Classical-type invasive lobular carcinoma with HER2 overexpression: clinical, histologic, and hormone receptor characteristics

Lobular Carcinoma of the Breast: A Comprehensive Review with Translational Insights

The second most common breast carcinoma, invasive lobular carcinoma, accounts for approximately 15% of tumors of breast origin. Its incidence has increased in recent times due in part to hormone replacement therapy and improvement in diagnostic modalities. Although believed to arise from the same cell type as their ductal counterpart, invasive lobular carcinomas (ILCs) are a distinct entity with different regulating genetic pathways, characteristic histologies, and different biology. The features most unique to lobular carcinomas include loss of E-Cadherin leading to discohesion and formation of a characteristic single file pattern on histology. Because most of these tumors exhibit estrogen receptor positivity and Her2 neu negativity, endocrine therapy has predominated to treat these tumors. However novel treatments like CDK4/6 inhibitors have shown importance and antibody drug conjugates may be instrumental considering newer categories of Her 2 Low breast tumors. In this narrative review, we explore multiple pathological aspects and translational features of this unique entity. In addition, due to advancement in technologies like spatial transcriptomics and other hi-plex technologies, we have tried to enlist upon the characteristics of the tumor microenvironment and the latest associated findings to better understand the new prospective therapeutic options in the current era of personalized treatment.

HER2-positive invasive lobular carcinoma: a rare breast cancer which may not necessarily require anti-HER2 therapy. A population-based study

BACKGROUND

HER2-positive (HER2 +) invasive lobular breast cancer (ILC) is rare and poorly characterised. In particular, patient outcomes compared to those associated with HER2 + invasive ductal cancer (IDC) and HER2-negative (HER2 -) ILC, as well as the benefits of anti-HER2 therapy, are not well established.

METHODS

We analysed the data from the Côte d'Or Registry of Breast and Gynaecological Cancers (France) for all patients diagnosed with early-stage HER2 + ILC (62 cases), HER2 + IDC (833 cases) and HER2 - ILC (685 cases) between 1998 and 2015 to compare overall and disease-free survival (OS and DFS) between these groups in correlation with anti-HER2 therapy.

RESULTS

ILCs were associated with older age, larger tumours, lower histological grades, higher hormonal receptor positivity rates and multifocality, and more common endocrine therapy. OS and DFS between the three groups did not differ. We found that anti-HER2 therapy was associated with a survival benefit in patients with HER2 + IDC. In contrast, the survival of HER2 + ILC patients was not improved by anti-HER2 treatment, remaining close to that of HER2 - ILC patients.

CONCLUSION

HER2 + ILC seems not to be associated with better outcomes than HER2 + IDC but may not differ from HER2 - ILC in terms of survival.

Histiocytoid variant of invasive lobular breast carcinoma. A case report and literature review

Introduction

Histiocytoid breast carcinoma (HBC) is a variant of invasive lobular carcinoma. The occurrence of HBC is rare and the natural history and clinical course of HBC is still not well known due to limited numbers of reported cases. In reality, many tumors have been misdiagnosed and reported as benign lesions.

Case presentation

A 66-year-old- postmenopausal women, who has previous personal history of right breast invasive ductal carcinoma, for which she underwent right breast wide local excision with negative sentinel lymph node biopsy and received adjuvant radiotherapy and hormonal therapy. Two years later, a new left breast suspicious lesion was detected by Imaging. Breast Ultrasound showed left breast hypo-echoic area at 12-1 o'clock with irregular spiculated lesion 3 cm away from the nipple with posterior acoustic shadowing measuring 1 × 0.7 × 0.7 cm and mild tissue distortion with thicken cortical left Axillary lymph node. Mammography of both breasts confirmed the left breast lesion at 12o'clock with necrosis and irregular margins measuring 1.1 × 1.0 cm. MRI breasts showed, left breast heterogeneously enhancing mass at 12 o'clock with no other suspicious mass in the left or right breast. Ultrasound guided left breast biopsy of the suspicious lesion seen at 12-1 o'clock which confirmed the diagnosis of invasive lobular carcinoma, histiocytoid variant She underwent wire guided left breast wide local excision with left sentinel lymph node and axillary clearance. Final histopathology showed invasive lobular carcinoma, histiocytoid variant.

Clinical discussion

The recognition of histiocytoid breast carcinoma is often a challenge, particularly when histiocytoid tumor cells occur in a metastatic site before the primary diagnosis of breast cancer. An awareness of histological features are needed to make the accurate diagnosis.

Conclusion

Findings that support the correct diagnosis include identifying tumor cells with more cytological atypia, the presence of cytoplasmic vacuoles and secretions. Moreover, coexistence with invasive lobular carcinoma and/or lobular neoplasia and the use of immunohistochemistry to confirm their epithelial nature. clinico-radiological correlation is essential, as any discordance should trigger further diagnostic determination.

•Histiocytoid breast carcinoma (HBC) is a rare variant of invasive lobular carcinoma.

•An awareness of histological features are needed to make the accurate diagnosis.

•Metastases to skin can be missed as benign sinus histiocytes and xanthomatous dermal lesions.

•Close clinic-radiological correlation is essential, as any discordance should trigger further diagnostic determination.

Clinicopathological features of and neoadjuvant therapy for human epidermal growth factor receptor 2-positive classic invasive lobular carcinoma

Human epidermal growth factor receptor 2 (HER2)-positive classic invasive lobular carcinoma (ILC) is a rare entity, and its specific pathological characteristics and clinical behavior are unclear. Therefore, we retrospectively investigated the clinicopathological features of HER2-positive classic ILC and described HER2-targeted neoadjuvant chemotherapy outcome. Fourteen HER2-positive classic ILC cases were identified, their clinicopathological data were collected, and their clinical management was investigated. In general, HER2 positivity is associated with higher grade carcinoma in ductal lesions; however, our 14 cases had typical morphologic features of classic ILC. We did not identify unique morphologic features in HER2-positive classic ILC with the clinicopathological parameters examined, including age, menopausal status, histological grade, and hormone receptor status. Four of six patients who received HER2-targeted neoadjuvant chemotherapy had a pathological complete or partial response. Based on our findings, clinicopathological features of classic ILC may not predict HER2 overexpression or amplification. HER2-targeted neoadjuvant chemotherapy was effective against some HER2-positive classic ILCs. Taken together, these results demonstrate that HER2 immunohistochemistry and fluorescence in situ hybridization should be considered for all ILC patients regardless of subtype.

Lobular Breast Cancer: Histomorphology and Different Concepts of a Special Spectrum of Tumors

Simple Summary

Invasive lobular breast cancer (ILC) is a special type of breast cancer (BC) that was first described in 1941. The diagnosis of ILC is made by microscopy of tumor specimens, which reveals a distinct morphology. This review recapitulates the developments in the microscopic assessment of ILC from 1941 until today. We discuss different concepts of ILC, provide an overview on ILC variants, and highlight advances which have contributed to a better understanding of ILC as a special histologic spectrum of tumors.

Abstract

Invasive lobular breast cancer (ILC) is the most common special histological type of breast cancer (BC). This review recapitulates developments in the histomorphologic assessment of ILC from its beginnings with the seminal work of Foote and Stewart, which was published in 1941, until today. We discuss different concepts of ILC and their implications. These concepts include (i) BC arising from mammary lobules, (ii) BC growing in dissociated cells and single files, and (iii) BC defined as a morpho-molecular spectrum of tumors with distinct histological and molecular characteristics related to impaired cell adhesion. This review also provides a comprehensive overview of ILC variants, their histomorphology, and differential diagnosis. Furthermore, this review highlights recent advances which have contributed to a better understanding of the histomorphology of ILC, such as the role of the basal lamina component laminin, the molecular specificities of triple-negative ILC, and E-cadherin to P-cadherin expression switching as the molecular determinant of tubular elements in CDH1-deficient ILC. Last but not least, we provide a detailed account of the tumor microenvironment in ILC, including tumor infiltrating lymphocyte (TIL) levels, which are comparatively low in ILC compared to other BCs, but correlate with clinical outcome. The distinct histomorphology of ILC clearly reflects a special tumor biology. In the clinic, special treatment strategies have been established for triple-negative, HER2-positive, and ER-positive BC. Treatment specialization for patients diagnosed with ILC is just in its beginnings. Accordingly, ILC deserves greater attention as a special tumor entity in BC diagnostics, patient care, and cancer research.

HER2 Positive and HER2 Negative Classical Type Invasive Lobular Carcinomas: Comparison of Clinicopathologic Features

Human epidermal growth factor receptor 2 (HER2) positive (+) classical type invasive lobular carcinoma (cILC) of the breast is extremely rare and its clinicopathologic features have not been well characterized. We compared features of HER2(+) and HER2 negative (-) cILCs. A total of 29 cases were identified from the clinical database at our institution from 2011-2019; 9 were HER2(+) cILC tumors and 20 were HER2(-) cILC tumors. The results reveal that HER2(+) cILC group had significantly increased Ki-67 expression and reduced estrogen receptor (ER) expression compared to HER2(-) cILC group (both p < 0.05). In addition, HER2(+) cILCs tended to be diagnosed at a younger age and more common in the left breast, and appeared to have a higher frequency of nodal or distant metastases. These clinicopathologic features suggest HER2(+) cILC tumors may have more aggressive behavior than their HER2(-) counterpart although both groups of tumors showed similar morphologic features. Future directions of the study: (1) To conduct a multi-institutional study with a larger case series of HER2(+) cILC to further characterize its clinicopathologic features; (2) to compare molecular profiles by next generation sequencing (NGS) assay between HER2(+) cILC and HER2(-) cILC cases to better understand tumor biology of this rare subset of HER2(+) breast cancer; and (3) to compare molecular characteristics of HER2(+) cILC and HER2(+) high grade breast cancer in conjunction with status of tumor response to anti-HER2 therapy to provide insight to management of this special type of low grade breast cancer to avoid unnecessary treatment and related toxicity.

Single-Institute Review of HER-2/Neu-Positive Invasive Lobular Breast Carcinoma in an Arab Population

BACKGROUND Invasive lobular carcinoma is special subtype of breast cancer that has clinical behavior and morphology distinct from other breast cancer subtypes. It accounts for 5-15% of breast cancer. Overall, HER-2 gene amplification occurs at a significantly lower rate in ILC, but also has been linked to adverse outcomes. Most cases of ILCs with HER-2 overexpression and or amplification generally have the pleomorphic variant. We report the first series of cases from Saudi Arabia for this rare cancer in an Arab population. CASE REPORT Nine patients retrospectively were evaluated with HER-2/neu-positive ILC of the breast that were diagnosed and managed from 2003 to 2020. Four patients were diagnosed as early breast cancer, 3 had metastatic disease and 2 were locally advanced at their initial presentation. The mean age was 58 years; 30% were classic ILC and another 60% were of mixed non-classic variants (histologic pattern represented by nuclear pleomorphism). Management of patients with HER-2-positive ILC was performed according to standard multimodality breast cancer guidelines, consisting of surgery, chemotherapy with anti-HER-2/neu blockade, radiation, and endocrine therapy, based on stage and hormone status. CONCLUSIONS In conclusion, HER-2-positive invasive lobular carcinoma of the breast is uncommon in the Arab population, which has not been previously reported in the literature. Further studies are warranted to explore the biology, molecular characteristics, and clinical course in this group of patients.

Comparison of Overall Survival Between Invasive Lobular Breast Carcinoma and Invasive Ductal Breast Carcinoma: A Propensity Score Matching Study Based on SEER Database

Objective

Invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) account for most breast cancers. However, the overall survival (OS) differences between ILC and IDC remain controversial. This study aimed to compare nonmetastatic ILC to IDC in terms of survival and prognostic factors for ILC.

Methods

This retrospective cohort study used data from the Surveillance, Epidemiology and End Results (SEER) Cancer Database (www.seer.cancer.gov). Women diagnosed with nonmetastatic ILC and IDC between 2006 and 2016 were included. A propensity score matching (PSM) method was used in our analysis to reduce baseline differences in clinicopathological characteristics and survival outcomes. Kaplan-Meier curves and log-rank test were used for survival analysis.

Results

Compared to IDC patients, ILC patients were diagnosed later in life with poorly differentiated and larger lesions, as well as increased expression of estrogen receptors (ERs) and/or progesterone receptors (PRs). A lower rate of radiation therapy and chemotherapy was observed in ILC. After PSM, ILC, and IDC patients exhibited similar OS (HR=1.017, p=0.409, 95% CI: 0.967–1.069). In subgroup analysis of HR-negative, AJCC stage III, N2/N3 stage patients, or those who received radiotherapy, ILC patients exhibited worse OS compared to IDC patients. Furthermore, multivariate analysis revealed a 47% survival benefit for IDC compared to ILC in HR-negative patients who received chemotherapy (HR=1.47, p=0.01, 95% CI: 1.09–1.97).

Conclusions

Our results demonstrated that ILC and IDC patients had similar OS after PSM. However, ILC patients with high risk indicators had worse OS compared to IDC patients by subgroup analysis.

Human epidermal growth factor receptor 2 positive rates in invasive lobular breast carcinoma: The Singapore experience

BACKGROUND

Invasive lobular carcinomas (ILC) form 5%-10% of breast cancer and rarely show overexpression of human epidermal growth factor receptor 2 (HER2).

AIM

To describe the prevalence and prognostic factors of HER2 positive (HER2+) ILC in an Asian population.

METHODS

A retrospective review of patients with ILC seen between January 1985 and March 2018 at various SingHealth medical institutions was conducted. Demographic and clinical data were collected from medical records. We examined clinicopathological characteristics and survival in relation to HER2 status.

RESULTS

A total of 864 patients were included. Prevalence of HER2 positivity was 10.1% (87 patients). Compared with HER2 negative (HER2-) ILC, HER2+ ILC was associated with a higher proportion of estrogen receptor negative (24.4% vs 5.9%, P < 0.001), progesterone receptor negative (PR-) (40.2% vs 24%, P = 0.002) and grade 3 tumours (Grade 3, 29.0% vs 10.2%, P < 0.001). Overall survival rate was poorer in patients with HER2+ compared to HER2- ILC (56.7% vs 72.9% alive at 10 years; hazard ratio 1.87, 95% confidence interval: 1.21-2.90, P = 0.004). Based on multivariate analysis, negative prognostic factors for overall survival included HER2 positivity, PR negativity, older age, Indian ethnicity and higher tumour stage.

CONCLUSION

Prevalence of HER2+ ILC was 10.1%. HER2+ ILC was more likely to have poorer prognostic features such as estrogen receptor negative, PR- and higher tumour grade, and have a poorer survival.

Applying the New Guidelines of HER2 Testing in Breast Cancer

PURPOSE OF REVIEW

The human epidermal growth factor receptor 2 (HER2) is an important prognostic and predictive biomarker in the breast cancer. The American Society of Clinical Oncology/College of American Pathology (ASCO/CAP) has published HER2 testing guidelines in breast cancer. We herein reviewed the HER2 testing guidelines in breast cancer with a focus on the application of the current guidelines.

RECENT FINDINGS

The continual investigation of HER2 testing in breast cancer has resulted in updates in the HER2 testing guidelines. The current guidelines focus on the uncommon clinical scenarios and emphasize the coordination between immunohistochemistry and in situ hybridization results, in an effort to improve clarity and accuracy. The ASCO/CAP guidelines provide valuable recommendations to ensure the accurate evaluation of HER2 status in breast cancer patients through standardization. Additional studies, particularly those with long-term outcome data are still needed to validate the guideline recommendations, especially the uncommon cases.

Frequency, Clinicopathologic Characteristics, and Follow-up of HER2-Positive Nonpleomorphic Invasive Lobular Carcinoma of the Breast

OBJECTIVES

To investigate human epidermal growth factor receptor 2 (HER2)-positive nonpleomorphic invasive lobular carcinoma (ILC), which has rarely been addressed.

METHODS

Clinicopathologic characteristics and follow-up of HER2-positive nonpleomorphic ILCs were collected and compared to those of HER2-negative counterparts.

RESULTS

Twenty-one cases of HER2-positive nonpleomorphic ILCs were identified, 6.3% of the study population. Compared to HER2-negative nonpleomorphic ILC, patients with HER2 positivity were older (P < .05), likely to be hormonal receptor negative (P < .01), and had higher histologic grade and angiolymphatic invasion (P < .01). HER2 positivity in nonpleomorphic ILCs was associated with higher recurrence/metastasis with hazard ratio of 2.03 (P < .05). No patient who received neoadjuvant therapy achieved pathologic complete response, and HER2-targeted therapy tended to reduce recurrence/metastasis in patients with HER2-positive nonpleomorphic ILC.

CONCLUSIONS

Our results highlight the existence of HER2 positivity in nonpleomorphic ILCs and reinforce that HER2 is associated with worse prognosis in nonpleomorphic ILC.

Efficacy of Single-Agent Chemotherapy for Patients with Advanced Invasive Lobular Carcinoma: A Pooled Analysis from Three Clinical Trials

BACKGROUND

Data on the efficacy of chemotherapy regimens in patients with advanced invasive lobular carcinoma (ILC) of the breast are limited. We investigated the efficacy of single-agent eribulin for the treatment of advanced ILC when compared with invasive ductal carcinoma (IDC).

PATIENTS AND METHODS

Results from the eribulin arms of two phase III studies (305 [EMBRACE] and 301) and a single-arm, phase II study were pooled. The studies involved patients with metastatic breast cancer who had previously received treatment with an anthracycline and a taxane. In all three studies, the dose of eribulin mesylate was 1.4 mg/m² given on days 1 and 8 of a 21-day cycle. Overall survival (OS), progression-free survival (PFS), and response rates in patients with ILC were assessed and compared with data from patients with IDC.

RESULTS

In total, 1,152 patients were included in this analysis (118 patients with ILC and 1,034 patients with IDC). Median OS was similar in patients with ILC and IDC (13.4 vs. 13.5 months; hazard ratio [HR], 1.10; 95% confidence interval [CI], 0.87-1.38); as was median PFS (4.1 vs. 3.6 months; HR, 0.91; 95% CI, 0.72-1.14). There were no major differences in response rates between the two groups.

CONCLUSION

This retrospective analysis suggests that eribulin demonstrates similar efficacy in patients with ILC and IDC with metastatic disease who have previously received an anthracycline and a taxane.

IMPLICATIONS FOR PRACTICE

Data on the efficacy of chemotherapy regimens in patients with advanced invasive lobular carcinoma (ILC) of the breast are limited. This pooled retrospective analysis of three clinical studies demonstrates that the magnitude of benefit of eribulin in the metastatic setting did not differ between patients with ILC versus invasive ductal carcinoma (IDC), even when restricting for patients with estrogen receptor-positive/HER2-negative IDC.

Periocular Histiocytoid Carcinoma: Potential Diagnostic Challenges

Cutaneous histiocytoid carcinoma can occur as a primary tumor of the periocular region. Morphologically similar histiocytoid carcinomas arising as primary tumors of the breast have a predilection for orbital metastases. They can occasionally contain regions with prominent vacuolated cytoplasm and minimal nuclear atypia, which mimic benign histiocytic lesions. Differentiating nonneoplastic, primary neoplastic, and metastatic histiocytoid lesions involving the periorbita can be challenging for both the clinician and the pathologist, and this distinction has management implications. Herein, we present 3 cases to illustrate the challenges of diagnosing periocular histiocytoid carcinoma.

Mediator complex (MED) 7: a biomarker associated with good prognosis in invasive breast cancer, especially ER+ luminal subtypes

Background

Mediator complex (MED) proteins have a key role in transcriptional regulation, some interacting with the oestrogen receptor (ER). Interrogation of the METABRIC cohort suggested that MED7 may regulate lymphovascular invasion (LVI). Thus MED7 expression was assessed in large breast cancer (BC) cohorts to determine clinicopathological significance.

Methods

MED7 gene expression was investigated in the METABRIC cohort (n = 1980) and externally validated using bc-GenExMiner v4.0. Immunohistochemical expression was assessed in the Nottingham primary BC series (n = 1280). Associations with clinicopathological variables and patient outcome were evaluated.

Results

High MED7 mRNA and protein expression was associated with good prognostic factors: low grade, smaller tumour size, good NPI, positive hormone receptor status (p < 0.001), and negative LVI (p = 0.04) status. Higher MED7 protein expression was associated with improved BC-specific survival within the whole cohort and ER+/luminal subgroup. Pooled MED7 gene expression data in the external validation cohort confirmed association with better survival, corroborating with the protein expression. On multivariate analysis, MED7 protein was independently predictive of longer BC-specific survival in the whole cohort and Luminal A subtype (p < 0.001).

Conclusions

MED7 is an important prognostic marker in BC, particularly in ER+luminal subtypes, associated with improved survival and warrants future functional analysis.

Correlation of Prognostic Factors of Invasive Lobular Carcinoma with ADC Value of DWI and SUVMax of FDG-PET

Invasive lobular carcinoma (ILC) is the second most common kind of breast cancer. Diffusion weighted imaging (DWI) and positron emission tomography/computed tomography (PET/CT) are functional modalities for presenting the biological characteristics of breast cancer. The purpose of this article is to study the relationship between DWI or PET/CT and ILC's prognostic factors. The relationship between the apparent diffusion coefficient (ADC) values, standard uptake value (SUV)max and prognostic factors of ILC were statistically evaluated. The ADC values were lower in mass types of ILC. SUVmax was statistically higher in grade 3 and 4 background parenchymal enhancement and positive lymph node metastasis. ADC values of DWI and SUVmax of PET/CT can be helpful in the prediction of the prognosis of ILC.

Predicting discordant HER2 results in ipsilateral synchronous invasive breast carcinomas: experience from a single institution

With the emergence of multiple lines of highly effective Human Epidermal Growth Factor Receptor 2 (HER2) directed therapy, accurate identification of HER2 positive tumour has become a critical aspect in the histopathological analysis of breast cancers. Multifocal invasive breast carcinomas are relatively common, and given the aggressive inherent biology of HER2 positive disease, identification of even small tumours with HER2 positive status may be of importance for treatment planning. There are currently no clear guidelines as to whether all of these foci should be tested for HER2 status. We reviewed the results of 172 patients in whom HER2 in situ hybridisation (ISH) testing was performed on at least two ipsilateral synchronous invasive carcinomas. Discordant results in different invasive foci were relatively uncommon and occurred in only eight (5%) of the 172 patients. This showed a statistically significant correlation with similarly discordant oestrogen receptor (ER) results. In addition HER2 discordance was more likely amongst different tumour foci if these arose in distinct and separate areas of DCIS. An algorithm based on a combination of College of American Pathologists (CAP) recommendation for HER2 testing, differing ER status and background DCIS profile may be useful in detecting these discordant cases.

Time trends in incidence rates and survival of newly diagnosed stage IV breast cancer by tumor histology: a population-based analysis

Few contemporary data are available that compare incidence and survival of metastatic breast cancer between ductal and lobular carcinomas. Using the Surveillance, Epidemiology, and End Results-9 registries, we identified 10,639 patients with de novo metastatic breast cancer diagnosed from 1990 to 2011. Annual age-adjusted incidence rates and annual percent changes (APCs) were analyzed. Multivariable Cox regression models were used to investigate the impact of year of diagnosis and histology on overall survival. 9250 (86.9 %) patients had ductal and 1389 (13.1 %) had lobular carcinomas. Metastatic breast cancer incidence increased slightly over time for ductal (APC = +1.7, 95 % confidence interval (CI) = +1.0 to +2.4) and lobular carcinomas (APC = +3.0, 95 % CI = +1.8 to +4.3). Median overall survival was 22 months among the whole cohort. More recent year of diagnosis was associated with better overall survival only for patients with ductal carcinomas (interaction p value = 0.006), with an adjusted hazard ratio of death for every five-year increment in the date of diagnosis of 0.93 (95 % CI =  0.91-0.95) among ductal carcinomas, compared with 1.05 (95 % CI = 0.95-1.10) among lobular carcinomas. Overall survival was longer for lobular versus ductal carcinomas (28 versus 21 months, respectively; adjusted hazard ratio of death = 0.93, 95 % CI = 0.87-0.99), but the magnitude of this effect was attenuated among the cohort restricted to hormone receptor-positive tumors. In this population-based analysis, incidence rates of metastatic breast cancer at presentation increased slightly over time for both histologies, and particularly for lobular tumors. A modest improvement in metastatic breast cancer median overall survival was observed, but was apparently limited to ductal carcinomas.

Differences between invasive lobular and invasive ductal carcinoma of the breast: results and therapeutic implications

Invasive lobular carcinoma (ILC) is the second most common histologic subtype of breast cancer (BC): ILC differs from invasive ductal carcinoma (IDC) in its clinicopathological characteristics and responsiveness to systemic therapy. From the clinical standpoint, data suggest that ILC derives a distinct benefit from systemic therapy compared to IDC. In addition, comprehensive molecular analyses have been reported for ILCs, confirming that these tumors have specific genomic profiles compared to IDC. Despite these differences, clinical trials and practical clinical guidelines tend to treat BC as a single entity. Here we discuss these clinical and molecular data and their therapeutic implications.

Invasive lobular breast cancer and its variants: how special are they for systemic therapy decisions?

The WHO classification of breast tumors distinguishes, besides invasive breast cancer 'of no special type' (former invasive ductal carcinoma, representing 60-70% of all breast cancers), 30 special types, of which invasive lobular carcinoma (ILC) is the most common (5-15%). We review the literature on (i) the specificity and heterogeneity of ILC biology as documented by various analytical techniques, including the results of molecular testing for risk of recurrence; (ii) the impact of lobular histology on prediction of prognosis and effect of systemic therapies in patients. Though it is generally admitted that ILC has a better prognosis than IDC, is endocrine responsive, and responds poorly to chemotherapy, currently available data do not unanimously support these assumptions. This review demonstrates some lack of specific data and a need for improving clinical research design to allow oncologists to make informed systemic therapy decisions in patients with ILC. Importantly, future studies should compare various endpoints in ILC breast cancer patients among the group of hormonosensitive breast cancer.

Breast Cancer in Turkey: Clinical and Histopathological Characteristics (Analysis of 13.240 Patients)

OBJECTIVE

Breast cancer is the most common type of cancer and the leading cause of cancer related deaths in women in Turkey, as elsewhere around the world. However, detailed and systematic demographics, data on clinical and pathological characteristics, and treatment were largely unavailable in Turkey until now. This paper is intended to provide an analysis of clinical and pathological data on women registered in the National Breast Cancer Database (Ulusal Meme Kanseri Veri Tabanı [UMKVT]), established within Turkish Federation of Breast Diseases Societies (TMHDF) and available for use in Turkey since 2005.

MATERIALS AND METHODS

Clinical and pathological data on breast cancer patients registered online in the database from May 01, 2005 to May 01, 2011 were investigated. Parameters examined in patients included age, menopausal status, distribution of clinical and pathological stage, histological type, tumor diameter, histological grades, regional lymphatic stage, estrogen (ER), progesterone (PR), HER-2 receptors and molecular subtypes. Analysis results of these parameters were compared with literature data and discussed.

RESULTS

A total of 13,240 patients with breast cancer since April 07, 1992 were included in the study, and 99% of them were female. Female breast cancer patients whose requisite parameters had been completely entered in the database were included in the analysis. The mean age was 51.6 years (±12.6; range 12-97), 17% of them were younger than 40 years of age, and 45% were premenopausal. According to an analysis of age groups at diagnosis, the frequency of cancer peaked at the 45 - 49 age group with 16.7%, declining to 7.6% in the 65-69 age group, and then rose again. Most of the patients (78.7%) had invasive ductal, 7.8% were invasive lobular cancers, 9.8% were invasive mixed cancers (invasive ductal + invasive lobular), and 4% were other histological types (e.g. inflammatory, intracystic papillary, mucinous, etc.), respectively. Half of them (50%) had grade III histology. According to an analysis of pathological stages of all breast cancers (stage 0 - IV), 5% were stage 0, 27% were stage I, 44% were stage II, 21% were stage III, and 3% were stage IV breast cancer, respectively. The mean tumor diameter was 2.5 cm (±1.6; range 0.1-20 cm). The rates of lymphatic stages were pN0 50%, pN1 28%, pN2 15%, and pN3 7%, respectively. ER, PR, and HER-2 receptors were positive in 70%, 59%, and 23% of patients. A subtype analysis of tumors showed that 62% were type luminal A. This was followed by subtypes luminal B (15%), triple negative (15%), and HER-2 positive (8.5%).

CONCLUSION

As a conclusion patients with breast cancer in our breast cancer registry program were younger, and had more advanced disease, and worse prognostic factors than patients in developed countries.

Prognostic implications of lobular breast cancer histology: new insights from a single hospital cross-sectional study and SEER data

BACKGROUND

Invasive lobular breast cancer (ILC) is generally believed to have an increased risk for late relapse compared to invasive ductal breast cancer (IDC). However, the study most often referred to is a chemotherapy trial that mainly included node positive patients. We hypothesize that nodal status may influence the hazard of relapse since time of diagnosis differently in invasive ductal carcinoma (IDC) and ILC.

METHODS

Primary operable breast cancer patients from our institution diagnosed between 2000 and 2009 were studied. Multivariable analysis and subgroup analyses were performed to assess whether ILC carries a different prognosis compared to IDC. SEER data were used for external validation.

RESULTS

In lymph node negative patients, ILC carries a better prognosis regarding distant metastasis free interval (DMFI) (HR 3.242 (1.380-7.614), p = 0.0069) with a trend towards improved breast cancer specific survival (BCSS), over the entire study frame (UZ Leuven data). In lymph node positive patients, both DMFI (HR 0.466 (0.309-0.703), p = 0.0003) and BCSS (HR 0.441 (0.247-0.788), p = 0.0057) are significantly worse for ILC, especially after longer follow-up (>4-5 years) (UZ Leuven data). Similar results were found in the SEER cohort. Results remained identical when excluding screen detected cases (data not shown).

CONCLUSION

The prognostic impact of lobular histology not only depends on time since diagnosis but also on nodal status. The general believe that ILC have compromised late-term outcome compared to IDC seems untrue for the majority ( = node negative) of ILCs.

Intratumoral heterogeneity of the distribution of kinetic parameters in breast cancer: comparison based on the molecular subtypes of invasive breast cancer

PURPOSE

To evaluate the distribution pattern of kinetic parameters in breast cancers with various molecular subtypes.

MATERIALS AND METHODS

This study was approved by institutional review board and was compliant with HIPAA. We classified 192 invasive breast cancers of 186 patients into four molecular subtypes using hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) results and evaluated the distribution pattern of kinetic parameters (percent volume of kinetic types relative to the tumor volume) in the molecular subtypes.

RESULTS

In the delayed phase, all three types of kinetic parameter (persistent, plateau, and washout pattern) were observed in each molecular subtype without any dominant type of kinetic parameter. The percentages of washout pattern in the HR+ and HER2- type and triple negative (TN) cancers tended to be lower than those in the other molecular subtype cancers.

CONCLUSION

Each molecular subtype of invasive breast cancer showed a heterogeneous kinetic pattern in dynamic-contrast magnetic resonance imaging (MRI). The HR+/HER2- cancers and the TN cancers had relatively lower percentages of washout pattern. When a manual assessment of the kinetic parameters is performed, close attention should be paid in order to identify the malignant washout kinetic pattern, particularly in HR+/HER2- cancer and TN cancer.

Magnitude of Trastuzumab Benefit in Patients With HER2-Positive, Invasive Lobular Breast Carcinoma: Results From the HERA Trial

Purpose

To evaluate the benefit of adjuvant trastuzumab in patients diagnosed with human epidermal growth factor receptor 2 (HER2) –positive invasive lobular carcinoma (ILC) enrolled onto the Herceptin Adjuvant (HERA) trial.

Patients and Methods

Patients randomly assigned to receive one year of trastuzumab and one year of observation in the HERA trial were included (n = 3,401). Centrally reviewed estrogen receptor (ER), progesterone receptor (PgR), and HER2 copy numbers were used. First site-specific relapse pattern was evaluated for ILC and invasive ductal carcinoma (IDC). The magnitude of trastuzumab benefit was assessed using the Cox proportional hazards model for disease-free survival (DFS) and overall survival (OS).

Results

Median follow-up time was 4 years. A total of 187 ILC and 3,213 IDC patients were included. High Allred scores (6 to 8) were more common in patients with ILC than IDC for both ER (36.9% v 22.7%) and PgR (44.1% v 28.5%). A trend toward decreased HER2 copy number was observed in the ILC group. The ILC and IDC subgroups had similar patterns of first site of disease relapse. DFS hazard ratios (HRs) comparing 1 year of trastuzumab versus observation were 0.63 for ILC (95% CI, 0.34 to 1.15) and 0.77 for IDC (95% CI, 0.67 to 0.89; P for interaction = .49). The OS HRs comparing 1 year of trastuzumab versus observation were 0.60 for ILC (95% CI, 0.27 to 1.31) and 0.86 for IDC (95% CI, 0.71 to 1.06; P for interaction = .29).

Conclusion

In this retrospective analysis, there was no suggestion that patients in the ILC cohort experienced a different magnitude of benefit from adjuvant trastuzumab than those in the IDC cohort.

Survivin expression in breast lobular carcinoma: correlations with normal breast tissue and clinicomorphological parameters

The antiapoptotic protein survivin is rarely expressed in normal adult differentiated tissues, but it is often detected in their malignant counterparts. Immunohistochemically, we evaluated survivin expression in 19 cases of normal breast tissue and 64 cases of lobular breast carcinoma. The intensity of staining, percentage of labeled cells and subcellular location of survivin were assessed. We analyzed the quantitative differences of survivin expression between normal breast tissue and carcinomas. We also correlated survivin expression pattern in carcinomas with clinicomorphological parameters such as age of patients, grade, stage and size of primary tumor, lymph node metastasis, vascular invasion as well as estrogen and progesterone status. Survivin was detected in 10/19 cases of normal breast tissue (52.6%) and in 55/64 cases of lobular breast carcinoma (86%). The statistical analysis confirmed significant correlations between the assessed parameters in normal breast and lobular carcinoma. Furthermore, the expression of estrogen correlated significantly with the subcellular localization and intensity of survivin in carcinoma. However, no significant correlation was shown with regard to other clinicomorphological parameters. Our results suggest that survivin may be a valuable diagnostic marker, as well as a new independent prognostic parameter, in lobular breast carcinoma. Finally, our data support the hypothesis that lobular and ductal breast carcinomas seem to be different clinicomorphological entities.

Relapsed classic E-cadherin (CDH1)-mutated invasive lobular breast cancer shows a high frequency of HER2 (ERBB2) gene mutations

PURPOSE

We queried whether comprehensive genomic profiling using a next-generation sequencing-based assay could identify novel and unanticipated targets of therapy for patients with relapsed invasive lobular carcinoma (ILC).

EXPERIMENTAL DESIGN

DNA sequencing (Illumina HiSeq 2000) was conducted for 3,320 exons of 182 cancer-related genes and 37 introns of 14 genes frequently rearranged in cancer on indexed, adaptor-ligated, hybridization-captured libraries using DNA isolated from formalin-fixed paraffin-embedded sections from 22 histologically verified ILC.

RESULTS

A total of 75 genomic alterations were identified with an average of 3.4 alterations per tumor (range, 1-6), of which 35 were actionable for an average of 1.59 actionable alterations per patient (range, 0-3). Nineteen of 22 (86%) of the ILC samples harbored at least one actionable alteration. Six (27%) cases featured alterations in ERRB2 including 4 (18%) with ERBB2 mutation, 1 (5%) with an ERBB2 gene fusion, and 1 (5%) with an ERBB2 copy number gain (amplification). The enrichment of ERBB2 mutations/fusion in CDH1-mutated ILC (5 of 22, 23%) compared with the 5 ERBB2 mutations in a series of 286 non-CDH1-mutated breast cancers from which the ILC cases were obtained (5 of 286, 2%) was significant (P = 0.0006).

CONCLUSIONS

Comprehensive genomic profiling of relapsed CDH1-mutated ILC revealed actionable genomic alterations in 86% of cases, featured a high incidence of ERBB2 alterations, and can reveal actionable alterations that can inform treatment decisions for patients with ILC.

Tumor characteristics and the clinical outcome of invasive lobular carcinoma compared to infiltrating ductal carcinoma in a Chinese population

BACKGROUND

We sought to compare the baseline demographics, standard pathologic factors and long-term clinical outcomes between ILC and infiltrating ductal carcinoma (IDC) using a large database.

METHODS

Clinicopathologic features, overall survival (OS), and recurrence/metastasis-free survival (RFS) were compared between 2,202 patients with IDC and 215 patients with ILC.

RESULTS

ILC was significantly more likely to be associated with a favorable phenotype, but the incidence of contralateral breast cancer was higher for ILC patients than for IDC patients (8.4% vs. 3.9%; P=0.001). The frequencies of recurrence/metastasis (P = 0.980) and death (P = 0.064) were similar among patients with IDC and patients with ILC after adjustment for tumor size and nodal status. The median follow-up was 42.8 months.

CONCLUSIONS

Chinese women with ILCs do not have better clinical outcomes than their counterparts with IDC. Management decisions should be based on individual patient and tumor biologic characteristics, and not on lobular histology.