Omitting axillary dissection in patients with 1-2 sentinel node–positive breast cancer undergoing mastectomy in China: A retrospective cohort study with target trial emulation.

• DOI: 10.1200/jco.2025.43.16_suppl.e12577
• Publication Date: 2025-05-28T15:57:16Z
• Authors: Haitong Xie; Xin Wang; Xianlin Gu; Jie Chen
• Keywords: Axillary Dissection

e12577 Background: Trials have demonstrated the safety of omitting axillary dissection in patients with cT1-3, cN0, or iN0 breast cancer, and 1-2 sentinel-node involvement, who underwent breast-conserving surgery (BCS). Given limited data on mastectomy similar studies China, uncertain impact radiotherapy these outcomes, we aim to investigate whether is non-inferior performing it one more macrometastatic sentinel nodes undergoing China. Methods: We retrospectively emulated a target multicenter, non-blinded, noninferiority trial assess sentinel-lymph-node biopsy only (SLNB only) completion axillary-lymph-node (ALND) from medical database between 2014 2022, prospectively conducted randomized, 2022 2024. Patients were eligible if they had clinically node-negative primary T1-3 macrometastases. Adjuvant treatment radiation therapy used accordance national guidelines. The endpoint was recurrence-free survival (RFS), second overall (OS). Non-inferiority defined as hazard ratio (HR) less than 1.46 for no versus dissection. This registered Chictr.org.cn , ChiCTR2300072140. Results: A total 1,090 enrolled across seven centers. Of these, 438 (40.2%) assigned SLNB-only group, 652 (59.8%) ALND group. After median follow-up 44.7 months, 79 experienced recurrence death. estimated 5-year rate 89.8% (95% confidence interval [CI], 85.6%–94.2%) group 90.8% CI, 88.2%–93.6%) death 0.91 0.57–1.45). result significantly below pre-specified non-inferiority margin (P < 0.001). analysis remained consistent key subgroups sensitivity analyses. SLNB compared included 1.00 all subgroups. Radiotherapy (78.5% vs. 58.7%) chemotherapy (96% 93.2%) administered frequently Conclusions: In invasive cancer 1–2 macrometastases, omission terms survival. Clinical information: ChiCTR2300072140 .