Over-using chemotherapy in the adjuvant setting

Avoidance of unnecessary or ineffective treatment should be one of the main goals in adjuvant breast oncology today. Unfortunately, both patients and doctors hunt for tiny statistical differences in survival curves. This search could not only lead to an oncological approach of unlimited addition that we will not be able to afford, but would also end inevitably in indeterminate overtreatment with substantial risks of unexpected toxic effects eating away whatever progress we might make. "Do not harm" remains the main principle in medicine. To be able to follow this rule, we need to better understand the biology of breast cancer. The mistake of "one treatment fits all" can only be changed when we critically review trial designs of adjuvant breast oncology. The risk of overtreatment is there and selection of precisely defined cohorts for phase 3 trials is necessary, despite pressure of scientific ambition, pragmatism, and demands of industry. The "add on" clinical trial design model accepts the inability to confirm that standard therapy is still necessary if a positive result from the addition of the new therapy is obtained. The same model can be applied to "extended" adjuvant treatments in breast cancer subtypes. Addition of "miraculin" to the standard of care should generate a new standard. Such trials that show a modest benefit on average at a population level take us a step away from refining care for the individual, and might support the use of multiple and costly interventions with potential short and long term side effects. It is essential to escalate treatment when necessary and to de-escalate when un-necessary.

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.

The role of histological subtype in hormone receptor positive metastatic breast cancer: similar survival but different therapeutic approaches

INTRODUCTION

This study describes the differences between the two largest histological breast cancer subtypes (invasive ductal carcinoma (IDC) and invasive (mixed) lobular carcinoma (ILC) with respect to patient and tumor characteristics, treatment-choices and outcome in metastatic breast cancer.

RESULTS

Patients with ILC were older at diagnosis of primary breast cancer and had more often initial bone metastasis (46.5% versus 34.8%, P = 0.01) and less often multiple metastatic sites compared to IDC (23.7% versus 30.9%, P = 0.11). Six months after diagnosis of metastatic breast cancer, 28.1% of patients with ILC and 39.8% of patients with IDC had received chemotherapy with a longer median time to first chemotherapy for those with ILC (P = 0.001). After six months 84.8% of patients with ILC had received endocrine therapy versus 72.5% of patients with IDC (P = 0.0001). Median overall survival was 29 months for ILC and 25 months for IDC (P = 0.53).

MATERIALS AND METHODS

We included 437 patients with hormone receptor-positive IDC and 131 patients with hormone receptor-positive ILC, all diagnosed with metastatic breast cancer between 2007-2009, irrespective of date of the primary diagnosis. Patient and tumor characteristics and data on treatment and outcome were collected. Survival curves were obtained using the Kaplan-Meier method.

CONCLUSIONS

Treatment strategies of hormone receptor-positive metastatic breast cancer were remarkably different for patients with ILC and IDC. Further research is required to understand tumor behavior and treatment-choices in real-life.

Heterogeneity of luminal breast cancer characterised by immunohistochemical expression of basal markers

BACKGROUND

Luminal A breast cancer defined as hormone receptor positive and human epidermal growth factor receptor 2 (HER2) negative is known to be heterogeneous. Previous study showed that luminal A tumours with the expression of basal markers ((cytokeratin (CK) 5 or CK5/6) or epidermal growth factor receptor (EGFR)) were associated with poorer prognosis compared with those that stained negative for basal markers. Prompted by this study, we assessed whether tumour characteristics and risk factors differed by basal marker status within luminal A tumours.

METHODS

We pooled 5040 luminal A cases defined by immunohistochemistry (4490 basal-negative ((CK5 (or CK5/6))- and EGFR-) and 550 basal-positive ((CK5 (or CK5/6+)) or EGFR+)) from eight studies participating in the Breast Cancer Association Consortium. Case-case comparison was performed using unconditional logistic regression.

RESULTS

Tumour characteristics and risk factors did not vary significantly by the expression of basal markers, although results suggested that basal-positive luminal tumours tended to be smaller and node negative, and were more common in women with a positive family history and lower body mass index.

CONCLUSIONS

Most established breast cancer risk factors were similar in basal-positive and basal-negative luminal A tumours. The non-significant but suggestive differences in tumour features and family history warrant further investigations.

Outcomes of special histotypes of breast cancer after adjuvant endocrine therapy with letrozole or tamoxifen in the monotherapy cohort of the BIG 1-98 trial

BACKGROUND

We investigated the outcomes of postmenopausal women with hormone receptor-positive, early breast cancer with special histotypes (mucinous, tubular, or cribriform) enrolled in the monotherapy cohort of the BIG 1-98 trial.

PATIENTS AND METHODS

The intention-to-treat BIG 1-98 monotherapy cohort (5 years of therapy with tamoxifen or letrozole) included 4922 women, of whom 4091 had central pathology review. Histotype groups were defined as: mucinous (N = 100), tubular/cribriform (N = 83), ductal (N = 3257), and other (N = 651). Of 183 women with either mucinous or tubular/cribriform tumors, 96 were randomly assigned to letrozole and 87 to tamoxifen. Outcomes assessed were disease-free survival (DFS), overall survival (OS), breast cancer-free interval (BCFI), and distant recurrence-free interval (DRFI). Median follow-up in the analytic cohort was 8.1 years.

RESULTS

Women with tubular/cribriform breast cancer had the best outcomes for all end points compared with the other three histotypes, and had less breast cancer recurrence (97.5% 5-year BCFI) than those with mucinous (93.5%), ductal (88.9%), or other (89.9%) histotypes. Patients with mucinous or tubular/cribriform carcinoma had better DRFI (5-year rates 97.8% and 98.8%, respectively) than those with ductal (90.9%) or other (92.1%) carcinomas. Within the subgroup of women with special histotypes, we observed a nonsignificant increase in the hazard of breast cancer recurrence with letrozole [hazard (letrozole versus tamoxifen): 3.31, 95% confidence interval 0.94-11.7; P = 0.06].

CONCLUSIONS

Women with mucinous or tubular/cribriform breast cancer have better outcomes than those with other histotypes, although the observation is based on a limited number of events. In postmenopausal women with these histotypes, the magnitude of the letrozole advantage compared with tamoxifen may not be as large in patients with mucinous or tubular/cribriform disease.

CLINICALTRIALSGOV

NCT00004205.

Clinicopathological Characteristics and Survival Outcomes of Invasive Cribriform Carcinoma of Breast: A SEER Population-Based Study

Invasive cribriform carcinoma (ICC) is a rare histologic subtype of breast cancer. We aimed to investigate the clinicopathological characteristics and survival outcomes of ICC.Using the Surveillance, Epidemiology, and End Results (SEER) database, we identified 233,337 female patients diagnosed with ICC (n = 618) or infiltrating ductal carcinoma (IDC) (n = 232,719). Univariate and multivariate survival analyses were utilized to calculate and compare disease-specific survival (DSS) and overall survival (OS). A 1:1 paired match was carried out on age, tumor stage, tumor grade, estrogen receptor (ER) status, and progesterone receptor (PR) status. Baseline characteristics and survival outcomes were also analyzed in ER-positive tumors. Subgroup analyses summarized the hazard ratio (HR) of IDC versus ICC using a forest plot.ICCs presented smaller size, lower grade, higher ER and PR positive rate, less nodal metastasis, and were less likely to be treated with mastectomy compared to IDCs. Five-year DSS rates were significantly better for patients with ICC than for patients with IDC (98.8% vs. 93%, P < 0.001). Five-year OS rates were 95.3% versus 90.1% (P < 0.001). After adjustment for common clinicopathological factors in the multivariate analysis, patients with ICC showed limited DSS advantage over the IDC group (HR = 0.75, 95% CI: 0.38-1.51, P = 0.421). No significant difference in DSS nor OS was observed in matched groups between ICC and IDC. Analysis among ER-positive patients revealed similar prognostic factors as among all patients. Survival analysis in different tumor grade subgroups showed no significant difference between ICC and IDC.ICCs have unique clinicopathological characteristics, higher rates of breast-conserving surgery, and more favorable prognosis compared to the overall IDC population. Difference in tumor grade between the 2 groups may partially explain the different outcome. Improved clinical and biological understanding of ICC might lead to more individualized and tailored therapy for breast cancer patients.

Treatment choices for patients with invasive lobular breast cancer: a doctor survey

RATIONALE, AIMS AND OBJECTIVES

Invasive lobular breast cancer (ILC) has distinct features that present challenges for management. We surveyed doctors regarding management approaches, opinions on quality of evidence supporting their practice, and future research needs.

METHODS

An online questionnaire was developed and circulated to breast cancer surgical, radiation and medical oncologists.

RESULTS

The questionnaire was completed by 88/428 doctors (20.6%); 22/56 (39.3%) surgeons, 21/64 (32.8%) radiation oncologists and 45/308 (14.6%) medical oncologists. The majority (65%) of surgeons were comfortable treating ILC patients using the same surgical management as patients with invasive ductal cancers (IDC). Furthermore, 25% would perform a similar surgery but would obtain larger gross margins. There was equipoise for radiation oncologists regarding whether or not ILC was an independent risk factor for local-regional recurrence after either breast-conserving surgery or mastectomy. Of those radiation oncologists who believe ILC is an independent risk factor for recurrence after mastectomy, 44.4% would offer radiation in the absence of usual indications. Medical oncologists approached systemic therapy for ILC patients similarly to those with comparable IDCs. Areas identified as most controversial and requiring future research were preoperative magnetic resonance imaging, radiotherapy post-mastectomy and the responsiveness of ILC to adjuvant chemotherapy compared with endocrine therapy.

CONCLUSIONS

There is a variation in doctors' beliefs, management and opinions regarding the quality of evidence for the management of ILC. Clinical trials specifically assessing the management of ILC are required to guide clinical practice.

Breast cancer genomics from microarrays to massively parallel sequencing: paradigms and new insights

Rapid advancements in massively parallel sequencing methods have enabled the analysis of breast cancer genomes at an unprecedented resolution, which have revealed the remarkable heterogeneity of the disease. As a result, we now accept that despite originating in the breast, estrogen receptor (ER)-positive and ER-negative breast cancers are completely different diseases at the molecular level. It has become apparent that there are very few highly recurrently mutated genes such as TP53, PIK3CA, and GATA3, that no two breast cancers display an identical repertoire of somatic genetic alterations at base-pair resolution and that there might not be a single highly recurrently mutated gene that defines each of the "intrinsic" subtypes of breast cancer (ie, basal-like, HER2-enriched, luminal A, and luminal B). Breast cancer heterogeneity, however, extends beyond the diversity between tumors. There is burgeoning evidence to demonstrate that at least some primary breast cancers are composed of multiple, genetically diverse clones at diagnosis and that metastatic lesions may differ in their repertoire of somatic genetic alterations when compared with their respective primary tumors. Several biological phenomena may shape the reported intratumor genetic heterogeneity observed in breast cancers, including the different mutational processes and multiple types of genomic instability. Harnessing the emerging concepts of the diversity of breast cancer genomes and the phenomenon of intratumor genetic heterogeneity will be essential for the development of optimal methods for diagnosis, disease monitoring, and the matching of patients to the drugs that would benefit them the most.

Invasive cribriform carcinoma of the breast: A report of nine cases and a review of the literature

Nine cases of infiltrating cribriform carcinoma (ICC) of the breast are reported and the clinicopathological features, particularly the imaging findings, are analyzed in the present study. Sonograms revealed that all masses exhibited a hypoechoic internal echo texture (9/9) and that a number of masses presented with an irregular shape (8/9), obscure boundary (5/9), partially microlobulated (5/9) or well-circumscribed (4/9) margins, and an inhomogeneous echo (8/9). Mammographic imaging revealed increased radiological density masses (6/8), and sand-like calcification was not observed in all patients. In two patients, the tumors were mammographically occult. Magnetic resonance imaging performed on one patient revealed a slightly high signal intensity on fat-saturated T1- and T2-weighted images. Following contrast enhancement, a homogeneous early enhancement was revealed with a quick ascent and quick descent time-density curve. Immunohistochemistry revealed that all ICCs expressed estrogen receptor and progesterone receptor, but that none were positive for human epidermal growth factor receptor 2. The Ki-67 labeling index was 3.75% (range, 2–5%) in the tumor tissue. Four patients were treated with mastectomy and the others with breast-conserving surgery. Six clinically node-negative patients underwent sentinel lymph node biopsy; three then received axillary lymph node dissection. Following surgery, three patients received adjuvant chemotherapy, radiotherapy and hormonal therapy, respectively. With a median follow-up time of 38 months (range, 4–70 months), one patient developed local recurrence following breast-conserving surgery; axillary lymph nodes and distant metastases were not observed. This study confirms that this type of carcinoma has unique biological characteristics and a favorable prognosis, but that it remains possible to experience local recurrence.

Invasive lobular breast cancer: the prognostic impact of histopathological grade, E-cadherin and molecular subtypes

Aims

The aim of this study was to compare breast cancer specific survival (BCSS) for invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) and, further, to evaluate critically the prognostic value of histopathological grading of ILC and examine E-cadherin as a prognostic marker in ILC.

Methods and results

The study comprised 116 lobular and 611 ductal breast carcinomas occurring between 1961 and 2008. All cases had been classified previously according to histopathological type and grade, stained for oestrogen receptor (ER), progesterone receptor (PR), antigen Ki67 (Ki67), epithelial growth factor receptor (EGFR), cytokeratin 5 (CK5) and human epidermal growth factor receptor 2 (HER2) and classified into molecular subtypes. For the present study, immunohistochemical staining for E-cadherin was performed. The Kaplan–Meier method and Cox proportional hazards models were used in the analyses. Grade 2 tumours comprised 85.3% of the lobular tumours and 51.9% of the ductal tumours. BCSS in ILC grade 2 was comparable to that of IDC grade 3. E-cadherin-negative ILC had a poorer prognosis compared to E-cadherin positive ILC and to IDC regardless of E-cadherin status.

Conclusions

The implication of histopathological grading may differ in ILC compared to IDC. E-cadherin may be useful in prognostication in ILC and thereby influence the determination of treatment strategies for this group of women.

Lobular breast cancers lack the inverse relationship between ER/PR status and cell growth rate characteristic of ductal cancers in two independent patient cohorts: implications for tumor biology and adjuvant therapy

BACKGROUND

Although invasive lobular carcinoma (ILC) of the breast differs from invasive ductal carcinoma (IDC) in numerous respects - including its genetics, clinical phenotype, metastatic pattern, and chemosensitivity - most experts continue to manage ILC and IDC identically in the adjuvant setting. Here we address this discrepancy by comparing early-stage ILC and IDC in two breast cancer patient cohorts of differing nationality and ethnicity.

METHODS

The clinicopathologic features of 2029 consecutive breast cancer patients diagnosed in Hong Kong (HK) and Australia (AUS) were compared. Interrelationships between tumor histology and other clinicopathologic variables, including ER/PR and Ki67, were analysed.

RESULTS

Two hundred thirty-nine patients were identified with ILC (11.8%) and 1790 patients with IDC. AUS patients were older (p <0.001) and more often postmenopausal (p <0.03) than HK patients. As expected, ILC tumors were lower in grade and proliferative rate, and more often ER-positive and HER2-negative, than IDC (p <0.002); yet despite this, ILC tumors were as likely as IDC to present with nodal metastases (p >0.7). Moreover, whereas IDC tumors exhibited a strongly negative relationship between ER/PR and Ki67 status (p <0.0005), ILC tumors failed to demonstrate any such inverse relationship (p >0.6).

CONCLUSION

These data imply that the primary adhesion defect in ILC underlies a secondary stromal-epithelial disconnect between hormonal signaling and tumor growth, suggesting in turn that this peritumoral feedback defect could reduce both the antimetastatic (adjuvant) and tumorilytic (palliative) efficacy of cytotoxic therapies for such tumors. Hence, we caution against assuming similar adjuvant chemotherapeutic survival benefits for ILC and IDC tumors with similar ER and Ki67, whether based on immunohistochemical or gene expression assays.

[Invasive breast cancer: the current WHO classification]

The World Health Organization (WHO) classification of tumors of the breast defines the international standards for tumor categorization and nomenclature. The fourth edition, published in 2012, provides an update on the current knowledge concerning the classification, immunohistology profile, differential diagnosis and genetics of these lesions. Compared to the previous edition, some terms have been modified, some entities were reclassified and some current molecular data have been added. This article focuses on invasive carcinomas. Definitions for histological diagnosis are supplemented by clinical, macroscopic and molecular characteristics as well as prognostic and predictive features.

Optimal adjuvant chemotherapy in breast cancer: selection of agents

Historically, the selection of the most effective adjuvant regimen for breast cancer patients was based on tumor size and nodal status but this approach took into account the stage only, without considering that the biology of the tumor matters as well, as breast cancer is a heterogeneous disease at the molecular level. In the present manuscript we will attempt to address the issue of selecting the most appropriate cytotoxic agents for adjuvant programs in the clinically and biologically distinct subgroups of endocrine responsive (luminal A and luminal B), HER2 positive and triple negative breast cancer patients.

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 carcinoma: molecular profiling and updates

The most significant contribution of molecular subtyping of breast carcinomas has been the identification of estrogen-positive and estrogen-negative tumor subtypes, which are 2 distinct entities with differing prognoses and requiring different therapy. Molecular and genetic analyses can provide prognostic information; however, a thorough histopathologic evaluation with an evaluation of predictive biomarkers will provide similar information. Knowledge of genetic alterations in these tumors will help identify novel therapeutic targets, which might have an impact on prognosis. Understanding the progression pathways involved in the transition of in situ carcinoma to invasive carcinoma might lead to efficient risk stratification in these patients.

The cribriform pattern identifies a subset of acinar predominant tumors with poor prognosis in patients with stage I lung adenocarcinoma: a conceptual proposal to classify cribriform predominant tumors as a distinct histologic subtype

The 2011 International Association for the Study of Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ERS) lung adenocarcinoma classification emphasizes the prognostic significance of histologic subtypes. However, one limitation of this classification is that the highest percentage of patients (∼40%) is classified as acinar predominant tumors, and these patients display a spectrum of favorable and unfavorable clinical behaviors. We investigated whether the cribriform pattern can further stratify prognosis by histologic subtype. Tumor slides from 1038 patients with stage I lung adenocarcinoma (1995-2009) were reviewed. Tumors were classified according to the IASLC/ATS/ERS classification. The percentage of cribriform pattern was recorded, and the cribriform predominant subtype was considered as a subtype for analysis. The log-rank test was used to analyze the association between histologic variables and recurrence-free probability. The 5-year recurrence-free probability for patients with cribriform predominant tumors (n=46) was 70%. The recurrence-free probability for patients with cribriform predominant tumors was significantly lower than that for patients with acinar (5-year recurrence-free probability, 87%; P=0.002) or papillary predominant tumors (83%; P=0.020) but was comparable to that for patients with micropapillary (P=0.34) or solid predominant tumors (P=0.56). The recurrence-free probability for patients with ≥10% cribriform pattern tumors (n=214) was significantly lower (5-year recurrence-free probability, 73%) than that for patients with <10% cribriform pattern tumors (n=824; 84%; P<0.001). In multivariate analysis, patients with acinar predominant tumors with ≥10% cribriform pattern remained at significantly increased risk of recurrence compared with those with <10% cribriform pattern (P=0.042). Cribriform predominant tumors should be considered a distinct subtype with a high risk of recurrence, and presence (≥10%) of the cribriform pattern is an independent predictor of recurrence, identifying a poor prognostic subset of acinar predominant tumors. Our findings highlight the important prognostic value of comprehensive histologic subtyping and recording the percentage of each histologic pattern, according to the IASLC/ATS/ERS classification with the addition of the cribriform subtype.

Invasive lobular carcinoma cell lines are characterized by unique estrogen-mediated gene expression patterns and altered tamoxifen response

Invasive lobular carcinoma (ILC) is a histologic subtype of breast cancer that is frequently associated with favorable outcomes, as approximately 90% of ILC express the estrogen receptor (ER). However, recent retrospective analyses suggest that patients with ILC receiving adjuvant endocrine therapy may not benefit as much as patients with invasive ductal carcinoma. On the basis of these observations, we characterized ER function and endocrine response in ILC models. The ER-positive ILC cell lines MDA MB 134VI (MM134) and SUM44PE were used to examine the ER-regulated transcriptome via gene expression microarray analyses and ER ChIP-Seq, and to examine response to endocrine therapy. In parallel, estrogen response was assessed in vivo in the patient-derived ILC xenograft HCI-013. We identified 915 genes that were uniquely E2 regulated in ILC cell lines versus other breast cancer cell lines, and a subset of these genes were also E2 regulated in vivo in HCI-013. MM134 cells were de novo tamoxifen resistant and were induced to grow by 4-hydroxytamoxifen, as well as other antiestrogens, as partial agonists. Growth was accompanied by agonist activity of tamoxifen on ER-mediated gene expression. Though tamoxifen induced cell growth, MM134 cells required fibroblast growth factor receptor (FGFR)-1 signaling to maintain viability and were sensitive to combined endocrine therapy and FGFR1 inhibition. Our observation that ER drives a unique program of gene expression in ILC cells correlates with the ability of tamoxifen to induce growth in these cells. Targeting growth factors using FGFR1 inhibitors may block survival pathways required by ILC and reverse tamoxifen resistance.

Luminal breast cancer: from biology to treatment

Oestrogen receptor (ER)-positive--or luminal--tumours represent around two-thirds of all breast cancers. Luminal breast cancer is a highly heterogeneous disease comprising different histologies, gene-expression profiles and mutational patterns, with very varied clinical courses and responses to systemic treatment. Despite adjuvant endocrine therapy and chemotherapy treatment for patients at high risk of relapse, both early and late relapses still occur, a fact that highlights the unmet medical needs of these patients. Ongoing research aims to identify those patients who can be spared adjuvant chemotherapy and who will benefit from extended adjuvant hormone therapy. This research also aims to explore the role of adjuvant bisphosphonates, to interrogate new agents for targeting minimal residual disease, and to address endocrine resistance. Data from next-generation sequencing studies have given us new insight into the biology of luminal breast cancer and, together with advances in preclinical models and the availability of newer targeted agents, have led to the testing of rationally chosen combination treatments in clinical trials. However, a major challenge will be to make sense of the large amount of patient genomic data that is becoming increasingly available. This analysis will be critical to our understanding how intertumour and intratumour heterogeneity can influence treatment response and resistance.

Tailoring adjuvant treatments for the individual patient with luminal breast cancer

Estrogen Receptor-positive/HER-2 negative breast cancers represent a heterogeneous group of tumors. Luminal A and B tumor subtypes can be identified through immunohistochemical assessment of estrogen and progesterone receptor, Ki-67 and HER-2 status. Patients with high levels of expression of steroid hormone receptors and low proliferation (Luminal A) are commonly cured with endocrine therapy alone. Patients with doubtful endocrine responsiveness or with high proliferation index (Luminal B/Her-negative) require the addition of chemotherapy to the best endocrine therapy. Controversies still exist on the identification of those patients who do not benefit from chemotherapy. Tailored adjuvant treatments should be considered in the therapeutic algorithm of patients with luminal tumors.

Invasive lobular carcinoma of the breast: patient response to systemic endocrine therapy and hormone response in model systems

Invasive lobular carcinoma of the breast (ILC) represents 10-15% of all newly diagnosed breast cancers, affecting ∼30,000 women annually in the United States. However, ILC is critically understudied as a breast cancer subtype. Though the vast majority of ILC are estrogen receptor-positive and present with overall favorable biomarkers, ILC patients do not benefit from improved outcomes versus other breast cancer patients. Patient outcomes, in particular in response to endocrine therapies, are not well understood in ILC, due in large part to the lack of prospective identification in large clinical trials. Further, there is a lack of laboratory models to study cell signaling, hormone response, and endocrine resistance in ILC. In this review, we provide an overview of clinicopathological features of ILC tumors, discuss issues with clinical management, and highlight the disconnect between ILC biomarkers and patient outcomes. We review currently available data on ILC patient outcomes, with a focus on response to endocrine therapy. Additionally, we describe currently available laboratory models for understanding hormone response in ILC cells, and review current data on these model systems. The promise for new insight into ILC, based on extensive representation of the disease in recent large scale genomic studies, is also discussed. Increasing understanding of endocrine response in ILC represents a critical area for future research to improve patient outcomes for this understudied breast cancer subtype.

Examining the pathogenesis of breast cancer using a novel agent-based model of mammary ductal epithelium dynamics

The study of the pathogenesis of breast cancer is challenged by the long time-course of the disease process and the multi-factorial nature of generating oncogenic insults. The characterization of the longitudinal pathogenesis of malignant transformation from baseline normal breast duct epithelial dynamics may provide vital insight into the cascading systems failure that leads to breast cancer. To this end, extensive information on the baseline behavior of normal mammary epithelium and breast cancer oncogenesis was integrated into a computational model termed the Ductal Epithelium Agent-Based Model (DEABM). The DEABM is composed of computational agents that behave according to rules established from published cellular and molecular mechanisms concerning breast duct epithelial dynamics and oncogenesis. The DEABM implements DNA damage and repair, cell division, genetic inheritance and simulates the local tissue environment with hormone excretion and receptor signaling. Unrepaired DNA damage impacts the integrity of the genome within individual cells, including a set of eight representative oncogenes and tumor suppressors previously implicated in breast cancer, with subsequent consequences on successive generations of cells. The DEABM reproduced cellular population dynamics seen during the menstrual cycle and pregnancy, and demonstrated the oncogenic effect of known genetic factors associated with breast cancer, namely TP53 and Myc, in simulations spanning ∼40 years of simulated time. Simulations comparing normal to BRCA1-mutant breast tissue demonstrated rates of invasive cancer development similar to published epidemiologic data with respect to both cumulative incidence over time and estrogen-receptor status. Investigation of the modeling of ERα-positive (ER+) tumorigenesis led to a novel hypothesis implicating the transcription factor and tumor suppressor RUNX3. These data suggest that the DEABM can serve as a potentially valuable framework to augment the traditional investigatory workflow for future hypothesis generation and testing of the mechanisms of breast cancer oncogenesis.

Invasive lobular carcinoma stable for 4.5 years in a postmenopausal woman user of hormone therapy for 25 years

We present a case of a 72-year-old woman referred to the breast disorder service due to abnormalities on mammography and breast ultrasound. The patient reported using different hormone therapy (HT) formulations during 25 years and had stopped taking HT for 4 years. Physical examination showed no alterations in the breasts or axilla. Mammography from 2012 detected asymmetry at the 3 o'clock position in the anterior right breast. Ultrasound revealed an irregular, hypoechoic mass with indistinct margins, and posterior acoustic shadowing. A retrospective analysis of mammographies from 2007, 2009 and 2010 showed that a very subtle asymmetry had existed since 2007. Follow-up imaging demonstrated no change in asymmetry during 4.5 years. The patient underwent breast-conserving therapy and sentinel lymph node biopsy. Histopathologic examination demonstrated classic invasive lobular carcinoma. There were no sentinel node metastases. The patient received radiotherapy and endrocrine therapy. This case demonstrates that breast cancer may remain stable and not grow for many years. This aspect should be kept in mind by all professionals dealing with women's healthcare, in particular HT users who may develop breast cancer with a less aggressive behavior. Any suspicious finding on mammography, despite being unchanged for a number of years, must be investigated.

Invasive breast cancer: a significant correlation between histological types and molecular subgroups

INTRODUCTION

The special types of breast cancer seem to have not only distinct morphological features but also distinct biological features.

MATERIALS AND METHODS

Women diagnosed with a first primary invasive breast cancer in the 2004-2005 period were identified through Tuscan Cancer Registry. Information on age, tumor size, lymph node status, histological type and grade, hormonal receptors, HER2 immunohistochemical expression were collected. Five subtypes were defined: luminal A, luminal B HER2+, luminal B HER2-, triple negative, and HER2 positive. The association between the histological type and molecular subgroups was assessed by a Fisher's exact test, and a multinomial logistic regression model was used.

RESULTS

Out of 1,487 patients, 34 % were luminal A subtype, 25 % luminal B HER2-, 11 % luminal B HER2+, 19 % triple negative, and 10.2 % HER2+; 58.5 % of cancers were ductal NOS types. With luminal A as reference, histological types distribution was significantly different between the subgroups. Mucinous, tubular, and cribriform histotypes were found among luminal A cancers more than in other subgroups; all medullary carcinomas were triple negative cancers. Pathological stage at diagnosis was more advanced, and histological grade was lower among subgroups other than luminal A.

CONCLUSIONS

Significant association between breast cancer histotypes and molecular subgroups was found.

Heterogeneity of triple-negative breast cancer: histologic subtyping to inform the outcome

BACKGROUND

This study assesses outcome in terms of disease-free survival (DFS) and overall survival (OS) of special types of triple-negative breast cancer (TNBC).

PATIENTS AND METHODS

We identified 8801 women with first primary nonmetastatic breast cancer operated on at the European Institute of Oncology between 1997 and 2005. Of these patients, 781 consecutive patients with immunohistochemically defined TNBC were selected for the analyses. We explored patterns of recurrence by histologic type. Median follow-up was 5.7 years (range 0-13 years).

RESULTS

The 5-year DFS was 77% for TNBC, 68% for human epidermal growth factor receptor 2 (HER2)-positive breast cancer, and 84% and 95% for luminal B and luminal A breast cancer, respectively. From 781 TNBC subtypes, 693 cases (89%) were classified as ductal not otherwise specified (NOS) (invasive ductal carcinoma [IDC]), 29 were classified as apocrine (3.7%), 18 (2.3%) were classified as lobular, 10 (1.2%) were classified as adenoid cystic, and 10 (1.2%) were classified as metaplastic. Five-year DFS and OS were 77% and 84% for patients with ductal carcinoma, 56% and 89% for patients with metaplastic carcinoma, and both 5-year DFS and OS were 100% for patients with adenoid cystic and medullary carcinomas, respectively.

CONCLUSION

Distinct prognostic implications may derive from the specific histotype of TNBC. The identification of these special types has a significant clinical utility and should be considered in therapeutic algorithms.