Patient Care and Research

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:‚Äč

  • 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


Breast Cancer Refresher - 2017 (CME)
Timing of RT and Chemo after BCS for Node-Positive Breast Cancer (CME)
Patient Brochure

We have recently updated our privacy policy and terms of use.
By using this site, you agree to ASTRO’s Privacy Policy and Terms of Use.
We use cookies to provide, secure and improve our services to you. To learn more, click here.