Inflammatory Breast Cancer: Durable Breast Cancer-Specific Survival for HER2-Positive Patients with a Pathologic Complete Response to Neoadjuvant Therapy

Clipped Axillary Node as a Potential Surrogate for Overall Axillary Nodal Status in Inflammatory Breast Cancer Patients after Neoadjuvant Chemotherapy

BACKGROUND

Axillary lymph node dissection is the current standard for management of the axilla in inflammatory breast cancer (IBC). The present study aims to determine whether the initially positive node identified by clip placement accurately represents the overall nodal status of axilla after neoadjuvant chemotherapy (NAC) in IBC.

PATIENTS AND METHODS

A retrospective study was conducted on patients with IBC who underwent operation (2014-2023). For patients with IBC who had clip placement in a positive axillary node at diagnosis, operative notes, specimen radiographs, and pathology reports were reviewed to confirm final pathologic status of clipped nodes.

RESULTS

In total, 92 patients with IBC (90 cN+) were identified (median age 54 years, 78% invasive ductal, 10% invasive lobular, and 12% mixed); 81 (90%) were biopsy-proven cN+, with a clip placed in the positive node for 62/81 (77%). All patients were treated with NAC and axillary surgery with median 19 (range 4-49) nodes removed. Among 28 (out of 56) patients with retrieved clipped nodes that were pathologically negative (ypN0), only 1 had an additional positive node with micrometastasis for a false negative rate of 4% (95% CI 1-19%). Conversely, 3/3 patients with isolated tumor cells (ITCs) only in the clipped node had additional axillary disease (ITCs in 1, macrometastasis in 2), and 20/23 (87%) of patients with pathologically positive clipped node (micrometastasis or greater) had additional positive nodes [19/20 (95%) with macrometastasis].

CONCLUSIONS

The clipped biopsy-positive axillary node in IBC accurately represented the post-NAC overall axillary nodal status. ITCs post-NAC should be considered positive as an indicator of additional nodes with metastasis.

Advances from targeted therapy for non-metastatic HER2-positive inflammatory breast cancer

Among inflammatory breast cancer (IBC) patients, over one-third have HER2-overexpressing (HER2+) tumors. Pathologic complete response (pCR) rates to neoadjuvant targeted and chemotherapy for patients with HER2+ non-metastatic IBC now apporach 60% and favorable long-term survival rates are being reported for those with a pCR. Immune mechanisms contributing to this phenomenon include antibody-mediated immune activation and induction of memory T-cell reponses which may explain the sustained antitumor response seen after discontinuation of targeted therapies.

Comprehensive Characterization of Immune Cell Infiltration Characteristics and Drug Sensitivity Analysis in Inflammatory Breast Cancer Based on Bioinformatic Strategy

Inflammatory breast cancer (IBC) is a rare and highly invasive form of breast cancer, renowned for its aggressive behavior, malignant capacity, and unfavorable prognosis. Despite considerable advancements in comprehending the underlying biology of IBC, the immune cell infiltration (ICI) profile in IBC remains inadequately elucidated. The current work endeavors to investigate the ICI characteristics of IBC and ascertain the pivotal immune cell subtypes and genes that impact its prognosis. The present study employed microarray data from the GEO database to demonstrate that IBC exhibited a lower abundance of activated mast cells (AMC) in comparison to non-inflammatory breast cancer (nIBC) or normal breast tissue (NBT). Additionally, the mRNA expression level of the gene polo-like kinase 5 (PLK5), which was correlated with AMC, was found to be lower in IBC relative to nIBC or NBT. Furthermore, this investigation provided compelling evidence indicating a potential association between a decreased mRNA expression level of PLK5 and a shorter progression-free survival in patients with breast cancer. The gene set enrichment analysis performed on PLK5 revealed that the gene expression in IBC was closely associated with diverse immune functions and pathways. Besides, a negative correlation has been established between PLK5 mRNA expression level and a majority of immune checkpoint-related genes, thereby suggesting the potential suitability of immunotherapy treatment for IBC. In summary, this study offers valuable insights into the ICI profile of IBC and identifies potential target PLK5 for improving its clinical management.