Brian Lawenda, Radiation Oncologist at Advocate Radiation Oncology, shared a post on LinkedIn:
“You’ve seen the headlines for NSABP B-51: “Radiation no longer needed after neoadjuvant chemo!”
Not so fast.
The NSABP B-51 / RTOG 1304 trial is not a “no-radiation” study.
It’s a regional nodal irradiation (RNI) de-escalation trial, and its implications depend entirely on how you read the fine print.
The NEJM June 2025 NSABP B-51 / RTOG 1304 trial wasn’t a “skip-radiation” study.
It was a regional nodal irradiation (RNI) de-escalation trial – and its message is being misread.
Only a very small subset of patients qualify for radiation omission:
All five B-51 criteria must be met:
- Clinical T1–3, biopsy-proven cN1 (≤ 3 suspicious nodes on imaging)
- Biopsy-proven nodal disease before neoadjuvant chemotherapy
- Pathologically node-negative (ypN0) confirmed by ≥ 2 sentinel nodes or axillary dissection
- No extranodal extension (ENE) on final pathology (ENE before NAC acceptable)
- Targeted Axillary Dissection (TAD) strongly preferred to confirm clearance
Miss one – and the risk of locoregional recurrence jumps from ~1 % to 10–15 % without radiation.
My deep-dive analysis covers:
–What B-51 actually tested (and what it didn’t)
–The underpowered mastectomy arm (43 events; CI crosses 1.0)
–When to consider omission vs when to treat (WBRT, RNI, PMRT)
–2025 guideline alignment (NCCN, ASTRO–ASCO–SSO, EBCTCG)
–How to apply it in tumor board decisions safely
More posts featuring Brian Lawenda on OncoDaily.
You Can Also Read: New Paper Alert: NRG‑NSABP B‑51/RTOG 1304 Trial on Regional Nodal Irradiation Omission in ypN0 Breast Cancer After Neoadjuvant Chemotherapy
