Omission of Axillary Lymph Node Dissection in Patients with pT0-2 ER+/HER2- Breast Cancer with 3-5 Positive Lymph Nodes Undergoing Adjuvant Systemic Therapy and Radiation Does Not Impact Overall Survival: A National Cancer Database Analysis.

BACKGROUND

Recent trials established safety of axillary lymph node dissection (ALND) omission in patients with 1-2 positive lymph nodes (LN) on sentinel LN biopsy (SLNB). However, the benefit of ALND in patients with 3-5 positive LNs remains debated. We examined national trends of ALND versus SLNB in this subgroup and evaluated survival outcomes.

PATIENTS AND

METHODS

Using the National Cancer Database, we identified patients with pT0-2 ER+/HER2- breast cancer with 3-5 positive LNs who underwent adjuvant chemotherapy, endocrine therapy, and radiation therapy from January 2012 to December 2020. We compared patients who had SLNB alone versus ALND ± SLNB

RESULTS

Among 13,270 patients, 1712 (12.9%) had SLNB and 11,558 (87.1%) had ALND. ALND rates decreased by 18.3% during the study period (93.4% to 75.1%). Compared with ALND, SLNB group had higher proportion of three positive LNs (63.1% versus 43.1%, p < 0.001), Charlson Comorbidity Index 0 (87.4% versus 84.4%, p = 0.001), pT1 tumor (42.8% versus 35.4%, p < 0.001), well-to-moderately differentiated tumor (72% versus 66.9%, p < 0.001), absence of lymphovascular invasion (42.7% versus 36.3%, p < 0.001), and lobular histology (16.5% versus 12.7%, p < 0.001). There was no difference in overall survival (OS) between SLNB and ALND in univariate or multivariable models (adjusted HR 1.0, p = 0.77).

CONCLUSIONS

National rates for ALND decreased in patients with 3-5 positive LNs over the last decade. There was no difference in OS with omission of ALND in patients with ER+/HER2- breast cancer with 3-5 positive LNs, supporting further studies to evaluate deescalation of axillary surgery in this population.