Reevaluating sentinel lymph node biopsy in older adults with T1 HR+/HER2- breast cancer: a SEER competing risk and
Ziqiang Wang1, Yangyang Xie2, Weijun Zhang1
1The First People's Hospital of Xiaoshan District, Xiaoshan Affiliated Hospital of Wenzhou Medical University, Hangzhou, 311000, China.
Background:
Sentinel lymph node biopsy (SLNB) is the standard procedure for axillary staging. However, its necessity in older patients (≥ 70 years) with HR+/HER2- T1 breast cancer remains debated in the context of contemporary de-escalation strategies. Existing evidence often incompletely accounts for the competing risk of death in this population. We evaluated the association between SLNB and breast cancer-specific death (BCSD) using real-world data.
Methods:
Women aged ≥ 70 years with HR+/HER2- T1 (≤ 20 mm) breast cancer treated with breast-conserving surgery between 2010 and 2021 were identified from the SEER database and classified into SLNB and No-SLNB groups. Propensity score matching (PSM) and Fine-Gray competing risk models were used to estimate subdistribution hazard ratios (sHRs) for BCSD and other-cause death (OCD). A prognostic nomogram was constructed.
Results:
Among 47,838 eligible patients, 37,732 underwent SLNB and 10,106 did not. After PSM, SLNB was associated with a lower 5-year cumulative incidence of BCSD (2.50% vs. 3.50%); differences in OCD were also observed. In multivariable competing risk analysis, SLNB remained independently associated with reduced BCSD (sHR 0.69, 95% CI 0.60-0.80). The association was most pronounced in patients aged ≥ 80 years and those with T1c (11-20 mm) tumors, whereas the absolute risk difference was minimal in the 1-5 mm subgroup. The nomogram showed good discrimination (time-dependent AUC up to 0.821 in the training set and 0.857 in the validation set) and calibration.
Conclusions:
In this real-world cohort, SLNB was associated with lower BCSD in older adults with HR+/HER2- T1 breast cancer, particularly in those aged ≥ 80 years or with T1c tumors. While the incremental value of SLNB appears limited in ultra-low-risk groups, age alone should not dictate omission of axillary staging. The nomogram may support individualized decision-making.
