Metaplastic Carcinoma of the Breast Is More Aggressive Than Triple-negative Breast Cancer: A Study From a Single Institution and Review of Literature

Clinical outcomes by histologic pattern of early-stage metaplastic breast cancer: A single-institution retrospective study

PURPOSE

Metaplastic breast cancer (MpBC) is a rare, aggressive type of breast cancer composed of several histologic patterns. This study evaluated outcomes among the MpBC histologic patterns, which include spindle cell/sarcomatous, squamous, heterologous mesenchymal, and mixed.

PATIENTS AND METHODS

A retrospective chart review identified patients with early-stage MpBC diagnosed between January 1, 2010, and September 1, 2021. A matched control patient cohort with nonmetaplastic triple-negative breast cancer (TNBC) was selected. Associations between MpBC histologic patterns and disease characteristics were evaluated using chi-squared and Wilcoxon tests. Kaplan-Meier estimates and log rank tests assessed differences in recurrence-free survival (RFS) and overall survival (OS).

RESULTS

In the MpBC cohort (n = 106), histologic patterns included spindle cell/sarcomatous (34%), squamous (16%), heterologous mesenchymal (31%), mixed (18%), and other (1%). In patients with MpBC who received neoadjuvant chemotherapy (n = 32), residual cancer burden (RCB) was not found to be significantly different between the spindle cell/sarcomatous pattern versus other patterns (P = .81). In the entire MpBC cohort, patients with the spindle cell/sarcomatous pattern had inferior RFS (P = .02) and OS (P = .004) compared to patients with other patterns. There was no significant difference in RFS (P = .90) or OS (P = .90) between the MpBC and TNBC cohort.

CONCLUSION

RCB did not differ among the MpBC histologic patterns, but outcomes were inferior in patients with the spindle cell/sarcomatous pattern. Outcomes were also inferior in patients with MpBC receiving neoadjuvant versus adjuvant chemotherapy. Our study did not find a difference in outcomes between patients with MpBC versus nonmetaplastic TNBC. More investigation with larger sample sizes and biomarkers is warranted.

Successful regression of metaplastic triple-negative breast cancer with neoadjuvant chemotherapy and surgical intervention: A case report

RATIONALE

Metaplastic breast carcinoma (MBC) is a rare, aggressive subtype of triple-negative breast cancer, accounting for 0.2% to 5% of all breast cancers. It is associated with poor prognosis, twice the recurrence rate, and resistance to chemotherapy. This case report presents the treatment and outcome of a 39-year-old female with locally advanced stage III MBC.

PATIENT CONCERNS

The patient presented with a right breast mass, which had increased in size despite prior incomplete excision. She also had a contralateral breast mass, which was later confirmed as a benign neoplasm.

DIAGNOSES

The patient was diagnosed with metaplastic carcinoma of the right breast, classified as triple-negative breast cancer due to the absence of estrogen, progesterone, and human epidermal growth factor receptor 2 receptors. A biopsy revealed mesenchymal differentiation with a Nottingham grade 3 tumor measuring 35 mm, with high mitotic index and positive surgical margins.

INTERVENTIONS

The patient underwent neoadjuvant chemotherapy with taxane/carboplatin, followed by modified radical mastectomy and axillary lymph node dissection on the right, and subcutaneous mastectomy with sentinel lymph node dissection on the left. Post-surgery, she received adjuvant chemotherapy and radiotherapy.

OUTCOMES

Following neoadjuvant chemotherapy, significant morpho-metabolic tumor regression was observed. Postoperative imaging demonstrated near-complete resolution of the tumor and metastases. The patient's quality of life improved significantly, despite the emotional and physical challenges of the treatment.

LESSONS

This case highlights the potential efficacy of combining neoadjuvant chemotherapy, surgery, and adjuvant therapy in the management of MBC, emphasizing the need for careful monitoring of clinical, histological, and imaging data to guide treatment decisions for this rare cancer subtype.

The role of 18F-FDG PET/CT in detecting rare post-surgical cardiac metastasis of metaplastic breast carcinoma: a case report

Metaplastic carcinoma of the breast is an extremely rare and highly aggressive malignancy associated with a poor prognosis. Breast spindle cell carcinoma is a subtype of metaplastic carcinoma. We present the case of a 48-year-old woman who was found to have a breast nodule during a routine examination two years ago. Pathological examination following surgical resection confirmed the diagnosis of breast spindle cell carcinoma. One year later, a follow-up CT scan detected a progressively enlarging mass in the left lower lobe of the lung, which was histologically confirmed as metastatic breast spindle cell carcinoma after surgical excision. Recently, the patient developed chest discomfort and severe left thigh pain, prompting an18F-FDG PET/CT scan, which revealed metastases to the lung, heart, pleura, and femur. Subsequently, the patient's condition deteriorated rapidly within a short period. This report highlights the rare imaging findings of cardiac metastasis following surgery for breast spindle cell carcinoma, underscoring the highly aggressive nature of this tumor and the pivotal role of18F-FDG PET/CT in the post-operative monitoring of patients with breast spindle cell carcinoma.

TNMpBC-NeoBCSS model: a breast cancer specific survival prediction model for triple-negative metaplastic breast carcinoma patients with neoadjuvant therapy

The breast cancer specific survival (BCSS) benefits of Neoadjuvant therapy (NeoAT) for triple-negative metaplastic breast cancer (TNMpBC) was uncertain. This study aimed to develop a prediction model for assessing the BCSS for TNMpBC patients with NeoAT. The primary cohort of 1163 patients with TNMpBC, from which a nomogram was established based on the results of a LASSO regression analysis, was derived from multi-centers data in China and the SEER database. This model was further validated by an independent cohort of 155 TNMpBC patients with NeoAT, with discrimination and calibration assessed. Totally 155 (13.3%) TNMpBC patients received NeoAT, with 45 (29.0%) cases demonstrating pathologic complete response (pCR), were enrolled. Subjects acquired pCR had superior BCSS. Four variables significantly associated with BCSS were incorporated in the establishment of model: age at diagnosis, T stage, N stage, and response to NeoAT. This model was well validated, with a C-index of 0.82, and area under the curves of 0.838, 0.866 in training cohort, respectively, for 3- years and 5-years BCSS. Based on the cutoff scores from the TNMpBC-NeoBCSS model and calculated by X-tile analysis, patients in high risk group had a inferior BCSS (HR = 6.77, P < 0.0001) when compared with those in low-risk group. TNMpBC-NeoBCSS model provides a favorable tool for assessing the BCSS for the TNMpBC patients with NeoAT and may help doctors and TNMpBC patients optimally make decision on the necessity of neoadjuvant therapy on the basis of individual BCSS.

Therapeutic strategies and landscape of metaplastic breast cancer

Metaplastic breast cancer is a rare and heterogeneous subtype of breast cancer, associated with a poor prognosis. Its distinct biological behavior and morphological features contribute to resistance to standard treatment regimens. Hitherto, the optimal therapeutic strategy for metaplastic breast cancer remains underexplored. Herein, we review the literature on the treatment of metaplastic breast cancer, summarizing current local and systemic therapies, and discuss potential therapeutic targets and novel strategies based on its pathological and molecular characteristics. Targeted therapy and immunotherapy may provide more personalized treatment options, with the potential to improve the prognosis of this disease.

Metaplastic carcinoma of the breast containing three histological components: a case report

Malignant breast tumors mainly arise from the ductal and lobular epithelium, whereas sarcomas, which originate from the stromal tissues of the breast, account for less than 5% of cases. Mostly, these tumors consist of a single tissue type, rendering malignant breast tumors with three distinct tissue types exceedingly rare. We report a unique case of a malignant breast tumor comprising three tissue types: squamous cell carcinoma (approximately 25%), invasive ductal carcinoma (approximately 5%), and fibrosarcoma (approximately 70%). Given the case's rarity, pre-operative imaging and tumor biopsy failed to yield definitive diagnostic information, we detail the patient's clinical and therapeutic process, providing insights for physicians on clinical diagnosis and treatment.

Failure to progress: breast and prostate cancer cell lines in developing targeted therapies

Developing anticancer drugs from preclinical to clinical takes approximately a decade in a cutting-edge biomedical lab and still 97% of most fail at clinical trials. Cell line usage is critical in expediting the advancement of anticancer therapies. Yet developing appropriate cell lines has been challenging and overcoming these obstacles whilst implementing a systematic approach of utilizing 3D models that recapitulate the tumour microenvironment is prudent. Using a robust and continuous supply of cell lines representing all ethnic groups from all locales is necessary to capture the evolving tumour landscape in culture. Next, the conversion of these models to systems on a chip that can by way of high throughput cytotoxic assays identify drug leads for clinical trials should fast-track drug development while markedly improving success rates. In this review, we describe the challenges that have hindered the progression of cell line models over seven decades and methods to overcome this. We outline the gaps in breast and prostate cancer cell line pathology and racial representation alongside their involvement in relevant drug development.

CCN6 Suppresses Metaplastic Breast Carcinoma by Antagonizing Wnt/β-Catenin Signaling to Inhibit EZH2-Driven EMT

Metaplastic breast carcinomas (mBrCA) are a highly aggressive subtype of triple-negative breast cancer with histologic evidence of epithelial-to-mesenchymal transition and aberrant differentiation. Inactivation of the tumor suppressor gene cellular communication network factor 6 (CCN6; also known as Wnt1-induced secreted protein 3) is a feature of mBrCAs, and mice with conditional inactivation of Ccn6 in mammary epithelium (Ccn6-KO) develop spindle mBrCAs with epithelial-to-mesenchymal transition. Elucidation of the precise mechanistic details of how CCN6 acts as a tumor suppressor in mBrCA could help identify improved treatment strategies. In this study, we showed that CCN6 interacts with the Wnt receptor FZD8 and coreceptor LRP6 on mBrCA cells to antagonize Wnt-induced activation of β-catenin/TCF-mediated transcription. The histone methyltransferase EZH2 was identified as a β-catenin/TCF transcriptional target in Ccn6-KO mBrCA cells. Inhibiting Wnt/β-catenin/TCF signaling in Ccn6-KO mBrCA cells led to reduced EZH2 expression, decreased histone H3 lysine 27 trimethylation, and deregulation of specific target genes. Pharmacologic inhibition of EZH2 reduced growth and metastasis of Ccn6-KO mBrCA mammary tumors in vivo. Low CCN6 is significantly associated with activated β-catenin and high EZH2 in human spindle mBrCAs compared with other subtypes. Collectively, these findings establish CCN6 as a key negative regulator of a β-catenin/TCF/EZH2 axis and highlight the inhibition of β-catenin or EZH2 as a potential therapeutic approach for patients with spindle mBrCAs.  Significance: CCN6 deficiency drives metaplastic breast carcinoma growth and metastasis by increasing Wnt/β-catenin activation to upregulate EZH2, identifying EZH2 inhibition as a mechanistically guided treatment strategy for this deadly form of breast cancer.

Prognostic impact of histological subtyping in triple-negative breast cancer

The impact of special histological types (ST) in triple-negative breast cancer (TNBC) and its association with overall outcome has gained increasing relevance as survival has been linked to specific histological TNBC subtypes. We evaluated the clinicopathological and survival data of 598 patients with 613 TNBCs, including 464 TNBCs of no special type (NST) and 149 TNBCs ST (low-grade, n = 12, 8.1%; high-grade, n = 112, 75.2%; apocrine and androgen receptor-positive [APO AR], n = 25, 16.8%). Patients with low-grade TNBC ST and TNBC ST APO AR were significantly older (P < 0.001) and had a lower Ki67 index (P < 0.001) than those with TNBC NST. Patients with high-grade TNBC ST were significantly older (P = 0.006) and had poorer pathological responses to neoadjuvant chemotherapy (NAC) (P < 0.001) than those with TNBC NST. Significant survival differences were observed between low-grade TNBC ST, TNBC ST APO AR, high-grade TNBC ST, and TNBC NST in the entire study group (DFS, P = 0.002; DDFS, P = 0.001) and in the non-NAC subgroup (OS, P = 0.034; DFS, P = 0.001; DDFS, P < 0.001). Patients with low-grade TNBC ST had the best survival outcomes. Patients with high-grade TNBC ST showed significantly worse outcomes than those with TNBC NST (entire study group: OS, P = 0.049; DFS, P < 0.001; DDFS, P = 0.001; non-NAC subgroup: OS, P = 0.014; DFS, P < 0.001; DDFS, P < 0.001). We conclude that prognostic stratification of TNBC ST is ultimately important for optimizing the therapeutic management of patients with these rare tumor entities.

Analysis of clinicopathological characteristics and prognostic factors in 54 metaplastic breast carcinoma patients from northwest China

Objective

Metaplastic breast carcinoma (MBC) is a special type of morphologically heterogeneous and aggressively invasive breast cancer. MBC is characterized by the transformation of tumor epithelium into squamous epithelium and/or mesenchymal components, including differentiation into spindle cells, chondrocytes, and osteocytes. Due to its rarity and invasiveness, there is a paucity of research on MBC prognosis. Furthermore, there are currently no treatment guidelines for MBC. This study analyzed the clinicopathological characteristics, immunophenotype, and prognostic features of MBC. Our aim was to better characterize MBC, thereby identifying potential prognostic factors and new treatment methods. Moreover, we also describe an MBC case treated experimentally with anti-vascular targeted therapy.

Material and Methods

We retrospectively analyzed clinical pathological data on 54 female patients with MBC from Shaanxi Provincial People's Hospital and the XiJing Hospital of Air Force Medical University. These cases were diagnosed with MBC between January 1st, 2013, and October 1st, 2018. All patients were from the northwest region of China. The gross morphological, histological, and immunohistochemical features of MBC were analyzed. Kaplan-Meier analysis was used to calculate the survival rate, and univariate analysis was performed to identify significant prognostic factors. In addition, the treatment of an MBC patient with anti-angiogenic therapy was described, and a relevant literature review was conducted.

Results

MBC was diagnosed in 32 left breasts and 22 right breasts from 54 women aged 21-76 years (median age of 57 years). The maximum tumor diameter ranged from 0.6 to 14 cm (average of 4.1 cm). Of the 54 patients, 47 underwent surgical treatment, with lymph node metastasis found in 17.0% (8/47). According to the World Health Organization classification criteria for breast tumors, the study cohort consisted of 15 cases of squamous cell carcinoma, ten cases of spindle cell carcinoma, nine cases of carcinoma with associated stromal differentiation, 18 cases of mixed carcinoma, and two cases of adenocarcinoma with squamous differentiation. Based on the American Joint Committee on Cancer clinical staging criteria, the patients were classified as Stage I (10 cases, 18.5%), Stage II (26 cases, 48.1%), Stage III (11 cases, 20.4%), and Stage IV (7 cases, 13.0%). Immunohistochemical analysis revealed that 94.4% of patients had triple-negative breast cancer (TNBC), 47 cases showed mutant tumor protein 53 (TP53) expression, 29 cases showed positive epidermal growth factor receptor (EGFR) expression, 43 cases showed positive E-cadherin expression, and 37 cases showed positive Cluster of Differentiation 24 expression. The Ki-67 index ranged from 20% to 90%. Univariate analysis showed that the Ki-67 index was not significantly associated with either progression-free survival (PFS) or overall survival (OS) in MBC patients. Patients with negative axillary lymph nodes had significantly better PFS and OS than those with positive nodes (P < 0.05), and patients with clinical stage I-II disease had better PFS and OS than those with stage III-IV disease (P < 0.05). Patients treated with anthracycline-containing chemotherapy had significantly better PFS than those who did not receive chemotherapy. Univariate analysis revealed that the high expression of EGFR correlated with worse PFS (P < 0.05). The type of surgical approach employed did not affect the prognosis of MBC patients. Following the application of anti-angiogenic therapy, a rapid partial response was observed in an MBC patient with carcinoma and associated stromal differentiation. This patient subsequently underwent surgery and radiation therapy and has now achieved over 6 years of PFS.

Conclusion

MBC is a heterogeneous group of tumors with high malignancy and poor prognosis. The large majority is TNBC and exhibits unique immune phenotypes. The poor PFS of MBC patients may be related to EGFR expression, which could become a potential therapeutic target in these patients. Surgery remains the primary treatment method for MBC. The present study found that sentinel lymph node biopsy was feasible in appropriate patients, and that chemotherapy regimens incorporating anthracycline-class drugs did not appear to improve OS. Anti-angiogenic therapy holds promise as a potentially effective treatment approach for MBC, and the optimization of systemic treatment strategies should be a priority in the management of these patients.

Treatment outcomes and prognostic factors in nonmetastatic metaplastic breast cancer patients: a multicenter retrospective cohort study

BACKGROUND AND PURPOSE

Metaplastic breast carcinoma (BC-Mp) is an uncommon subtype that poses unique challenges. The limited information on patient prognosis and therapeutic strategies motivated our research initiative. We aimed to assess disease-free survival (DFS), overall survival (OS), and influential factors in patients with nonmetastatic BC-Mp.

MATERIALS AND METHODS

In this multicenter retrospective cohort study, clinicopathological data for nonmetastatic BC-Mp patients treated at four oncology units in Poland (2012-2022) were gathered.

RESULTS

Among 115 women (median age 61, range: 28-91), the median tumor size was 40 mm (range 20-130); 30% of patients exhibited positive local lymph nodes. The majority of patients presented with stage II (46%) and triple-negative breast cancer (TNBC) (84%). Radiotherapy was administered to 61% of patients. Surgical procedures included breast-conserving surgery in 31% of patients and mastectomy in 68%. Eighty-three per cent of patients received chemotherapy. The median estimated DFS and OS were 59 and 68 months, respectively. Multivariable analysis revealed that tumor size influenced DFS and OS (Hazard ratios [HR] = 1.02, 95%CI 0.01-0.03 for both endpoints) and taxanes application improved DFS (HR = 0.47, 95%CI 0.24-0.93), but other factors did not. For patients receiving neoadjuvant systemic therapy (N = 51), taxanes improved DFS and OS according to univariable analysis.

INTERPRETATION

Our findings highlight poor DFS and OS regardless of receiving optimal treatment, emphasizing the need for tailored therapeutic strategies for BC-Mp patients. Taxanes appear promising in a neoadjuvant setting, particularly within the current standard of care for the TNBC subtype.

Multimodal Imaging Features and Prognosis of Metaplastic Breast Carcinoma

RATIONALE AND OBJECTIVES

Metaplastic breast carcinoma (MBC) is an infrequent malignancy with an unfavorable prognosis, and there is a paucity of research on the multimodal imaging features of MBC. This study aimed to provide a comprehensive analysis of the multimodal imaging features, clinicopathological characteristics, and prognosis of MBC.

MATERIALS AND METHODS

A total of 36 patients with histologically confirmed MBC from 2012 to 2021 were included in the study. We analyzed the pre-treatment multimodal imaging features, including mammography, ultrasonography (US), and magnetic resonance imaging (MRI), as well as clinicopathology and prognosis of MBC. Follow-up data included local recurrence, distant metastasis, and overall survival (OS) rate.

RESULTS

MBC patients had a median age of 51 years at diagnosis. The most common histologic subtype was squamous cell carcinoma, with 86.1% of MBC being histological grade 3 and triple negative. The most common mammographic findings were irregular shape, non-calcification, and high density. The predominant US findings included irregular shape, parallel orientation, posterior acoustic enhancement, and hypoecho. On MRI, most masses exhibited irregular shape, spiculate margin, heterogeneous enhancement, Type II time intensity curve, and diffusion restriction on diffusion weighted images determined by apparent diffusion coefficient. According to breast imaging reporting and data system, mammography suggested malignancy in 50% of cases, US indicated a moderate to high suspicion of malignancy in 77.8% of cases, MRI revealed malignancy in all cases. At a median follow-up time of 48 months (range, 8-122 months) for 35 MBC patients, the local recurrence, distant metastasis, and OS rates were 11.4%, 28.6%, and 67.4%, respectively.

CONCLUSION

The benign features of MBC on mammography and US may cause misinterpretation. However, the inclusion of malignant features observed on MRI can improve diagnostic accuracy.

Better Local Disease Control With Mastectomy in Metaplastic Breast Carcinoma: Findings of a Retrospective Cohort

BACKGROUND

Metaplastic breast cancer (MBC) is a rare type of breast carcinoma with clinicopathological differences. The prognosis and treatment strategies for MBC are usually conflicting. In this study, we aim to present the clinicopathologic features, treatment strategies, and prognosis of our MBC patients.

MATERIAL AND METHODS

In our retrospective study, 18 metaplastic breast cancer patients treated in our institution between January 2005 and December 2022 were evaluated. Demographic and clinicopathological characteristics, surgical and systemic treatment options, locoregional recurrences, distant metastases, and overall survival (OS) of the MBC patients were retrieved from the patient files.

RESULTS

All patients were female; the median age was 54.42 ± 12.37 years. Most of the patients (n = 15, 83.33%) presented with palpable masses. Tumors were mostly triple-negative, with a high grade and a high Ki‑67 proliferation index. Spindle cell carcinoma and MBC with mesenchymal differentiation were the most common subtypes. Most of the patients underwent mastectomy (n = 11, 61.11%); breast-conserving surgery (BCS) was performed on seven (38,88%) patients. Lymph node positivity was detected in six of 18 patients (33.33%). Fewer patients (n = 4, 22.22%) received neoadjuvant chemotherapy. While local recurrence developed in two out of seven patients (28.57%) who underwent BCS, there was no local recurrence in patients who had mastectomy. The OS time varied according to tumor size and the presence of lymph node metastases (p <0.001; p = 0.005).

CONCLUSION

Metaplastic breast cancer is genetically heterogeneous and resistant to conventional treatment strategies. Mastectomy is still the surgical treatment method that is performed more frequently and provides better local control for patients with metaplastic breast cancer.

A Single-Center 18-Year Series of 73 Cases of Metaplastic Carcinoma of the Breast

Aim

To examine the clinical management of metaplastic breast cancer (MeBC), particularly the role of chemotherapy.

Methods

This retrospective study included patients with MeBC (n = 73) from a tertiary breast cancer center: the "Centre des Maladies du Sein of the CHU de Québec-Université Laval." The specimens were reviewed by two pathologists. Patient and tumor characteristics, systemic therapy (neoadjuvant and adjuvant), disease-free survival (DFS), and overall survival (OS) were recorded.

Results

The median follow-up was 57.2 months. The mean tumor size was 39.5 ± 32.1 (range, 1-200) mm. Most were in grade 3 (75.3%), without evidence of clinical nodal involvement (75.3%), and triple-negative (79.5%). Chemotherapy was given to 49 (67.1%) patients. Thirty-seven patients (50.7%) underwent a mastectomy, and 22/37 (59.5%) received radiotherapy. Adjuvant chemotherapy was given to 36 patients (49.3%), and nine (12.3%) patients were treated with neoadjuvant chemotherapy. The 5-year OS and DFS rates were 60.2% and 66.8%. Among the nine patients who received neoadjuvant chemotherapy, three (33.3%) achieved a partial response, three (33.3%) had stable disease, and three (33.3%) had disease progression. The use of chemotherapy, especially in the adjuvant setting, had a significant positive effect on 5-year OS (P=0.003) and 5-year DFS (P=0.004). Nodal involvement was associated with worse OS (P=0.049) but similar DFS (P=0.157). Lumpectomy was associated with better 5-year OS (P < 0.0001) and DFS (P=0.0002) compared with mastectomy.

Conclusion

MeBC represents a rare heterogeneous group of malignancies with poor prognosis. Adjuvant chemotherapy was associated with improved OS and DFS. Patients should be carefully selected for neoadjuvant chemotherapy.

Sonographic and clinicopathologic features of metaplastic breast carcinoma and infiltrating ductal carcinoma: a comparative single-center cohort study

Background

The rarity of metaplastic breast carcinoma (MBC) has resulted in limited sonographic data. Given the inferior prognosis of MBC compared to invasive ductal carcinoma (IDC), accurate preoperative differentiation between the two is imperative for effective treatment planning and prognostic prediction. The objective of this study was to assess the diagnostic accuracy of MBC and differentiate it from IDC by analyzing sonographic and clinicopathologic features.

Methods

In this retrospective cohort study, 197 women comprising 200 IDC lesions were enrolled between January 2012 and December 2021 and 20 women comprising 20 pure MBC lesions were enrolled between January 2019 and December 2019. A comparison was made between the sonographic and clinicopathologic characteristics of MBC and IDC.

Results

The results indicated that patients with MBC had a higher proportion of tumor grade 3 (95.0% vs. 32.5%; P<0.001), high Ki-67 expression (100.0% vs. 75.0%; P<0.001), and the triple-negative subtype (90.0% vs. 13.0%; P<0.001) as compared to those with IDC. On ultrasound (US) findings, MBC lesions tended to have a larger size (≥5 cm: 45.0% vs. 1.5%; P<0.001), regular shape (45.0% vs. 1.5%, P<0.001), circumscribed margin (40.0% vs. 0.5%, P<0.001), a complex cystic and solid echo pattern (50.0% vs. 3.5%; P<0.001), and posterior acoustic enhancement (95.0% vs. 14.5%; P<0.001). Additionally, MBC was more likely to be misinterpreted as a benign lesion by sonographers than was IDC (30.0% vs. 4.5%; P<0.001). Multilayer perceptron analysis revealed posterior acoustic enhancement, circumscribed margins, and size as distinguishing factors between these two tumor types. The estimated rates of local recurrence, distant metastasis, and 5-year overall survival in 19 cases with MBC were found to be 10.5%, 31.6%, and 65.0%, respectively.

Conclusions

MBC typically presents as a large breast mass with more benign US features in older women, findings which may facilitate its accurate diagnosis and differentiation from other breast masses.

Breast cancer and its therapeutic targets: A comprehensive review

Breast cancer is a common and deadly disease, so there is a constant need for research to find efficient targets and therapeutic approaches. Breast cancer can be classified on a molecular and histological base. Breast cancer can be divided into ER (estrogen receptor)-positive and ER-negative, HER2 (human epidermal growth factor receptor2)-positive and HER2-negative subtypes based on the presence of specific biomarkers. Targeting hormone receptors, such as the HER2, progesterone receptor (PR), and ER, is very significant and plays a vital role in the onset and progression of breast cancer. Endocrine treatments and HER2-targeted drugs are examples of targeted therapies now being used against these receptors. Emerging immune-based medicines with promising outcomes in the treatment of breast cancer include immune checkpoint inhibitors, cancer vaccines, and adoptive T-cell therapy. It is also explored how immune cells and the tumor microenvironment affect breast cancer development and treatment response. The major biochemical pathways, signaling cascades, and DNA repair mechanisms that are involved in the development and progression of breast cancer, include the PI3K/AKT/mTOR system, the MAPK pathway, and others. These pathways are intended to be inhibited by a variety of targeted drugs, which are then delivered with the goal of restoring normal cellular function. This review aims to shed light on types of breast cancer with the summarization of different therapeutic approaches which can target different pathways for tailored medicines and better patient outcomes.

Trends of incidence and mortality in metaplastic breast cancer and the effect of contralateral prophylactic mastectomy: A population-based study

INTRODUCTION

Metaplastic breast cancer (MBC) is considered rare and aggressive. We examined the epidemiology of and prognostic factors for MBC and investigated the effect of contralateral prophylactic mastectomy (CPM), because neither had been thoroughly examined previously.

METHODS

We obtained data from the Surveillance, Epidemiology, and End Results (SEER)-18(2000-2018) for epidemiological and survival analysis.

RESULTS

The age-adjusted incidence per 100,000 persons of MBC increased significantly from 0.12 to 0.35 [annual percent change (APC):2.95%, 95% confidence interval [CI], 1.73-4.19]. The incidence-based mortality increased from 0.01 to 0.12 (APC: 5.01%, 95% CI: 2.50-7.58). The incidence of MBC patients who underwent CPM significantly increased from 0.003 to 0.039 with an APC of 10.96% (95%CI, 7.26-14.78). Older patients and those with higher T classification were less likely to receive CPM. The multivariate Cox model showed that CPM was not an independent predictor of good prognosis for both overall survival (OS) and breast cancer-specific survival (BCSS) (pre-propensity score matching (PSM): OS: P = 0.331; BCSS: P = 0.462. post-PSM: OS: P = 0.916; BCSS: P = 0.967). Subgroup analysis showed that CPM still did not provide a survival benefit to any risk groups.

CONCLUSION

In this study, we demonstrated that the incidence and incidence-based mortality of MBC have increased over the past decades. Although the number of MBC patients who underwent CPM has significantly increased recently, CPM did not confer a survival benefit compared with unilateral mastectomy, indicating that the decision to undergo CPM should be considered carefully.

Epithelial to mesenchymal transition (EMT) in metaplastic breast cancer and phyllodes breast tumors

Epithelial-mesenchymal transition (EMT), a transdifferentiation program whereby epithelial cells acquire mesenchymal phenotype, is essential during embryonic development. EMT has also been implicated in cancer progression by conferring migratory and metastatic potential, as well as cell plasticity and stem cell like traits, to cancer cells. Metaplastic breast carcinoma (MBC) is a rare aggressive type of breast cancer characterized by the presence of heterologous elements, typically by the existence of epithelial and mesenchymal components. Phyllodes tumors (PTs) are uncommon fibroepithelial neoplasms consisting of epithelial and mesenchymal elements. Although various hypotheses have been proposed on the pathogenesis of these biphasic tumors, there is growing evidence supporting the theory that PTs and MBC could both correlate with cancer related EMT. This review summarizes the existing literature on the emerging role of EMT in the pathogenesis of MBC and PTs. Both malignant PTs and MBC are characterized by poor prognosis. Therefore, several anti-EMT targeting strategies such as blocking upstream signaling pathways, targeting the molecular drivers of EMT and targeting mesenchymal cells and the extracellular matrix, could potentially represent a promising therapeutic approach for patients suffering from these aggressive neoplasms.

Outcomes of Metaplastic Breast Cancer Versus Triple-Negative Breast Cancer: A Propensity Score Matching Analysis

PURPOSE

This study aims to compare the survival outcomes of metaplastic breast cancer (MPBC) with triple-negative breast cancer (TNBC) and identify prognostic factors that influence the survival outcomes of MPBC patients and TNBC patients.

METHODS

Patients with nonmetastatic MPBC or TNBC were reviewed from our database. Patients' clinicopathologic and molecular features were analyzed with respect to outcomes, including disease-free survival (DFS) and overall survival (OS). Propensity score matching (PSM) with a one-to-three matching between MPBC patients and TNBC patients was performed.

RESULTS

A total of 857 female patients (76 MPBC patients and 781 TNBC patients) were included in this study. A subgroup of triple-negative MPBC (n  =  60) was matched with TNBC (n  =  180) cases based on patient characteristics and treatments. Kaplan-Meier analysis indicated that the MPBC group was associated with worse OS and DFS before (P  =  0.0046 both) and after (P  =  0.011 and P  =  0.0046, respectively) PSM. Multivariable analysis revealed that a higher T stage (T > 2) (P  =  0.032) and higher lymph node stage (N3 vs. N0-2, P  =  0.012) were associated with worse OS after PSM. For DFS, the MPBC group (P  =  0.012), higher T stage (T > 2) (P  =  0.032), and higher lymph node stage (N3 vs. N0-2, P  =  0.045) were associated with worse DFS. Among the 76 MPBC patients, a higher T stage and mesenchymal differentiation were associated with worse OS (pT1/2 vs. pT3/4 and mesenchymal differentiation vs. other subtypes, P  =  0.007 and P  =  0.011, respectively).

CONCLUSIONS

Compared with TNBC, MPBC was associated with worse OS and DFS. Mesenchymal differentiation has a worse DFS than other subtypes of MPBC.

A unique presentation of metaplastic breast carcinoma, NOS: A case report

Key Clinical Message

A rare form of invasive breast carcinoma, NOS, also known as matrix-producing carcinoma made up of epithelial and mesenchymal components. Usually, they are triple negative and clinically aggressive and respond poorly to neoadjuvant systemic therapy.

Abstract

Metaplastic breast carcinomas (MBCs) are ductal carcinomas that undergo metaplasia to form nonglandular growth patterns. They are extremely rare, constituting less than 1% of all invasive breast carcinomas. Matrix-producing carcinoma is an exceedingly rare form of MBC distinguished by a ductal carcinomatous component with direct transition to areas of cartilaginous or osseous differentiation without the presence of an intervening spindle cell element. MBCs are clinically aggressive, but matrix-producing subtypes have a relatively better prognosis. The tumors are usually triple negative. Therefore, surgery and chemotherapy are the main therapeutic approaches. Our report describes this unique form of MBC with prominent osseous differentiation in a 33-year-old female patient. Its distinct histological features and peculiar clinical behavior necessitate a thorough understanding of this one-of-a-kind disease entity.

Metaplastic Breast Carcinoma: Clinicopathologic Features and Recurrence Score Results From a Population-based Database

OBJECTIVES

Metaplastic breast carcinoma (MBC) is a rare, aggressive form of cancer comprising epithelial and mesenchymal elements. The purpose of this study was to use population-based data to review the clinicopathologic, molecular features, and outcomes of MBC.

METHODS

Surveillance, Epidemiology, and End Results Program (SEER) data were used to identify MBC and invasive ductal carcinoma (IDC), no special type (NOS) between 2004 and 2015. Results from Oncotype DX's 21-gene assay linked to SEER registries were included for hormone receptor (HR)-positive tumors. χ 2 analysis was performed to determine the differences between MBC and IDC. Kaplan-Meier curves and multivariate Cox proportional hazards models were used for breast cancer specific death (BCSD).

RESULTS

Compared with IDC, NOS (n=509,864), MBC (n=3876) were more likely to present at an older age, be black, have negative lymph nodes, be >2 cm, grade 3, and triple negative (TN). All subtypes [HR-positive/human epidermal growth receptor 2 (HER2)-negative, HR-positive/HER2-positive, HR-negative/HER2-positive, and TN] had higher BCSD than IDC, NOS. 22.3% of MBC cases were HR-positive. HR-positive MBCs tested for a recurrence score (RS) 65% were high-risk compared with 16.8% of IDC, NOS. Within the MBC cohort, no significant differences in BCSD were identified with respect to different molecular subtypes. In a fully adjusted model, TN or HER2-positive status did not adversely affect BCSD compared with HR-positive MBC.

CONCLUSIONS

All molecular subtypes of MBC had a poorer prognosis compared with IDC, NOS. The different molecular subtypes of MBC did not affect the BCSD. HR-positive MBC patients had a significantly higher high-risk RS than IDC, NOS patients.

Metaplastic Carcinoma of the Breast: MRI Features with Clinical and Histopathologic Correlation

RATIONALE AND OBJECTIVES

Metaplastic carcinoma of the breast (MCB) is a rare type of breast carcinoma, and there are only limited data about the MRI findings of MCB. This article aimed to review the MRI features of MCB and correlate the MRI findings with clinical and histopathologic characteristics.

MATERIALS AND METHODS

A total of 23 patients were enrolled from a signal institution. The clinical data, histological diagnosis and MRI findings were retrospectively reviewed.

RESULTS

The average age of the 23 patients was 51.6 years. Twenty-one (91.3%) patients presented with a palpable mass. Squamous cell carcinoma was the most common subtype (10/23, 43.5%). Axillary lymph node metastasis was detected in 4 (17.4%) patients. The immunohistochemical profile showed the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor-2 (Her-2) expression were negative in 87.0%, 95.7%, and 91.3% of the patients respectively. On MRI, most cases exhibited an irregular mass (18/23, 78.3%) with high signal intensity on T2-weighted images (22/23,95.7%), non-circumscribed margin (19/23, 82.6%), heterogeneous enhancement (13/23, 56.5%), Type III (12/23, 52.2%) time intensity curve, and diffusion restriction (20/23, 87.0%) on diffusion weighted images (DWI).

CONCLUSION

MCB most commonly demonstrated definitely malignant MRI features, which may reflect the histopathologic characteristic of this rare and aggressive breast carcinoma.

Metaplastic breast carcinoma with osseous differentiation: A report of a rare case and literature review

Metaplastic matrix-producing breast carcinoma is a type of metaplastic breast carcinoma (MBC), which is a rare malignancy, accounting for 0.2-1% of breast carcinomas. A 52-year-old female visited a hospital because of a palpable painless mass in the right breast and was diagnosed with Breast Imaging Reporting and Data System (BI-RADS) category 4A via ultrasound (US) with a suspected positive lymph node at the right axillary region. Excision of the breast mass was performed and histopathologically confirmed that it was MBC with osseous differentiation. No distant metastasis was revealed before a modified radical mastectomy; however, metastasis to a lymph node of the right axillary region was observed (1/22). She received six cycles of TEC scheme chemotherapy (docetaxel, epirubicin, and cyclophosphamide, 21 days) and 5 weeks of radiotherapy (48 Gy/25 f/5 days a week), but without any follow-up examinations since radiotherapy. Twenty-four months after surgery, distant metastases to lungs and liver were confirmed and died 3 months later. This case provides valuable information for clinicians on MBC and suggests that further examination or biopsy should be performed to US BI-RADS 4A masses before surgery. In addition, regular postoperative follow-up plays important roles in detecting metastases early and improving prognosis.

Metaplastic breast cancer: an all-round multidisciplinary consensus

Metaplastic breast cancer (MpBC) is a rare and aggressive histologic subtype of breast cancer (BC) characterized by the presence of at least two cellular types, commonly epithelial and mesenchymal components. Despite growing evidence that MpBC is a unique entity, it has long been treated as a variant of nonspecial type (NST) BC. MpBC typically shows the phenotype of triple-negative breast cancer (TNBC), but compared to NST-TNBC, it is a relatively chemorefractory tumor associated with worse outcomes. Therefore, there is an urgent need to develop management guidelines specifically for MpBC to improve the prognosis of patients with early MpBC. This expert consensus aims to guide diagnosis and standardize clinical management of early MpBC among treating physicians. We provide guidance on the challenging radiological and pathological diagnosis of MpBC. Evidence on the involvement of genetic predisposition in the development of MpBC is also explored. We emphasize the importance of a multidisciplinary approach for the treatment of patients with early MpBC. The optimal surgery and radiotherapy approach is presented, as well as the opportunity offered by novel therapeutic approaches to increase treatment response in this chemoresistant subtype. Appropriate management of patients with MpBC is critical to reduce the high risk of local and distant recurrence that characterizes this disease.

The conundrum of metaplastic breast cancer: a single Egyptian institution retrospective 10-year experience (2011-2020)

BACKGROUND

Metaplastic breast cancer (MetBC) still represents a conundrum owing to its peculiar histogenesis and molecular drivers that render it extremely resistant to standard chemotherapy with ultimate dismal survival.

AIM

Describe the Egyptian National Cancer Institute's (NCI-E) experience with MetBC regarding its clinicopathologic features, treatment, and survival outcomes.

PATIENTS AND METHODS

Between 2011 and 2020, all MetBC patients presented to NCI-E were retrospectively evaluated. Original clinicopathologic data, therapeutic modalities, pathologic response to neoadjuvant chemotherapy (NACT), recurrence, and date of last follow-up/death were obtained from archived charts.

RESULTS

A cohort of 135 females, the median age was 52 years, and median follow-up period was 40 months (range: 2.6-130.8). Two-thirds were triple negative (TN). Squamous carcinoma was prevalent in 74.8% followed by carcinoma with osseous/chondroid differentiation, spindle cell, and low-grade adenosquamous carcinoma encountered in 13.3, 7.4, and 4.5%, respectively. Modified radical mastectomy was done in 59.3%, and positive nodes (pN+) were depicted in 37.7%. Median Ki-67 was 45% (range: 10-88); grade III and lymphovascular invasion (LVI) were observed in 83.7 and 43.7%, respectively. Stage II was the most common (49%), whereas initial stage IV was encountered in 8.1%. Anthracyclines/taxane combinations were rampant in adjuvant/neoadjuvant settings. The latter was employed in 41 patients, with only 3 cases (7.3%) achieving pathologic complete response (pCR), while moderate/significant residual tumor burden was found in 83%. The 5-year DFS and OS were 56.4 and 57.6%, respectively. Spindle cell carcinoma showed the worst survival parameters in univariate analysis. On the multivariate level, higher tumor stage (pT3 & 4), Ki-67 ≥ 45%, and TN subtype were independent variables for worse DFS and OS; age ≥ 52 years and the presence of LVI were independent features for worse DFS, whereas pN+ was an independent parameter for worse OS.

CONCLUSIONS

This study further solidifies the dreadful response of MetBC to conventional chemotherapy regimens employed in common non-metaplastic pathologies. A radical shift in treatment standards tailored to combat the molecular landscape of this distinctive tumor is urgently needed. Immunotherapy and molecularly targeted agents demonstrated promising results in phase I and II trials with hopeful sooner implementation in phase III studies.

Metaplastic Breast Carcinoma Revisited; Subtypes Determine Outcomes: Comprehensive Pathologic, Clinical, and Molecular Review

Metaplastic breast carcinoma (MpBC) is a heterogeneous group of tumors that clinically could be divided into low risk and high risk. It is important to recognize the different types of MpBC, as the high-risk subtypes have worse clinical outcomes than triple-negative breast cancer. It is important for the pathologist to be aware of the MpBC entities and use the proposed algorithms (morphology and immunohistochemistry) to assist in rendering the final diagnosis. Few pitfalls are discussed, including misinterpretation of immunohistochemistry and certain histomorphologies, particularly spindle lesions associated with complex sclerosing lesions.

Metaplastic carcinoma of the breast: matched cohort analysis of recurrence and survival

PURPOSE

Metaplastic breast carcinoma (MBC) is a rare subtype of breast cancer, defined as mammary carcinoma with squamous or mesenchymal differentiation, that may include spindle cell, chondroid, osseous, or rhabdomyoid differentiation patterns. The implications of MBC recurrence and survival outcomes remains unclear.

METHODS

Cases were ascertained from a prospectively maintained institutional database of patients treated from 1998 to 2015. Patients with MBC were matched 1:1 to non-MBC cases. Cox proportional-hazards models and Kaplan-Meier estimates were used to evaluate outcome differences between cohorts.

RESULTS

111 patients with MBC were matched 1:1 with non-MBC patients from an initial set of 2400 patients. Median follow-up time was 8 years. Most patients with MBC received chemotherapy (88%) and radiotherapy (71%). On univariate competing risk regression, MBC was not associated with locoregional recurrence (HR = 1.08; p = 0.8), distant recurrence (HR = 1.65; p = 0.092); disease-free survival (HR = 1.52; p = 0.065), or overall survival (HR = 1.56; p = 0.1). Absolute differences were noted in 8-year disease-free survival (49.6% MBC vs 66.4% non-MBC) and overall survival (61.3% MBC vs 74.4% non-MBC), though neither of these reached statistical significance (p = 0.07 and 0.11, respectively).

CONCLUSION

Appropriately-treated MBC may exhibit recurrence and survival outcomes that are difficult to distinguish from those of non-MBC. While prior studies suggest that MBC has a worse natural history than non-MBC triple-negative breast cancer, prudent use of chemotherapy and radiotherapy may narrow these differences, although studies with more power will be required to inform clinical management. Longer follow-up among larger populations may further elucidate the clinical and therapeutic implications of MBC.

The mixed subtype has a worse prognosis than other histological subtypes: a retrospective analysis of 217 patients with metaplastic breast cancer

OBJECTIVE

Metaplastic breast cancer (MpBC) is an aggressive subtype of all breast cancer. We aimed to investigate the clinicopathological features, treatments and prognoses of MpBC patients.

METHODS

We collected the data from MpBC patients diagnosed at Tianjin Medical University Cancer Hospital from 2010 to 2017. Kaplan Meier curves and Cox regression model were used to evaluating clinical outcomes and prognostic factors. After removing baseline differences by propensity score matching (PSM), we analyzed the prognosis between MpBC patients and invasive ductal carcinomas of no special type (IDC-NST) patients.

RESULTS

A total of 217 MpBC patients were subsumed. Of all histological subtypes, 45.1% were mixed subtypes, followed by with mesenchymal differentiation (27.2%), pure squamous (15.2%) and pure spindle (12.4%) subtypes. 69.6% of MpBC were triple-negative, 25.3% and 6.5% were HR-positive and HER2-positive. MpBC patients had worse survival compared to IDC-NST patients, with 5-year RFS of 73.8 and 83.6% (HR = 1.177 95%CI (1.171-2.676) P = 0.0068), and 5-year BCSS of 79.0% and 89.7% (HR = 2.187 95%CI (1.357-3.523) P = 0.0013). In the multivariate COX model, AJCC stage, mixed subtype and chemotherapy were independent prognostic factors. Mixed MpBC is more aggressive than pure and with heterologous mesenchymal differentiation subtypes. And whether squamous or spindle MpBC, mixed forms have shorter outcomes than pure forms.

CONCLUSIONS

MpBCs are associated with poorer prognoses than IDC-NSTs. They are heterogeneous with different clinicopathological features and clinical outcomes between histological subtypes. Pure and with heterologous mesenchymal differentiation subtypes have more survival benefits than the mixed subtype.

Carcinosarcoma: A Rare and Aggressive Breast Tumor in a Young Lady

Carcinosarcoma of the breast is a subtype of metaplastic breast carcinoma characterized by differentiation of the neoplastic epithelium toward mesenchymal-looking elements. It is a highly aggressive rare subtype of invasive breast neoplasm that exhibits a distinct histologic entity. Only a limited number of reports related to this type of disease have been reported. Here, we present a case of breast carcinosarcoma in a lady in her early 20s, which is relatively young among all cases published. It was challenging to achieve diagnosis preoperatively with histopathological evaluation of the ultrasound-guided tru-cut biopsy sample. With no evidence of distant metastasis clinically and radiologically, a surgical option was opted for. Left mastectomy and left chest wall reconstruction with deep inferior epigastric artery free flap were performed. Post-excision specimen was confirmed to be carcinosarcoma.

TROP2, androgen receptor, and PD-L1 status in histological subtypes of high-grade metaplastic breast carcinomas

AIMS

High-grade metaplastic breast carcinoma (HG-MBC) is a rare subtype of invasive breast carcinoma, mostly triple-negative. Metaplastic carcinomas are less responsive to neoadjuvant chemotherapy and are associated with a worse outcome than invasive carcinomas of no special type.

METHODS

Clinicopathological characteristics and immunophenotype were retrospectively assessed in a series of 65 patients diagnosed with HG-MBC between 2005 and 2017 at the Curie Institute (antibody panel: oestrogen receptor [ER], progesterone receptor [PR], androgen receptor [AR], human epidermal growth factor receptor 2 [HER2], programmed death ligand-1 [PD-L1], and trophoblast cell surface antigen 2 [TROP2]).

RESULTS

The median age at diagnosis was 59.5 years. Six (9%) patients had metastatic disease at diagnosis. Among the nonmetastatic patients receiving neoadjuvant therapy, 26% (5/19) achieved pathological complete response. Most tumours were pT1/pT2 (77%) and 12% were pN+. Histological subtypes (mixed, squamous, mesenchymal, and spindle cell) were 40%, 35.5%, 15.5%, and 9%, respectively. Tumour-infiltrating lymphocytes were low or moderate except when squamous differentiation was present. Most tumours were triple-negative (92%). AR and TROP2 were positive in 34% and 85% of the cases, respectively. PD-L1 was positive in tumour cells in 18% (cutoff: 1% of positive tumour cells) of the cases and in tumour-infiltrating immune cells in 40% (cutoff: 1% of tumour area) of the cases. Notably, spindle cell and mesenchymal metaplastic breast carcinomas were mostly PDL1-negative. Lastly, 21 (32.3%) cases were HER2-low, all being HER2 1+, with no HER2 2+.

CONCLUSION

Metaplastic breast carcinoma could benefit from tailored therapeutic strategies adapted to the phenotypic specificities of histological subtypes.

Case report and literature review on a large MBC with ulceration

RATIONALE

Metaplastic breast cancer (MBC) is a rare tumor of the breast, and skin ulceration of breast tumors is a difficult clinical problem that reduces the patient's quality of life.

PATIENT CONCERNS

There are currently no Standard Treatment Guidelines for MBC at present, and the treatment for the skin ulceration of breast tumors is limited in clinics.

DIAGNOSIS

Here, we report the case of a patient with a large MBC and skin ulceration, accompanied by exudation and odor.

INTERVENTION

The combined treatment of albumin paclitaxel and carrelizumab (anti-PD-1 immunotherapy) was effective in reducing the tumor, but it increased the severity of the skin ulceration. After taking traditional Chinese medicine, the skin ulceration healed completely. Then the patient underwent a mastectomy and radiotherapy.

OUTCOMES

The patient has a high quality of life and was in good condition after the comprehensive treatment.

LESSONS

This suggests that traditional Chinese medicine may have a good auxiliary therapeutic effect on the skin ulceration of MBC.

Clinical Characteristics and Prognosis of Metaplastic Breast Cancer Compared with Invasive Ductal Carcinoma: A Propensity-Matched Analysis

BACKGROUND

Metaplastic breast cancer (MpBC) is an aggressive histologic type of breast cancer. Although MpBC has a poor prognosis and is responsible for a large proportion of breast cancer mortalities, the clinical features of MpBC compared with invasive ductal carcinoma (IDC) are not well known, and the optimal treatment has not been identified.

METHODS

We retrospectively reviewed medical records of 155 MpBC patients and 16,251 IDC cases who underwent breast cancer surgery in a single institution between January 1994 and December 2019. The two groups were matched 1:4 by age, tumor size, nodal status, hormonal receptor status, and HER2 status using propensity-score matching (PSM). Finally, 120 MpBC patients were matched with 478 IDC patients. Disease-free survival and overall survival of MpBC and IDC patients both before and after PSM were analyzed by Kaplan-Meier survival, and multivariable Cox regression analysis was performed to identify variables affecting long-term prognosis.

RESULTS

The most common subtype of MpBC was triple-negative breast cancer, and nuclear and histologic grades were higher than those of IDC. Pathologic nodal staging of the metaplastic group was significantly lower than that of the ductal group, and more frequent adjuvant chemotherapy was performed in the metaplastic group. Multivariable Cox regression analysis indicated that MpBC was an independent prognostic factor for disease-free survival (HR = 2.240; 95% CI, 1.476-3.399, p = 0.0002) and overall survival (HR = 1.969; 95% CI, 1.147-3.382, p = 0.0140). However, survival analysis revealed no significant difference between MpBC and IDC patients in disease-free survival (HR = 1.465; 95% CI, 0.882-2.432, p = 0.1398) or overall survival (hazard ratio (HR) = 1.542; 95% confidential interval (CI), 0.875-2.718, p = 0.1340) after PSM.

CONCLUSION

Although the MpBC histologic type had poor prognostic factors compared with IDC, it can be treated according to the same principles as aggressive IDC.

Clinicopathological Features and Survival Outcomes of Metaplastic Breast Carcinoma – An Observational Multi-Centric Study

Purpose

To describe the clinicopathological features, and subtypes of metaplastic breast cancer (MpBC) in Pakistan and further to understand its response to treatment, including region-specific survival outcomes.

Patients and Methods

This retrospective cohort study was conducted at two private tertiary care hospitals in Karachi, Pakistan. Our selection criteria included a total of 215 patients who were diagnosed with MpBC at an age older than 18 years from 1994 to 2021. Data regarding clinicopathological features, staging, receptor status, treatment modalities, recurrence, and survival was obtained. Death was scored as an event, and patients who were alive were censored at the time of the last follow-up.

Results

The incidence of MpBC at our study centers is 3.21%. The median age of diagnosis was 50 years (range 22 to 80 years) and most patients presented at Stages II (45.1%) and III (44.2%). Among patients who received neoadjuvant chemotherapy, 31.7% achieved complete pathological response. The 3-year survival of those who received neoadjuvant chemotherapy was 96%. During our study, 19.1% of patients died and the median survival duration was 9 years 7 months 9 days. Survival of patients was significantly lower in patients who had metastasis (p-value = 0.042) and those who had tumor recurrence (p-value = 0.001).

Conclusion

Metaplastic breast cancer is an extremely rare variant of breast cancer with features that exist as a spectrum. Our study demonstrated considerable success with the use of neoadjuvant chemotherapy. The pathological complete response achieved in our study is one of the highest ever reported. Our success, though limited, warrants further research in the use of neoadjuvant chemotherapy in MpBC.

Metaplastic breast cancer: A review

Metaplastic breast cancer (MpBC) is an uncommon aggressive malignancy that is associated with a poor prognosis. Due to its rarity, the relationships between the clinical and pathological features of MpBC, treatment approach, and clinical outcomes remain underexplored. In the following review article, we synthesize the existing data on the clinical, pathological and genomic features, management, and outcomes of MpBC. We also identify potential targets for future clinical trials.

Recurrent Metaplastic Breast Cancer with Subtype Converted from Triple-Negative to HER2-Positive: A Case Report and Literature Review

Background

Metaplastic breast cancer (MBC) is an extremely rare malignant breast disease that has rarely been reported. The molecular subtype of MBC is mostly triple-negative, with a high recurrence rate and a worse prognosis. Due to its low HR- and HER2-positive rate, reports on endocrine and targeted therapy are very limited.

Case report

We report a case of infrequent triple-negative MBC, which, although at an early stage, quickly developed multiple recurrent lesions in the chest wall. The tumor relapsed repeatedly after comprehensive treatment, including surgery, chemotherapy and radiotherapy. However, pathological results after the third surgery suggested that the molecular subtype had changed from triple-negative to HER2-positive. The previous comprehensive treatment had not been able to effectively control the disease, but the patient achieved a long progression-free survival time through chemotherapy and trastuzumab targeted therapy after the subtype change. To date, there has been no recurrence for over eight years.

Conclusion

Among repeatedly relapsed MBC patients, further investigation should be taken into consideration. As in the case presented in our study, it is possible that the HER2 status can convert from negative to overexpression. Moreover, for HER2-positive MBC patients, anti-HER2 therapy is recommended. The decision-making process requires multidisciplinary involvement.

Primary squamous cell carcinoma of the breast: A case report and review of the literature

Primary squamous cell carcinoma (PSCC) of the breast, as a rare metaplastic breast cancer, currently has limited clinical data on its biological behavior, treatment and prognosis. At present, the optimal treatment of this tumor is still controversial. We reported a case of a 56-year-old woman with a mass on the right breast. She underwent a modified radical mastectomy and lymph node biopsy, which revealed that the tumor was a metaplastic squamous cell carcinoma with axillary lymph node metastasis, followed by traditional adjuvant chemotherapy and radiotherapy. The patient re-examined by PET/CT after two years in May 2017 and found a recurrence in the right chest wall, so resection of the recurring lesion was resected, then she was given postoperative adjuvant radiotherapy and chemotherapy. In August 2019, the patient re-examined by PET/CT, and there were pulmonary and mediastinal lymph node metastases. After 4 cycles of albumin paclitaxel plus cisplatin chemotherapy combined with nivolumab immunotherapy, the patient achieved complete response (CR), and then switched to nivolumab immune maintenance therapy. So far, no obvious metastasis has been seen. We believe that surgical treatment is necessary for PSCC of the breast;paclitaxel and cisplatin chemotherapy regimens and adjuvant radiotherapy are effective, but it may be resistant to radiotherapy; and immunotherapy may prolong the survival of patients with PSCC of the breast.

KEYNOTE-522 and male spindle cell carcinoma of the breast: A case report

Metaplastic Breast Cancer (MBC) is a rare group of tumors often presenting as triple-negative. MBC accounts for less than 1% of all breast cancers with the spindle cell variant comprising less than 0.5%. While rare, spindle cell carcinoma is the commonest subtype in the western world. It has a more aggressive biological behavior with increased risk of recurrence and death due to disease compared to triple negative breast cancers. There is no treatment guideline for management of MBC due to the rarity of the disease. Instead, treatment is theorized based off success with other types of aggressive breast and metaplastic cancers of different tissue. We present the first known case report of male spindle cell carcinoma of the breast treated with KEYNOTE-522 regimen. Therapy included a first phase with pembrolizumab (dose of 200 mg) every 3 weeks plus paclitaxel and carboplatin and second phase, with four cycles of pembrolizumab with doxorubicin-cyclophosphamide.

Prognosis and clinicopathological characteristics of metaplastic breast cancer: A meta-analysis

BACKGROUND

To compare the clinicopathological characteristics and prognosis of metaplastic breast cancer (MBC) and triple-negative breast cancer (TNBC).

METHODS

A meta-analysis was performed on relevant cohort or case-control studies retrieved by a literature search of the PubMed, EMBASE, Ovid, and Web of Science databases. Hazard ratio (HR) was used to evaluate disease-free survival (DFS) and overall survival (OS), and the odds ratio (OR) and corresponding 95% confidence interval (CI) was used to evaluate clinicopathological characteristics, including age, tumor diameter, lymph node metastasis status, distant metastasis status, TNM staging, and histological grade.

RESULTS

Nine studies were included in the meta-analysis. Compared with TNBC patients, the HRs for 5-year DFS and 5-year OS of those with MBC were 1.64 (95% confidence interval [CI] 1.36 - 1.98; P < .001) and 1.52 (95% CI 1.27 - 1.81; P < .001), respectively. The OR for age ≥ 50 years, tumor diameter ≤ 5 cm, lymph node-negative, distant metastasis, TNM stage III and IV, and histological grade 3 was 1.63 (95% CI 1.45-1.84), 0.29 (95% CI 0.14-0.58), 1.46 (95% CI 1.13-1.88), 1.59 (95% CI 0.89-2.81), 1.49 (95% CI 0.80-2.77), and 2.25 (95% CI 0.85-5.97), respectively.

CONCLUSION

Patients with MBC had worse prognosis than those with TNBC. Furthermore, regarding clinicopathological characteristics, patients with MBC mostly presented at ≥ 50 years of age, with tumor diameter > 5 cm, and negative lymph nodes at first diagnosis. Moreover, there were no statistically significant differences in the occurrence of distant metastasis, TNM stages III and IV, or histological grade 3. MBC treatment was not assessed in this study. Data from randomized controlled trials are needed to guide the treatment of patients with MBC.

Metaplastic breast carcinoma: an overview of the radio-pathologic features in retrospective cohort tertiary hospital

Background

Metaplastic breast carcinoma (MBC) is a rare type of breast carcinoma. It accounts for 0.2–1% of all invasive breast carcinoma. The aim of this study is to investigate the radiological features of this tumor and correlate them with the pathological findings.

Results

Of the 22 patients with pathology-proven metaplastic cancers, 18 patients  (81.82%) presented with a palpable mass. The majority of the mammogram findings were masses with irregular shapes (n = 12, 63.16%) and indistinct margins (n = 11, 57.89%). Similarly, the majority of the ultrasound studies showed masses with irregular shapes (n = 16, 72.73%) and indistinct margins (n = 8, 36.36%). Most of the echopatterns were complex or with heterogeneous textures, each presented in eight cases (36.36%). More than half of the cases had a posterior acoustic enhancement (n = 12, 54.55%). Most of the cases tested negative for estrogen receptors, progesterone receptors and HER2 protein, and they were high-grade tumors with a high proliferative index (Ki-67%) of > 15%.

Conclusion

MBC is a rare and distinct aggressive breast cancer with no definite characteristic imaging compared to other breast cancer. It shows a mass with irregular shape and indistinct margins in both mammogram and ultrasound. Additionally, it reveals posterior acoustic enhancement and rarely contains microcalcifications. The correlation with the pathological findings is crucial for the diagnosis and subsequent appropriate treatment.

Nomogram for the prediction of triple-negative breast cancer histological heterogeneity based on multiparameter MRI features: A preliminary study including metaplastic carcinoma and non- metaplastic carcinoma

Objectives

Triple-negative breast cancer (TNBC) is a heterogeneous disease, and different histological subtypes of TNBC have different clinicopathological features and prognoses. Therefore, this study aimed to establish a nomogram model to predict the histological heterogeneity of TNBC: including Metaplastic Carcinoma (MC) and Non-Metaplastic Carcinoma (NMC).

Methods

We evaluated 117 patients who had pathologically confirmed TNBC between November 2016 and December 2020 and collected preoperative multiparameter MRI and clinicopathological data. The patients were randomly assigned to a training set and a validation set at a ratio of 3:1. Based on logistic regression analysis, we established a nomogram model to predict the histopathological subtype of TNBC. Nomogram performance was assessed with the area under the receiver operating characteristic curve (AUC), calibration curve and decision curve. According to the follow-up information, disease-free survival (DFS) survival curve was estimated using the Kaplan-Meier product-limit method.

Results

Of the 117 TNBC patients, 29 patients had TNBC-MC (age range, 29–65 years; median age, 48.0 years), and 88 had TNBC-NMC (age range, 28–88 years; median age, 44.5 years). Multivariate logistic regression analysis demonstrated that lesion type (p = 0.001) and internal enhancement pattern (p = 0.001) were significantly predictive of TNBC subtypes in the training set. The nomogram incorporating these variables showed excellent discrimination power with an AUC of 0.849 (95% CI: 0.750−0.949) in the training set and 0.819 (95% CI: 0.693−0.946) in the validation set. Up to the cutoff date for this analysis, a total of 66 patients were enrolled in the prognostic analysis. Six of 14 TNBC-MC patients experienced recurrence, while 7 of 52 TNBC-NMC patients experienced recurrence. The DFS of the two subtypes was significantly different (p=0.035).

Conclusions

In conclusion, we developed a nomogram consisting of lesion type and internal enhancement pattern, which showed good discrimination ability in predicting TNBC-MC and TNBC-NMC.

Clinicopathologic Features of Metaplastic Breast Carcinoma: Experience From a Tertiary Cancer Center of North India

Introduction

Metaplastic breast cancer (MBC) is a rare malignancy that accounts for < 1% of all breast cancers. The aim of this study is to evaluate the clinicopathologic characteristics of MBC patients treated at a tertiary cancer center.

Materials and methods

In this study, the authors retrospectively analyzed the prospectively maintained data of MBC patients treated at a tertiary cancer care center in North India between January 2019 and July 2022.

Results

A total of 28 MBCs were identified. The median age of presentation was 47 years (range 27-81 years). Seventeen patients (60.7%) presented with clinical T3/T4 disease, and axillary nodal involvement was detected in 11 patients (39.3%) at presentation. Two patients had metastatic disease at presentation. A preoperative diagnosis of MBC on core biopsy was attained in five patients (17.9%), and the most common histologic subtype was sarcomatoid carcinoma. Triple-negative receptor status was observed in 15 patients (53.6%). Six patients (21.4%) underwent upfront breast conservation surgery and another six (21.4%) upfront mastectomy. Thirteen patients (46.4%) underwent mastectomy following neoadjuvant therapy. Definitive axillary nodal metastasis was found in eight patients (32%). Following neoadjuvant chemotherapy, five patients (35.7%) had stable disease, disease progression was evident in five patients (35.7%), partial response in four patients (28.6%), and no patient evinced complete response. Adjuvant postoperative radiation therapy was administered in 16 patients (57.1%). At a median follow-up of 13.2 months (range 4-26 months), 16 patients (57.1%) were alive with no evidence of disease, one patient (3.6%) was alive with disease, nine patients (32.1%) died of disease, and two patients (7.2%) died of other causes. One patient suffered from locoregional recurrence and nine patients developed distant metastasis.

Conclusion

MBC is an infrequent entity among breast carcinomas in India, which is similar to the reports of MBC worldwide. The diagnosis of MBC is difficult and requires the use of immunohistochemistry. Most of the cases in our study presented with a larger tumor size; however, they displayed a relatively lower incidence of nodal involvement as well as hormone receptor negativity. Being a rare and heterogeneous disease, large-scale studies are essential for better understanding and management of these tumors.

Combination of AURKA inhibitor and HSP90 inhibitor to treat breast cancer with AURKA overexpression and TP53 mutations

Breast cancer is the most common cancer among women worldwide. Researches show that Aurora kinase A (AURKA) is highly expressed in approximately 73% of breast cancer patients, which induces drug resistance in breast cancer patients and decreases the median survival time. AURKA regulates spindle assembly, centrosome maturation, and chromosome alignment. AURKA overexpression affects the occurrence and development of breast cancer. Besides AURKA overexpression, heat shock protein 90 (HSP90) maintains the survival and proliferation of tumor cells by stabilizing the structure of oncoproteins, including P53 mutants (mtP53). TP53 mutations accounted for approximately 13%, 40%, 80%, 33%, 71%, and 82% of luminal A, Luminal B, Luminal C, normal basal-like, HER2-amplified, and basal-like breast cancers, respectively. TP53 mutation can aggravate cell genome instability and enhance the invasion, migration, and resistance of cancer cell. This review describes the research status of AURKA and HSP90 in breast cancer, summarizes the structure, function, and the chaperone cycle of HSP90, elaborates the interrelation between HSP90, mtP53, P53, and AURKA, and proposes the combination of HSP90 inhibitor and AURKA inhibitor to treat breast cancer. Targeting AURKA and HSP90 to treat cancer with AURKA overexpression and TP53 mutations will help improve the specificity and efficiency of breast cancer treatment and solve the problem of drug resistance.

Metaplastic breast cancers and triple-negative breast cancers of no special type: are they prognostically different? A systematic review and meta-analysis

BACKGROUND AND AIMS

Metaplastic breast cancer (MBC) and triple-negative (TN) BC of no special type are often confounded with each other in terms of survival and prognosis. In this systematic study and meta-analysis, we evaluated the prognosis of each of these two different diagnoses.

METHODS

We conducted a systematic literature search and review using the MOOSE guidelines, through PUBMED database, the Ovid MEDLINE database, and the ISI Web of Science Citation Index Expanded (SCI Expanded). Overall survival (OS) and disease-free survival (DFS) were the main outcomes considered.

RESULTS

Our review eventually selected six independent studies, with a total of more than 59 519 patients. MBC was found to associate with worse OS compared to TNBC of no special type, with a significant 40% increased risk of death [summary hazard ratio (SHR) = 1.40, 95% confidence interval (CI): 1.30-1.50]. We found neither heterogeneity ( I2 = 0%) nor evidence of publication bias ( P = 0.82 and P = 0.49 by Begg's and Egger's test, respectively) between studies. No statistically significant difference was found between MBC and TNBC of no special type in terms of DFS (SHR = 1.17, 95% CI: 0.80-1.71).

CONCLUSION

This study demonstrates that TNBC of no special type and MBC have comparable DFS, although the latter presents a significantly worse prognosis in terms of OS. Despite DFS being similar in both subtypes, this did not result in significant OS benefits, with MBC score being the worse of the two diseases.

Metaplastic Breast Cancer: Characteristics and Survival Outcomes

Objectives

Metaplastic breast cancer (MBC) is a rare neoplasm accounting for <1% of all breast cancer. We evaluated the clinical characteristics and survival outcomes of MBC.

Methods

Patients diagnosed with pathologically proven MBC were reviewed from the institutional breast cancer database from 2000 to 2017.

Results

A total of 136 patients diagnosed with MBC were included in the study. The median age of the diagnosis was 60 years, and 60% of patients were stage II at diagnosis, and 22% were stage III. About two-thirds of the patients were triple-negative; 93% had nuclear grade III, and 25% had a lymphovascular invasion. Squamous differentiation (29%) was the most common histologic subtype, followed by the spindle subtype (21%). The most common distant metastases were lung (22%), followed by bone (13%). Moreover, 60% had a mastectomy, 19% had endocrine therapy, 58% had radiation, 51% received anthracycline-based chemotherapy, 26% had non-anthracycline chemotherapy, and 22% received no chemotherapy. In the entire cohort, the two-year overall survival (OS) and five-year OS were 79% and 69%, respectively, and the two-year progression-free survival (PFS) and five-year PFS were 72% and 61%, respectively. On multivariable analysis, the stage of MBC (stage III: hazard ratio (HR), 5.065 (95% confidence interval (CI), 1.02-25.27) (p=0.048)), poor functional status (Eastern Cooperative Oncology Group (ECOG) score, 2; HR, 24.736 (95% CI, 1.92-318.73) (p=0.014)), and distant metastasis to the brain (HR, 8.453 (95% CI, 1.88-38.04) (p=0.005)) and lung (HR, 42.102 (95% CI, 7.20-246.36) (p<0.001)) were significant predictors of decreased OS.

Conclusions

MBC demonstrated early disease progression and poor overall survival. The stage of MBC, decreased performance status, and metastasis to the lung and brain were independent poor prognostic factors.

Establishment of prognostic model for postoperative patients with metaplastic breast cancer: Based on a retrospective large data analysis and Chinese multicenter study

Purpose: Models for predicting postoperative overall survival of patients with metaplastic breast cancer have not yet been discovered. The purpose of this study is to establish a model for predicting postoperative overall survival of metaplastic breast cancer patients. Methods: Patients in the Surveillance, Epidemiology, and End Results database diagnosed with MBC from 2010 to 2015 were selected and randomized into a SEER training cohort and an internal validation cohort. We identified independent prognostic factors after MBC surgery based on multivariate Cox regression analysis to construct nomograms. The discriminative and predictive power of the nomogram was assessed using Harrell's consistency index (C-index) and calibration plots. The decision curve analysis (DCA) was used to evaluate the clinical usefulness of the model. We verify the performance of the prediction model with a Chinese multi-center data set. Results: Multifactorial analysis showed that age at diagnosis, T stage, N stage, M stage, tumor size, radiotherapy, and chemotherapy were important prognostic factors affecting OS. The C-index of nomogram was higher than the eighth edition of the AJCC TNM grading system in the SEER training set and validation set. The calibration chart showed that the survival rate predicted by the nomogram is close to the actual survival rate. It has also been verified in the SEER internal verification set and the Chinese multi-center data set. Conclusion: The prognostic model can accurately predict the post-surgical OS rate of patients with MBC and can provide a reference for doctors and patients to establish treatment plans.

Differences of Clinicopathological Features between Metaplastic Breast Carcinoma and Nonspecific Invasive Breast Carcinoma and Prognostic Profile of Metaplastic Breast Carcinoma

Introduction

Metaplastic breast carcinoma is a rare special type of breast cancer, which has distinguished clinical characteristics. We aimed to evaluate the clinicopathological features of metaplastic breast carcinoma compared with nonspecific invasive breast carcinoma and study the prognosis of metaplastic breast carcinoma.

Methods

We reviewed metaplastic breast carcinoma cases (n = 37) from January 2000 to December 2021 and nonspecific invasive breast carcinoma cases (n = 433) from January 2019 to December 2020 extracted from our institution retrospectively. The following variables were recorded, including the patients' general information, complications, T stage, expression of estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, Ki-67, molecular subtyping, lymph node status, skin or chest wall involvement, vessel carcinoma embolus, therapy modality (surgical treatments, chemotherapy, and radiotherapy), and survival.

Results

Patients with metaplastic breast carcinoma had more advanced disease than patients with nonspecific invasive breast carcinoma (T stage: P=0.0011). A greater proportion of metaplastic breast carcinoma presented with triple-negative breast cancer than nonspecific invasive breast carcinoma (79.41% vs. 12.47%, P ≤ 0.001). Our study showed that the skin or chest wall invasion was more frequent in metaplastic breast carcinoma patients (11.76% vs. 1.62%, P=0.005). The 5-year survival rate for metaplastic breast carcinoma patients was 57.66% (95% CI: 0.3195∼0.7667). No local recurrence was observed while distant metastasis occurred in 33.33% of patients with metaplastic breast carcinoma. Death due to disease occurred in 24.24% of patients with metaplastic breast carcinoma.

Conclusion

The majority of metaplastic breast carcinoma patients had more advanced disease and triple-negative disease than nonspecific invasive breast carcinoma patients. Also, metaplastic breast carcinoma patients had frequent skin or chest wall invasion and a high rate of distant metastasis and mortality.

Targeted therapy combined with immunotherapy in patients with breast infiltrating ductal carcinoma with axillary lymph node metastasis of metaplastic SCC

At present, the clinicopathological features, optimal treatment patterns, and prognosis of breast metaplastic squamous cell carcinoma (SCC) are not fully understood and are still controversial. Here, we report a 56‐year‐old female patient with breast infiltrating ductal carcinoma with axillary lymph node metastasis of metaplastic SCC admitted to our hospital. Their homology was clarified by comparing the gene mutation results of the two lesions, that is, the axillary lymph node lesion was a metastasis of breast metaplastic SCC. We treated the patient with Poly ADP‐ribose Polymerase (PARP) inhibitors in combination with immune checkpoint inhibitors (ICIs) and found that she could achieve clinical benefit from the combination regimen. We reported a successful diagnosis and treatment of this rare refractory disease and reviewed the literature on the characteristics, pathogenesis, and advances in the diagnosis and treatment of breast metaplastic SCC.