Axillary Pathologic Complete Response in Inflammatory Breast Cancer Patients: Implications for SLNB?

Sentinel lymph node biopsy (SLNB) is increasingly utilized after neoadjuvant chemotherapy (NAC) in responsive adenopathy, particularly with placement of a marking clip in the involved node(s). This may allow a subset of patients to avoid axillary lymph node dissection. SLNB is still discouraged in inflammatory breast cancer (IBC). The purpose of this study is to examine the axillary pathologic complete response (AXpCR) in IBC patients with clinical adenopathy. There may be an implication to approach a subset of IBC patients for SLNB after NAC.

A single-institution institutional review board-approved database was reviewed. Inclusion criteria were clinicopathologic diagnosis of IBC and age ≥ 18 years. Stage IV disease was excluded. We collected data on demographics, tumor characteristics including histology and subtype, axillary status, and treatment effect details.

Sixty-six patients fulfilled criteria. Mean follow-up was 4.1 years. The AXpCR was 6% for luminal A and luminal B [human epidermal growth factor receptor (HER)2 -] subtypes, and 24% for basal subtype. The AXpCR rate was 64% for HER2-enriched and luminal B (HER2 +) patients. Achievement of AXpCR among these HER2-positive patients was statistically significant (p = 0.0001). There was minimal difference in achieving AXpCR in HER2-overexpressing patients regardless of hormone receptor status (p = 1.000).

Understanding the best patients to select for use of SLNB or targeted lymph node dissection after treatment is evolving. This unique series identified and described the axillary pathologic characteristics of IBC patients following NAC. Further research is needed to confirm that the approach, axillary node clip placement prior to treatment, is feasible and accurate in IBC.