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.