Inflammatory Breast Cancer: A Distinct Clinicopathological Entity Transcending Histological Distinction

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.

Inflammatory breast cancer: An overview about the histo-pathological aspect and diagnosis

Inflammatory Breast Cancer (IBC) is a rare and aggressive form of locally advanced breast cancer, classified as stage T4d according to the tumor-node-metastasis staging criteria. This subtype of breast cancer is known for its rapid progression and significantly lower survival rates compared to other forms of breast cancer. Despite its distinctive clinical features outlined by the World Health Organization, the histopathological characteristics of IBC remain not fully elucidated, presenting challenges in its diagnosis and treatment. Histologically, IBC tumors often exhibit a ductal phenotype, characterized by emboli composed of pleomorphic cells with a high nuclear grade. These emboli are predominantly found in the papillary and reticular dermis of the skin overlaying the breast, suggesting a primary involvement of the lymphatic vessels. The tumor microenvironment in IBC is a complex network involving various cells such as macrophages, monocytes, and predominantly T CD8+ lymphocytes, and elements including blood vessels and extracellular matrix molecules, which play a pivotal role in the aggressive nature of IBC. A significant aspect of IBC is the frequent loss of expression of hormone receptors like estrogen and progesterone receptors, a phenomenon that is still under active investigation. Moreover, the overexpression of ERBB2/HER2 and TP53 in IBC cases is a topic of ongoing debate, with studies indicating a higher prevalence in IBC compared to non-inflammatory breast cancer. This overview seeks to provide a comprehensive understanding of the histopathological features and diagnostic approaches to IBC, emphasizing the critical areas that require further research.

Inflammatory breast cancer: Epidemiologic data and therapeutic results

Since the early description more than a century ago, inflammatory breast cancer (IBC) remains an aggressive disease, with a different geographic repartition, with the highest ones incidence reported in the North of Africa (Tunisia, Algeria, Morocco, and Egypt), and the lowest incidence in Western countries (USA, Europe…). In this study, we reviewed the literature using the Surveillance, Epidemiology, and End Results (SEER) database compared to other published series. We observed that in the high incidence areas (North of Africa) when compared to "classical" breast cancer, IBC was associated to younger age (less than 50 years) with rapid evolution of signs and symptoms (in less than 3 up to 6 months), and more aggressive clinical and histopathological-molecular parameters, due to the predominance of triple-negative and HER2+ subtypes in around 60% of cases. An epidemiologic trend was observed in both high and low incidence areas since the eighties are towards reduction of IBC prevalence. Concerning Tunisia, in comparison with the historical series of the 1980s, the incidence decreased in part by applying more stringent diagnostic criteria but also probably due to a slight improvement of the socio-economic level (SEL). This trend was also observed in the US, due to the efforts of collaborative IBC groups from MD Anderson Cancer Center (MDACC), Duke and IBC patient advocacy groups. Therapeutic results are slightly better due to the standardization of a multidisciplinary approach and the use of combined primary chemotherapy and/or targeted therapies (especially in HER2 positive patients), followed by mastectomy plus radiotherapy. The 5-year overall and disease-free survival is at more than 60%, related to an IBC mortality decrease observed in the cohorts of patients treated in the last decade.

Systematic Review and Meta-Analysis of Treatment Effects on Survival in Patients with Inflammatory Breast Cancer

The objective of this study was to determine the survival rate and the effects of different treatments on patients with inflammatory breast cancer (IBC). The study employed a systematic approach that included a search strategy across four databases: Embase, Web of Sciences, PubMed, and Scopus. The results obtained were screened initially by titles and abstracts, followed by full-texts in EndNote 8 software. The next stage involved data extraction and qualitative evaluation, where the Metan command was used to estimate the pooled survival rate. A total of 28 studies with a sample size of 63,796 were finally analyzed. The overall 3- and 5-year survival rates (OS) for IBC patients were found to be 52% (95% CI; 46-58%, I2: 99.42%) and 61% (95% CI; 53-69%, I2: 93.63%), respectively. The 5-year OS rates in patients with non-metastatic and metastatic IBC were 59% (95% CI; 54-63%, I2: 98.31%) and 30% (95% CI; 26-35%, I2: 50.84%), respectively. The 5-year OS rate in non-metastatic patients who underwent BCS surgery was 60% (CI 95%; 26-94%, I2: 95.13%). The overall 5- and 3-year OS rates for patients with IBC were lower than those for all types of breast cancer, and the rates were even lower in patients with metastasis. Therefore, it is recommended that healthcare workers and women at risk should be vigilant of early symptoms of IBC to prevent metastasis by seeking medical attention on time.

Mammographically Occult Invasive Lobular Carcinoma With Intradermal Invasion

While shortcomings in the detection of invasive lobular carcinoma (ILC) continue to be studied, research is ongoing to determine detection rates using current breast imaging modalities in combination with physical examination findings. In the following case report, we describe the rare presentation of a patient diagnosed by punch biopsy with grade III, estrogen receptor (ER)-/progesterone receptor (PR)-positive invasive lobular carcinoma with intradermal invasion. This patient presented with findings similar to inflammatory breast cancer (IBC) including pain in the left nipple, skin warmth, and erythema circumferentially encompassing approximately two-thirds of the left breast. This case study is of significance as, to date, it is the first report of an invasive lobular carcinoma that presented clinically as inflammatory breast cancer and was occult on both diagnostic mammography and ultrasound. While imaging remains the primary method of breast cancer detection, it is important to note that clinical findings of dermal invasion of the breast may prompt further investigation with a biopsy and close follow-up, regardless of imaging results.

Forecasting factors and outcomes in hawkish inflammatory breast carcinoma - A single center data exploration

INTRODUCTION

Inflammatory breast carcinoma (IBC) is an aggressive clinical syndrome of invasive breast carcinoma. There is paucity of data regarding the outcomes in IBC.

OBJECTIVES

Analyses of OS and Event-free survival (EFS) in nonmetastatic and metastatic IBC and to find prognostic factors influencing them.

METHODOLOGY

In this single center, retrospective study the data of patients fulfilling the clinical criteria of IBC were retrieved from 2016 to 2021. The impact of prognostic factors on OS and EFS were analysed by log rank test (univariate analysis). The OS and EFS were depicted as Kaplan Meier survival curves.

RESULTS

There were 22 patients with IBC. Median follow-up was 17 months. The median OS was significantly better in non-metastatic(M0) compared to metastatic IBC (25 months vs 6 months) with 3year OS rate of 50% vs 0% respectively. The post-menopausal status, grade 2 histology and trimodality treatment showed better outcome while N3 stage at diagnosis had worse outcome in M0 group. The lesser HR expression, lesser pCR rates, higher N3 proportion, liver metastasis and multiple metastatic site involvement contributed to the worse outcome observed in this study.

CONCLUSION

The aggressive clinicopathological features of IBC in the present study resulted in less favourable outcome compared to literature review. Improved outcome with trimodality highlights the emergent need for additional targeted therapy to improve pCR and operability.

Inflammatory breast cancer with excellent response to pembrolizumab-chemotherapy combination: A case report

Inflammatory breast cancer (IBC) is a rare variety of breast cancer accounting for two percent of breast cancer diagnoses in the United States. It is characterized by peau d'orange, breast edema and erythema on physical examination and dermal lymphatic invasion by tumor emboli on histological examination. Micrometastases to lymphatics and bone marrow at the time of diagnosis and angiogenic properties of IBC explain the high propensity of this cancer to relapse and metastasize, its aggressiveness and poor prognosis. Preoperative sequential anthracycline and taxane (plus trastuzumab and pertuzumab if HER2-positive) based chemotherapy is the current standard of care for IBC. We herein report a case of stage IIIC triple-negative IBC treated with pembrolizumab plus chemotherapy based neoadjuvant therapy with a complete clinical and complete pathological response. This is the first case of triple-negative IBC treated with this regimen reported in the literature, thereby providing clinical data on the tolerability and efficacy of pembrolizumab plus chemotherapy based neoadjuvant regimen for the treatment of IBC.

Radiotherapy in the Management of Non-Metastatic Inflammatory Breast Cancers: A Retrospective Observational Study

(1) Background: Inflammatory breast cancers (IBC) are characterized by a poor prognosis. This retrospective study aims to describe the clinical outcomes of non-metastatic IBC patients treated with a multidisciplinary approach with neo-adjuvant chemotherapy, surgery, and radiotherapy. (2) Methods: This single-center retrospective study included all women patients diagnosed with non-metastatic IBC between January 2010 and January 2018 at the Institut Curie (Paris, France) and treated with neoadjuvant chemotherapy, surgery, and radiotherapy. Overall survival (OS), disease-free survival (DFS), and locoregional free survival (LRRFS) were calculated from the time of diagnosis. Prognostic factors for patient survival were analyzed based on univariate and multivariate regressions. (3) Results: We identified 113 patients with a median age of 51 years. 79.7% had node-positive tumors; triple-negative breast cancers (TNBC) represented 34.6% of the cases. A large majority of patients (91.2%) received adjuvant post-mastectomy while ten patients (8.8%) received preoperative radiotherapy. Non-pathological complete response (non-pCR) was observed in 67.3% of patients. Radiotherapy delivered a median dose of 50 Gy to the breast or the chest wall in 25 fractions. With a median follow-up of 54 months, 5-year OS, DFS and LRRFS were 78% (CI: 70.1-86.8%), 68.1% (59.6-77.7%), and 85.2% (78.4-92.7%), respectively. In multivariate analysis, non-pCR was an adverse prognosis factor for OS, DFS, and LRRFS; pre-operative radiotherapy was an adverse prognosis factor for OS and DFS. Radiation-related adverse events were limited to acute skin toxicity (22% of Grade 2 and 2% of grade 3 dermatitis); no late radiation-induced toxicity was reported. (4) Conclusions: High locoregional control could be achieved with multidisciplinary management of non-metastatic IBC, suggesting the anti-tumor efficacy of radiotherapy in this rare but pejorative clinicopathological presentation. While comparing favorably with historical cohorts, OS and DFS could be potentially improved in the future with the use of new systemic treatments, such as PARP-inhibitors or immunotherapy.

Inflammatory breast cancer: early recognition and diagnosis is critical

Inflammatory breast cancer is a rare and aggressive malignancy that is often initially misdiagnosed because of its similar presentation to more benign breast pathologies such as mastitis, resulting in treatment delays. Presenting symptoms of inflammatory breast cancer include erythema, skin changes such as peau d' orange or nipple inversion, edema, and warmth of the affected breast. The average age at diagnosis is younger than in noninflammatory breast cancer cases. Known risk factors include African American race and obesity. Diagnostic criteria include erythema occupying at least one-third of the breast, edema, peau d' orange, and/or warmth, with or without an underlying mass; a rapid onset of <3 months; and pathologic confirmation of invasive carcinoma. Treatment of inflammatory breast cancer includes trimodal therapy with chemotherapy, surgery, and radiation. An aggressive surgical approach that includes a modified radical mastectomy enhances survival outcomes. Although the outcomes for patients with inflammatory breast cancer are poor compared with those of patients with noninflammatory breast cancer, patients with inflammatory breast cancer who complete trimodal therapy have a favorable locoregional control rate, underscoring the importance of a prompt diagnosis of this serious but treatable disease. Obstetrician-gynecologists and other primary care providers must recognize the signs and symptoms of inflammatory breast cancer to make a timely diagnosis and referral for specialized care.

Recent advances in the epidemiology of inflammatory breast cancer

The survival after the diagnosis of inflammatory breast cancer (IBC) has been steadily improving for the past few decades. This has been due to advances in the knowledge of IBC in a number of fields, including epidemiology, molecular biology, and medical management. In this review we summarize some of the most important recent advances in these fields and suggest possible opportunities for continued improvement.

Magnetic resonance imaging in the evaluation of pathologic nipple discharge: indications and imaging findings

Pathologic nipple discharge (PND) is typically unilateral, spontaneous, involves a single duct, and is serous or bloody in appearance. In patients with PND, breast MRI can be helpful as an additional diagnostic tool when conventional imaging with mammogram and ultrasound are negative. MRI is able to detect the etiology of nipple discharge in 56-61% of cases when initial imaging with mammogram and ultrasound are negative. Advantages to using MRI in evaluation of PND include good visualization of the retroareolar breast and better evaluation of posterior lesions which may not be well evaluated on mammograms and galactograms. It is also less invasive compared to central duct excision. Papillomas and nipple adenomas are benign breast masses that can cause PND and are well visualized on MRI. Ductal ectasia, and infectious etiologies such as mastitis, abscess, and fistulas are additional benign causes of PND that are well evaluated with MRI. MRI is also excellent for evaluation of malignant causes of PND including Paget's disease, ductal carcinoma in-situ and invasive carcinoma. MRI's high negative predictive value of 87-98.2% is helpful in excluding malignant etiologies of PND.

Erythema of the skin after breast radiotherapy: It is not always recurrence

Recurrence of breast cancer is a predominant fear for patients who were treated for breast cancer. Acute and late dermatologic effects of radiotherapy are not uncommon and could have similar characteristics to breast cancer recurrence. Thus, it is important to highlight key differences between the clinical and histologic presentations of radiation effects and recurrence. Herein, we present two patients who presented with late dermatologic effects of radiotherapy months to years after treatment, neither of whom had workup consistent with cancer recurrence. We provide clinical and microscopic descriptions of each case and provide a review to differentiate various dermatologic conditions. This report aims to outline potential late dermatologic effects of radiation treatment and emphasise that changes in the breast do not always signal breast cancer recurrence.

Biological subtype, treatment response and outcomes in inflammatory breast cancer using data from the National Cancer Database

BACKGROUND

Although inflammatory breast cancer (IBC) is postulated to be a distinct biological entity, practice guidelines and previous data suggest that treatment and outcomes are influenced by standard approximated biological subtype. The aim of this study was validation in a large recent National Cancer Database (NCDB) patient cohort.

METHODS

Patients with non-metastatic IBC treated in 2010-2015 with neoadjuvant systemic therapy and surgery were identified from the NCDB. Approximated biological subtypes were categorized as oestrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-), ER-/HER2- and HER2+. Total pathological complete response (pCR) was defined as ypT0/ypTis, ypN0. χ² tests were used to compare pCR rates, and Kaplan-Meier curves and Cox proportional hazards regression to analyse overall survival.

RESULTS

Among 4068 patients with IBC (median age 56 years), the approximated biological subtype was ER+/HER2- in 1575 (38·7 per cent), HER2+ in 1323 (32·5 per cent) and ER-/HER2- in 1170 (28·8 per cent). A total of 3351 patients (84·0 per cent) were cN+ at presentation, with no differences across subtypes. Total pCR rates varied significantly by subtype: ER+/HER2- (6·2 per cent), HER2+ (38·8 per cent), ER-/HER2- (19·1 per cent) (P < 0·001), as did breast pCR rates (10·4, 44·5 and 25·2 per cent respectively) and nodal pCR rates (16·9, 56·9 and 33·1 per cent). The 5-year overall survival rate varied significantly across subtypes (ER+/HER2- 64·9 per cent, HER2+ 74·0 per cent, ER-/HER2- 44·0 per cent; P < 0·001) and by pCR within subtypes (all P < 0·001). In multivariable analysis, ER-/HER2- subtype (hazard ratio 2·89 versus HER2+ as reference; P < 0·001) and absence of total pCR (hazard ratio 3·23; P < 0·001) predicted worse survival.

CONCLUSION

Both treatment response and survival in patients with IBC varied with approximated biological subtype, as among other invasive breast cancers. These data support continued tailoring of systemic treatment to approximated biological subtype and highlight the recent improved outcomes in patients with HER2+ disease.

Inflammatory breast cancer: no longer an absolute contraindication for breast conservation surgery following good response to neoadjuvant therapy

Inflammatory breast cancer (IBC) is a rare form of breast cancer characterised by an erythematous swollen breast with extensive oedema and has in the past been associated with a very poor prognosis. After diagnosis by core biopsy of the cancer and any involved nodes patients in the Edinburgh Breast Unit (EBU) are primarily managed with neoadjuvant systemic therapy-chemotherapy or endocrine therapy. If the cancer is localised to one or a few well defined lesions then each of these lesions together with the lowest involved node are clipped. Response during neoadjuvant treatment is monitored clinically and by ultrasound plus mammography +/- magnetic resonance imaging (MRI). Following completion of neoadjuvant therapy, imaging is reviewed at a multidisciplinary meeting and patients with a localised single or multiple areas of cancer where all signs of erythema and oedema have settled are considered as to their suitability for breast conserving surgery and whole breast radiotherapy [breast conserving treatment (BCT)]. Here we discuss the results and outcomes of a selected group of patients with IBC who after obtaining a very good response to neoadjuvant chemotherapy or endocrine therapy were treated by BCT and we compare these with other recent publications on this topic. Our data show that patients treated by BCT did not have worse outcomes than patients treated with mastectomy. Importantly other series published recently support our conclusions. Another important observation is that response in estrogen receptor (ER) rich IBC is seen with neoadjuvant endocrine treatment and so not everyone with IBC needs to have neoadjuvant chemotherapy. In conclusion, patients with one or more well defined and localised breast masses and IBC may be suitable for BCT after a major response to neoadjuvant therapy and for these patients BCT should now be considered a viable option.

The presentation, management and outcome of inflammatory breast cancer cases in the UK: Data from a multi-centre retrospective review

OBJECTIVES

Inflammatory Breast cancer (IBC) is a rare but aggressive form of breast cancer. Its incidence and behaviour in the UK is poorly characterised. We collected retrospective data from hospitals in the UK and Ireland to describe the presentation, pathology, treatment and clinical course of IBC in the UK.

MATERIALS AND METHODS

Patients with IBC diagnosed between 1997-2014 at fourteen UK and Irish hospitals were identified from local breast unit databases. Patient characteristics, tumour pathology and stage, and details of surgical, systemic and radiotherapy treatment and follow-up data were collected from electronic patient records and medical notes.

RESULT

This retrospective review identified 445 patients with IBC accounting for 0.4-1.8% of invasive breast cancer cases. Median follow-up was 4.2 years. 53.2% of tumours were grade 3, 56.2% were oestrogen receptor positive, 31.3% were HER2 positive and 25.1% were triple negative. 20.7% of patients had distant metastases at presentation. Despite trimodality treatment in 86.4%, 40.1% of stage III patients developed distant metastases. Five-year overall survival (OS) was 61.0% for stage III and 21.4% for stage IV patients.

CONCLUSIONS

This is the largest series of UK IBC patients reported to date. It indicates a lower incidence than in American series, but confirms that IBC has a high risk of recurrence with poor survival despite contemporary multi-modality therapy. A national strategy is required to facilitate translational research into this aggressive disease.

Inflammatory Breast Cancer: What to Know About This Unique, Aggressive Breast Cancer

Inflammatory breast cancer (IBC) is a rare form of breast cancer that accounts for only 2% to 4% of all breast cancer cases. Despite its low incidence, IBC contributes to 7% to 10% of breast cancer caused mortality. Despite ongoing international efforts to formulate better diagnosis, treatment, and research, the survival of patients with IBC has not been significantly improved, and there are no therapeutic agents that specifically target IBC to date. The authors present a comprehensive overview that aims to assess the present and new management strategies of IBC.

International Consensus on the Clinical Management of Inflammatory Breast Cancer from the Morgan Welch Inflammatory Breast Cancer Research Program 10th Anniversary Conference

National and international experts in inflammatory breast cancer (IBC) from high-volume centers treating IBC recently convened at the 10th Anniversary Conference of the Morgan Welch Inflammatory Breast Cancer Research Program at The University of Texas MD Anderson Cancer Center in Houston Texas. A consensus on the clinical management of patients with IBC was discussed, summarized, and subsequently reviewed. All participants at the conference (patients, advocates, researchers, trainees, and clinicians) were queried using the MDRing electronic survey on key management issues. A summary of the expert consensus and participant voting is presented. Bilateral breast and nodal evaluation, breast magnetic resonance imaging, positron emission tomography/computed tomography, and medical photographs were endorsed as optimal. Neoadjuvant systemic therapy, modified radical mastectomy and level I and II ipsilateral axillary node dissection, post-mastectomy radiotherapy, adjuvant targeted therapy and hormonal therapy as indicated, and delayed reconstruction were agreed-upon fundamental premises of standard non-protocol-based treatment for IBC. Consideration for local-regional therapy in de novo stage IV IBC was endorsed to provide local control whenever feasible. Variation across centers and special circumstances were discussed.

Development of CNS metastases and survival in patients with inflammatory breast cancer

BACKGROUND

Inflammatory breast cancer (IBC) is associated with a poor prognosis and high risk of central nervous system (CNS) metastases.

METHODS

We retrospectively reviewed stage III-IBC patients compared with noninflammatory invasive ductal carcinoma (NI-IDC) patients treated between January 1, 1984, and December 31, 2011, who began primary treatment within 1 year of diagnosis and had been followed up for at least 1 year before the development of CNS metastasis or death. Cumulative CNS metastasis incidence and post-CNS metastasis overall survival (OS) estimates were computed. Multivariable Cox proportional hazard models explored factors for post-CNS metastasis survival.

RESULTS

A total of 2323 patients were identified (589-IBC/1734-NI-IDC). Eighty-one IBC patients developed CNS metastasis, versus 154 NI-IDC patients. The 2-, 5-, and 10-year cumulative CNS metastasis incidence rates in IBC and NI-IDC were 9.8%, 15.8%, 17.4% and 6.5%, 10.1%, and 12.7%, respectively. This was significantly different between IBC and NI-IDC patients (P = .0037). Multicovariate competing risk regression models in IBC and NI-IDC patients showed no statistically significant associations with the risk of developing CNS metastasis, except neoadjuvant taxane use in NI-IDC patients (hazard ratio, 0.45; 95% confidence interval, 0.24-0.83; P = .011). The median follow-up was 7.2 years, and the median post-CNS metastasis OS was not significantly different between IBC (7.6 months) and NI-IDC (5.6 months) patients. One hundred ninety patients with CNS metastasis died. HER2-positive patients had better OS, with a median 14.1 versus 4.3 months (P < .0001). Age >50 years (P = .012) but not IBC status was a significant predictor of post-CNS metastasis survival.

CONCLUSION

IBC patients demonstrated higher CNS metastasis incidence rates but OS following CNS metastases is similar in both groups. HER2 status and age may play prognostic roles. Cancer 2018;124:2299-305. © 2018 American Cancer Society.

Racial and Socioeconomic Disparities Are More Pronounced in Inflammatory Breast Cancer Than Other Breast Cancers

Inflammatory breast cancer (IBC) is a rare yet aggressive form of breast cancer. We examined differences in patient demographics and outcomes in IBC compared to locally advanced breast cancer (LABC) and all other breast cancer patients from the Breast and Prostate Cancer Data Quality and Patterns of Care Study (POC-BP), containing information from cancer registries in seven states. Out of 7,624 cases of invasive carcinoma, IBC and LABC accounted for 2.2% (N = 170) and 4.9% (N = 375), respectively. IBC patients were more likely to have a higher number (P = 0.03) and severity (P = 0.01) of comorbidities than other breast cancer patients. Among IBC patients, a higher percentage of patients with metastatic disease versus nonmetastatic disease were black, on Medicaid, and from areas of higher poverty and more urban areas. Black and Hispanic IBC patients had worse overall and breast cancer-specific survival than white patients; moreover, IBC patients with Medicaid, patients from urban areas, and patients from areas of higher poverty and lower education had worse outcomes. These data highlight the effects of disparities in race and socioeconomic status on the incidence of IBC as well as IBC outcomes. Further work is needed to reveal the causes behind these disparities and methods to improve IBC outcomes.

Similar response profile to neoadjuvant chemotherapy, but different survival, in inflammatory versus locally advanced breast cancers

Inflammatory breast cancer (IBC) is a very aggressive form of breast cancer, as compared to locally advanced breast cancer (LABC). Neoadjuvant chemotherapy followed by surgery is the standard treatment in both cases. Whether IBC is less chemosensitive than LABC remains unclear. We retrospectively compared the rate of pathological complete response (pCR) to neoadjuvant chemotherapy in IBC and LABC. Methods: Patients with IBC or LABC treated with neoadjuvant anthracycline-based chemotherapy followed by surgery were selected from our institutional database. The primary endpoint was the pCR rate, defined as absence of invasive tumor in breast and axillary lymph nodes. Results: A total of 450 patients were included, 144 with IBC and 306 with LABC. The pCR rate was similar between the two groups, in the whole population (31%) and in each molecular subtype separately. Univariate analyses for pCR in IBC and LABC separately identified the same predictive variables, except the pathological type that was associated with pCR in LABC only, but not in IBC. IBC patients displayed shorter 5-year metastasis-free survival and overall survival than LABC patients in the whole population (57% and 69% versus74% and 88% respectively), and in each molecular subtype separately. The IBC phenotype was an independent prognostic feature. Similarly, IBC patients displayed shorter 5-year loco-regional relapse-free survival than LABC patients (86% versus 95%). Conclusions: Similar pCR rates to chemotherapy were found in IBC and LABC, suggesting that IBC is not less chemosensitive than LABC. Survival was shorter in IBC, suggesting that the corresponding poorer prognosis is more due to a higher metastatic risk and/or other feature(s) than to a lesser chemosensitivity.

Macrophages Enhance Migration in Inflammatory Breast Cancer Cells via RhoC GTPase Signaling

Inflammatory breast cancer (IBC) is the most lethal form of breast cancer. All IBC patients have lymph node involvement and one-third of patients already have distant metastasis at diagnosis. This propensity for metastasis is a hallmark of IBC distinguishing it from less lethal non-inflammatory breast cancers (nIBC). Genetic profiling studies have been conducted to differentiate IBC from nIBC, but no IBC cancer-cell-specific gene signature has been identified. We hypothesized that a tumor-extrinsic factor, notably tumor-associated macrophages, promotes and contributes to IBC’s extreme metastatic phenotype. To this end, we studied the effect of macrophage-conditioned media (MCM) on IBC. We show that two IBC cell lines are hyper-responsive to MCM as compared to normal-like breast and aggressive nIBC cell lines. We further interrogated IBC’s hyper-responsiveness to MCM using a microfluidic migration device, which permits individual cell migration path tracing. We found the MCM “primes” the IBC cells’ cellular machinery to become extremely migratory in response to a chemoattractant. We determined that interleukins −6, −8, and −10 within the MCM are sufficient to stimulate this enhanced IBC migration effect, and that the known metastatic oncogene, RhoC GTPase, is necessary for the enhanced migration response.