodal radiotherapy (infraclavicular, supraclavicular, internal mammary chain):

• Recommended for patients with involved lymph nodes 2, 4
• Extent depends on number of involved nodes, N-stage, and response to neoadjuvant therapy 4

Hypofractionated schedules are recommended 4:

• Moderate: 15-16 fractions of 3 Gy per fraction
• Ultra-hypofractionated: 26 Gy in 5 daily fractions for chest wall without reconstruction

Quality and Safety Indicators

Four critical quality metrics apply 3:

1. Surgery must be performed after obtaining histological diagnosis
2. Surgery must occur within 6 weeks of mammography
3. Single surgery should achieve clear margins in >80% of cases
4. Radiotherapy must follow when indicated

Follow-up Considerations

• Monitor for local-regional recurrence (skin-sparing mastectomy has equivalent recurrence risk to standard mastectomy) 1
• Assess for surgical complications: seroma, infection, hematoma, flap necrosis, wound dehiscence 5
• Evaluate reconstruction outcomes if performed
• Coordinate systemic adjuvant therapy based on final pathology

Common Pitfalls to Avoid

• Do not delay mastectomy for reconstruction planning—cancer treatment takes priority 1
• Do not perform immediate reconstruction in inflammatory breast cancer 1
• Do not use tissue expanders/implants in previously irradiated fields—use autologous tissue 1
• Do not omit post-mastectomy radiation in skin-sparing or NAC-sparing procedures when standard criteria are met 1
• Do not perform axillary dissection before confirming invasive carcinoma 2
• Do not preserve nipple-areolar complex without mandatory margin assessment 1