Surgery and Radiation Both Scaled Back Together in Only a Fraction of Early Breast Cancer Cases

One of the most consequential shifts in modern breast cancer medicine has been the deliberate retreat from maximal treatment. For decades, women with small, hormone-driven tumors faced the same aggressive playbook: removal and examination of underarm lymph nodes, followed by weeks of radiation to the entire breast. Today, guided by a generation of randomized trials, oncologists increasingly tailor therapy to the biology of each tumor, sparing patients procedures and treatments whose benefits may not justify their harms. Yet a new national analysis reveals that when it comes to combining two of these de-escalation strategies at once, American clinicians remain strikingly cautious.

The study, published in Breast Cancer Research and Treatment, drew on the National Cancer Database, a hospital-based registry that captures roughly seventy percent of newly diagnosed cancers in the United States. Researchers led by Dylan S. Brokaw and Austin D. Williams of Fox Chase Cancer Center identified 316,324 women aged 50 to 69 who were diagnosed between 2012 and 2022 with early-stage, hormone receptor-positive, HER2-negative breast cancer and who underwent breast-conserving surgery as their first treatment. This tumor subtype is among the most favorable in oncology, and it is precisely the population in which both surgical and radiation de-escalation have been validated.

The two de-escalation strategies in question target different parts of the treatment pathway. The first is the omission of sentinel lymph node biopsy, the surgical sampling of the first lymph nodes to which breast cancer typically spreads. Although far less invasive than the full axillary dissections of the past, sentinel node biopsy still carries risks of lymphedema, chronic pain, and restricted shoulder movement. The second strategy is accelerated partial breast irradiation, or APBI, which concentrates radiation on the tumor bed rather than the whole breast, shortening treatment and reducing exposure of healthy tissue. Randomized trials, including the APBI-IMRT-Florence trial and NSABP B-39/RTOG 0413, have shown comparable cancer control to whole breast irradiation in appropriately selected patients.

What the researchers found was a striking asymmetry. Radiation de-escalation has been embraced: APBI use more than doubled over the study period, rising from about eight percent of patients in 2012 to 16.5 percent by 2022, with a particularly sharp jump after the 2016 update of the ASTRO guideline that expanded APBI recommendations beyond clinical trial settings. Surgical de-escalation, by contrast, barely moved. Sentinel node biopsy was omitted in only about two percent of patients overall, peaking at 2.6 percent in 2016 before dipping to 1.4 percent in 2019 and recovering only partially to 1.8 percent by 2022. Meanwhile, complete axillary dissection declined steadily from 16.4 percent to 4.2 percent, reflecting the earlier and more universally accepted transition from full nodal removal to sentinel sampling.

The central finding, however, concerned the combination of the two strategies. Dual de-escalation, defined as omitting sentinel node biopsy while delivering APBI, was performed in fewer than 0.30 percent of eligible patients in every single year of the eleven-year study. After a modest uptick beginning in 2018, the rate plateaued at roughly 0.23 to 0.26 percent. In other words, even among women whose tumors were small, low-grade, and hormone-driven, the overwhelming majority still underwent both node sampling and either whole breast irradiation or no radiation at all, but almost never the paired minimal approach.

The authors argue that this reluctance is not irrational. Omitting sentinel node biopsy eliminates pathological staging of the axilla, information that can influence decisions about systemic therapy. At the same time, replacing whole breast irradiation with APBI reduces the incidental radiation dose that reaches the low axilla, a dose that may otherwise suppress subclinical nodal disease. Combining the two could therefore create a staging and treatment gap: a patient with undetected nodal involvement receives neither the diagnostic procedure nor the comprehensive radiation field that might have addressed it. The degree to which whole breast irradiation actually treats the axilla varies with beam angle, field borders, and technique, but clinicians have historically viewed it as a partial safeguard, and removing that safeguard without knowing nodal status introduces uncertainty about locoregional control.

Importantly, the study period ended in 2022, before the publication of the trials that have since transformed this debate. The SOUND trial, reported in 2023, and the INSEMA trial, reported in 2025, both demonstrated that omitting sentinel node biopsy is non-inferior to performing it in clinically node-negative patients with small tumors and negative preoperative axillary ultrasound. The BOOG 2013-08 trial has added further support. The patterns documented in this analysis therefore represent a pre-trial baseline: a portrait of how cautiously clinicians behaved when extrapolating from older evidence, chiefly the CALGB 9343 trial and the 2016 Choosing Wisely recommendation, both of which applied only to women aged 70 and older.

The multivariable analysis revealed who was most likely to receive de-escalated care, and the patterns were consistent across all three outcomes. Small clinical T1 tumors, ductal rather than lobular histology, low tumor grade, and older age all predicted de-escalation, while larger, higher-grade, lobular tumors predicted adherence to standard treatment. Institutional factors mattered even more. Treatment at an academic or research program was associated with nearly twice the odds of sentinel node biopsy omission and more than twice the odds of dual de-escalation compared with community cancer centers, a difference the authors attribute to multidisciplinary tumor boards, clinical trial participation, and earlier familiarity with emerging data. Higher household income was also associated with combined de-escalation, echoing prior evidence that socioeconomic advantage facilitates access to complex treatment decisions. Notably, Black and Asian patients were significantly less likely than White patients to receive APBI, and uninsured patients were less likely to receive it than those with Medicare or private insurance, highlighting equity concerns in the diffusion of new techniques.

One further distinction emerged from the data: the difference between structured de-escalation and simple omission of therapy. Among patients whose sentinel node biopsy was skipped, thirty percent received no radiation at all, compared with just six percent of those who underwent node sampling. The authors suggest that the same vulnerable patients who benefit most from avoiding additional surgery may also struggle to complete multi-week radiation courses, whether because of patient preference, transportation barriers, or other unmeasured factors. Shortened, targeted regimens like APBI could offer these patients the benefit of adjuvant treatment without forcing an all-or-nothing choice, which makes the rarity of combined de-escalation all the more consequential.

The study has the limitations inherent to registry research: it cannot capture preoperative axillary imaging, adherence to hormone therapy, patient preferences, or the clinical reasoning behind each decision, and oncologic outcomes beyond survival were unavailable. Still, its message is clear. A small vanguard of clinicians, concentrated in academic centers, began pairing surgical and radiation de-escalation years before prospective evidence existed, while the broader oncology community waited. With the SOUND and INSEMA results now in hand, the question is no longer whether sentinel node biopsy can be omitted in selected patients, but whether the two de-escalations can be safely stacked. The authors call for prospective studies to define the safety, optimal patient selection, and quality-of-life outcomes of combined strategies, and their dataset provides the reference point against which any post-trial acceleration can be measured. Until those data arrive, they conclude, careful multidisciplinary evaluation and shared decision-making remain the essential safeguards for women with low-risk disease.

Subject of Research: Practice patterns in combined de-escalation of axillary surgery and adjuvant radiation for early-stage HR-positive/HER2-negative breast cancer

Article Title: National trends in dual de-escalation of axillary surgery and adjuvant radiation in early-stage HR+/HER2- breast cancer

Article References: Brokaw, D. S., Kozian, L., Chang, C., Shulman, R. M., Bleicher, R. J., So, A., Aggon, A. A., & Williams, A. D. (2026). National trends in dual de-escalation of axillary surgery and adjuvant radiation in early-stage HR+/HER2- breast cancer. Breast Cancer Research and Treatment, 220(1), Article 6. https://doi.org/10.1007/s10549-026-08106-0

Image Credits: AI Generated

DOI: 10.1007/s10549-026-08106-0

Keywords: breast cancer, de-escalation, sentinel lymph node biopsy, accelerated partial breast irradiation, axillary surgery, radiation oncology, National Cancer Database, HR-positive HER2-negative, breast-conserving surgery, SOUND trial, INSEMA trial, surgical oncology