A major study, NRG-NSABP B-51/RTOG 1304, published on June 4, 2025, in the New England Journal of Medicine, shows regional nodal irradiation (RNI) does not lower breast cancer recurrence. This applies to patients whose lymph nodes turn negative after chemotherapy. The study is changing breast cancer treatment, offering simpler, effective care.
Key Findings of the Breast Cancer Treatment Study
The study included 1,641 patients with node-positive breast cancer that became node-negative after chemo. Patients had either lumpectomy or mastectomy. Lumpectomy patients got radiation to the breast alone or with lymph nodes. Mastectomy patients received chest wall and lymph node radiation or none. The main measure, invasive breast cancer recurrence-free interval, showed no benefit from RNI (HR=0.88, 95% CI 0.60-1.28; p=0.51). Five-year recurrence-free rates were 91.8% without RNI and 92.7% with RNI.
Bruce G. Haffty, MD, a radiation oncologist at Rutgers Cancer Institute, said, “The number of events was very, very small and that the radiation to the regional lymph nodes really did not improve the patient’s outcome.” Many patients can skip regional radiation in their breast cancer treatment.
How This Changes Breast Cancer Treatment
The study has a big impact, as Bruce G. Haffty, MD noted: “It really changed the standard of care because up until this point patients originally had node positive disease and converted to node negative we would still treat them after mastectomy or after lumpectomy to the breast in the regional lymph nodes.” Now, lumpectomy patients may only need breast radiation. Some mastectomy patients can avoid radiation, cutting side effects while keeping recurrence risks low.
However, Bruce G. Haffty, MD warned, “The recurrence risk was low but it wasn’t zero. So what we tell patients is that they still need to be followed both for systemic therapy and for local regional recurrence.” Some patients, like those with estrogen receptor-positive and HER2-negative tumors, may still need radiation. This highlights custom breast cancer treatment plans.
Why This Matters for Breast Cancer Patients
Shared at the San Antonio Breast Cancer Symposium in December 2024, these results are already shaping breast cancer treatment. The full paper is still pending. “I think it is already changing practice,” said Bruce G. Haffty, MD. He stressed team discussions to personalize treatments. He added, “If they were node-positive and they responded well and converted to node-negative, the recurrence risk was very low and that’s good news for the patients.”
Another trial, led by Dr. Bowie of ASBRS, looks at axillary dissection versus radiation for patients with positive nodes after chemo. Results are not ready yet. This study guides node-negative converters in breast cancer treatment.
Explore the Full Breast Cancer Study
For more details, read the study: Mamounas EP, et al. N Engl J Med 2025;392:2113-2124; DOI:10.1056/NEJMoa2414859. Talk to your healthcare team about how this applies to your breast cancer treatment plan.
Related Links:
https://www.nrgoncology.org/Home/News/Post/results-of-nrg-nsabp-b-51-rtog-1304