Today we’re spotlighting the new American Society of Clinical Oncology (ASCO), American Society for Radiation Oncology (ASTRO), and Society of Surgical Oncology (SSO) clinical practice guidelines for postmastectomy radiation therapy (PMRT). This release is an update to the 2016 guideline, now featuring clarifying patient selection criteria and appropriate technical approaches for the delivery of PMRT, reflecting the evolving understanding of the benefit of PMRT. 

In this guideline release, there were four clinical key questions that were addressed: 

  1. What are the indications for PMRT in patients who receive mastectomy as their initial treatment for breast cancer? 
  2. What are the indications for PMRT in patients who receive neoadjuvant systemic therapy before mastectomy? 
  3. What are the appropriate treatment volumes (e.g., chest wall or reconstructed breast, regional nodes, boost) and dose-fractionation regimens for patients who receive PMRT? 
  4. What are the appropriate techniques (e.g., 3-dimensional conformal radiation therapy [3-D CRT], intensity-modulated radiation therapy [IMRT], protons, breath hold, bolus) for treating patients who receive PMRT?

For your convenience, we’ve highlighted key highlights below. 

Each section covers one of the four key questions, and includes the corresponding recommendations.

Key Elements of the 2025 Update:


Indications for PMRT With Mastectomy as Initial Treatment

The following recommendations have either a strong or conditional strength of recommendation. 

  1. For patients with node-positive (pN+) breast cancer, PMRT is recommended. (Strong)
  2. For patients with any pT4 breast cancer, PMRT is recommended even in the absence of any other risk factors. (Strong)
  3. For patients with pT3N0 breast cancer, PMRT is conditionally recommended. (Conditional)
  4. For patients with pT1-2N0 breast cancer, PMRT is not recommended. (Strong)
  5. For patients with positive surgical margins after mastectomy and no other indication for PMRT, RT to the chest wall/reconstructed breast alone is conditionally recommended. (Conditional)

Indications for PMRT With Neoadjuvant Systemic Therapy

The following recommendations have either a strong or conditional strength of recommendation.

  1. For patients with initial cT4 or cN2-3 breast cancer who receive neoadjuvant systemic therapy, PMRT is recommended regardless of pathologic response. (Strong)
  2. For patients with positive lymph nodes after neoadjuvant systemic therapy (ypN+), PMRT is recommended. (Strong)
  3. For patients with cT1-3N1 or cT3N0 breast cancer with pathologic negative nodes after neoadjuvant systemic therapy (ypN0), PMRT is conditionally recommended. (Conditional)
  4. For patients with cT1-2N0 breast cancer with pathologic negative nodes after neoadjuvant systemic therapy (ypN0), PMRT is not recommended. (Strong)
  5. For patients with positive surgical margins after neoadjuvant systemic therapy, PMRT is recommended. (Strong)

PMRT Treatment Volumes and Dose-Fractionation Regimens

The following recommendations have either a strong or conditional strength of recommendation.

  1. For patients receiving PMRT, treatment to the ipsilateral chest wall/reconstructed breast and regional lymphatics (ie, at-risk axillary nodes, supra/infraclavicular nodes, and IMNs) is recommended. (Strong)
  2. For patients without breast reconstruction receiving PMRT, moderate hypofractionation is recommended. (Strong)
  3. For patients with breast reconstruction receiving PMRT, moderate hypofractionation (preferred) or conventional fractionation is recommended. (Strong)
  4. For patients with T4 breast cancer or close/positive margins receiving PMRT, a boost to the chest wall/scar is conditionally recommended. (Conditional)
  5. For patients with nodal disease not surgically addressed and at risk of harboring residual disease, a nodal boost is recommended. (Strong)

Appropriate PMRT Delivery Techniques

The following recommendations have either a strong or conditional strength of recommendation.

  1. For patients receiving PMRT, CT-based volumetric treatment planning with 3-D CRT is recommended. (Strong)
  2. For patients receiving PMRT, IMRT (including VMAT) is recommended when 3-D CRT is unable to achieve treatment goals (ie, target coverage and normal tissue avoidance). (Strong)
  3. For patients receiving PMRT, DIBH is recommended when lower doses to normal tissues, including the heart and lungs, can be achieved compared with free breathing. (Strong)
  4. For patients receiving PMRT treated with IMRT (including VMAT), daily image guidance, in conjunction with regular 3-D assessments (eg, CBCT, SGRT), is recommended. (Strong)
  5. For patients with cT1-3 breast cancer receiving PMRT, the routine use of tissue-equivalent bolus is not recommended. (Strong)
  6. For patients with skin involvement, positive superficial margins, and those with dermal lymphatic involvement and/or extensive LVI, the use of tissue-equivalent bolus is recommended. (Strong)

For a more in-depth look at this guideline update, view our summary or view the full-text version.

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