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SSO/ASTRO Guideline on Margins for Breast-Conserving Surgery (BCS) with Whole-Breast Irradiation (WBI) in Stages I and II Invasive Breast Cancer

Published: March 2014

Read Full-Text Guideline

This collaborative guideline considers several questions related to defining margins for patients who have reached breast-conserving surgery and WBI. It delineates when margins are positive and the necessary width to consider the margin negative. It also addresses the interaction between margin width and systemic therapy; biologic subtype; radiation therapy technique, fractionation and boost; invasive lobular carcinoma or lobular carcinoma in situ; and young age. 

Developed in collaboration with:

  • American Society for Radiation Oncology
  • Society of Surgical Oncology

Endorsed by:

  • American Society of Breast Surgeons
  • American Society of Clinical Oncology

Key Points:

  • Risk of ipsilateral breast tumor recurrence (IBTR)
  • IBTR rate
  • Margin width
  • Local failure


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