Higher axillary lymph node metastasis burden in breast cancer patients with positive preoperative node biopsy: may not be appropriate to receive sentinel lymph node biopsy in the post-ACOSOG Z0011 trial era

Background Breast cancer patients with suspicious axillary lymph node (ALN) at ultrasound and positive fine-needle aspiration (FNA) results were required to receive ALN dissection (ALND), which was not certain in the post-ACOSOG Z0011 era. We aim to evaluate the ALN metastasis burden in these patients, thus to illustrate whether they can follow the ACOSOG Z0011 trial procedure. Methods Clinically, T1–2 N0 breast cancer patients with positive preoperative ALN biopsy (FNA group) or 1–2 positive sentinel nodes (SLNB group) were retrospectively analyzed. ALN metastasis burden was compared between the two groups, which were further analyzed in certain subtypes. An association between clinicopathological factors and ≥ 3 ALN metastasis was also analyzed. Results A total of 388 patients were included: 202 in the FNA group and 186 in the SLNB group. The FNA group had a significantly higher number of positive ALN (5.18 vs. 1.77, P < 0.001) and a larger proportion of patients with ≥ 3 ALN metastasis (58.42% vs. 11.83%, P < 0.001) than the SLNB group, which was not influenced by different tumor size stage and molecular subtypes. ALN metastasis identified by FNA was independently associated with a high rate of ≥ 3 ALN metastasis (OR = 6.98, 95% CI 1.95–25.02, P = 0.003). Conclusions Patients with positive preoperative ALN biopsy had a higher ALN metastasis burden than patients with 1–2 positive SLNs, which was also the strongest factor associated with ≥ 3 ALN metastasis, indicating that these patients are not appropriate to receive SLNB in the post-ACOSOG Z0011 trial era.