What is the role of radiation therapy in the treatment of inflammatory breast cancer?

Role of Radiation Therapy in Inflammatory Breast Cancer

Radiation therapy is an essential component of the multimodality treatment approach for inflammatory breast cancer (IBC) and should be administered to all patients following modified radical mastectomy to reduce locoregional recurrence and improve survival outcomes. 1

Standard Treatment Sequence for IBC

The management of inflammatory breast cancer follows a specific sequence:

1. Primary (Neoadjuvant) Systemic Chemotherapy

   • First-line treatment to downstage the tumor
   • Anthracycline and taxane-based regimens recommended
   • Addition of trastuzumab for HER2-positive disease 1

2. Surgery

   • Modified radical mastectomy is the standard surgical approach
   • Skin-sparing mastectomy is contraindicated
   • Breast-conserving approaches should only be considered within clinical trials 1
   • Sentinel lymph node biopsy is not reliable in IBC; axillary dissection is preferred 1

3. Radiation Therapy

   • Mandatory component following mastectomy 1

Radiation Therapy Protocol for IBC

Target Volumes

• Chest wall
• Supraclavicular region
• Infraclavicular region
• Internal mammary lymph nodes
• Any part of the axillary bed at risk 1

Dose Recommendations

• Standard fractionation: 1.8-2.25 Gy per fraction (median 2 Gy) 2
• Total dose escalation to 66 Gy recommended for high-risk patients:
  • Age <45 years
  • Close or positive surgical margins
  • ≥4 positive lymph nodes after preoperative chemotherapy
  • Poor response to preoperative systemic treatment 1

Technical Considerations

• Aggressive use of bolus (typically 1-cm bolus daily throughout treatment) 2
• Skin dose should be modulated to ensure moderate acute erythema 1
• Boost to the mastectomy scar often recommended 2
• Once-daily radiation therapy with aggressive bolus use shows outcomes consistent with intensified regimens 2

Outcomes and Prognostic Factors

With trimodality treatment including radiation therapy, outcomes include:

• 5-year locoregional control: 81% 2
• 5-year disease-free survival: 56% 2
• 5-year overall survival: 64% 2

Poor prognostic factors include:

• Extracapsular extension 2
• Age ≤50 years 2
• Lack of complete response to chemotherapy 2

Timing of Radiation Therapy

Radiation therapy typically follows chemotherapy when chemotherapy is indicated 1. For patients with HER2-positive disease, trastuzumab may be administered concomitantly with radiation therapy 1.

Special Considerations

Breast Reconstruction

• Immediate reconstruction is not recommended as it may limit radiation coverage and compromise treatment of internal mammary lymph nodes 1
• Delayed reconstruction should be considered after completion of radiation therapy

Monitoring Response

• Regular imaging during and after treatment is important to assess response
• Ultrasound of locoregional lymph nodes may be considered during follow-up 1

Follow-up Recommendations

After completing trimodality treatment:

• Physical examinations every 3-6 months
• Yearly mammogram of the contralateral breast
• Consider yearly ultrasound of locoregional lymph nodes 1

Radiation therapy remains a critical component in the management of inflammatory breast cancer, with once-daily treatment and aggressive bolus use providing effective local control when integrated into a comprehensive treatment approach.