The diagnosis and management of pre-invasive breast disease: Pathological diagnosis – problems with existing classifications

In this review, we comment on the reasons for disagreement in the concepts, diagnosis and classifications of pre-invasive intraductal proliferations. In view of these disagreements, our proposal is to distinguish epithelial hyperplasia, lobular carcinoma in situ and ductal carcinoma in situ, and to abandon the use of poorly reproducible categories, such as atypical ductal hyperplasia or ductal intraepithelial neoplasia, followed by a number to indicate the degree of proliferation and atypia, as these are not practical for clinical decision making, nor for studies aimed at improving the understanding of breast cancer development. If there is doubt about the classification of an intraductal proliferation, a differential diagnosis and the reason for and degree of uncertainty should be given, rather than categorizing a proliferation as atypical

Gene expression profiling and histopathological characterization of triple-negative/basal-like breast carcinomas

INTRODUCTION: Breast cancer is a heterogeneous group of tumors, and can be subdivided on the basis of histopathological features, genetic alterations and gene-expression profiles. One well-defined subtype of breast cancer is characterized by a lack of HER2 gene amplification and estrogen and progesterone receptor expression ('triple-negative tumors'). We examined the histopathological and gene-expression profile of triple-negative tumors to define subgroups with specific characteristics, including risk of developing distant metastases. METHODS: 97 triple-negative tumors were selected from the fresh-frozen tissue bank of the Netherlands Cancer Institute, and gene-expression profiles were generated using 35K oligonucleotide microarrays. In addition, histopathological and immunohistochemical characterization was performed, and the findings were associated to clinical features. RESULTS : All triple-negative tumors were classified as basal-like tumors on the basis of their overall gene-expression profile. Hierarchical cluster analysis revealed five distinct subgroups of triple-negative breast cancers. Multivariable analysis showed that a large amount of lymphocytic infiltrate (HR = 0.30, 95% CI 0.09-0.96) and absence of central fibrosis in the tumors (HR = 0.14, 95% CI 0.03-0.62) were associated with distant metastasis-free survival. CONCLUSION: Triple-negative tumors are synonymous with basal-like tumors, and can be identified by immunohistochemistry. Based on gene-expression profiling, basal-like tumors are still heterogeneous and can be subdivided into at least five distinct subgroups. The development of distant metastasis in basal-like tumors is associated with the presence of central fibrosis and a small amount of lymphocytic infiltrat

Predicting a local recurrence after breast-conserving therapy by gene expression profiling

INTRODUCTION: To tailor local treatment in breast cancer patients there is a need for predicting ipsilateral recurrences after breast-conserving therapy. After adequate treatment (excision with free margins and radiotherapy), young age and incompletely excised extensive intraductal component are predictors for local recurrence, but many local recurrences can still not be predicted. Here we have used gene expression profiling by microarray analysis to identify gene expression profiles that can help to predict local recurrence in individual patients. METHODS: By using previously established gene expression profiles with proven value in predicting metastasis-free and overall survival (wound-response signature, 70-gene prognosis profile and hypoxia-induced profile) and training towards an optimal prediction of local recurrences in a training series, we establish a classifier for local recurrence after breast-conserving therapy. RESULTS: Validation of the different gene lists shows that the wound-response signature is able to separate patients with a high (29%) or low (5%) risk of a local recurrence at 10 years (sensitivity 87.5%, specificity 75%). In multivariable analysis the classifier is an independent predictor for local recurrence. CONCLUSION: Our findings indicate that gene expression profiling can identify subgroups of patients at increased risk of developing a local recurrence after breast-conserving therapy

Using histopathology breast cancer data to reduce clinical target volume margins at radiotherapy

This study aimed to quantify the incidence and extension of microscopic disease around primary breast tumors in patients undergoing breast-conserving therapy (BCT), focusing on a potential application to reduce radiotherapy boost volumes. An extensive pathology tumor-distribution study was performed using 38 wide local excision specimens of BCT patients. Specimen orientation was recorded and microscopic findings reconstructed to assess the incidence of microscopic disease around the macroscopic tumor. A model of disease spread was built, showing probability of disease extension outside a treated volume (P(out,vol)). The model was applied in 10 new BCT patients. Taking asymmetry of tumor excision into account, new asymmetric margins for the clinical target volume of the boost (CTV(boost)) were evaluated that minimize the volume without increasing P(out,TTV) (TTV being total treated volume: V(surgery) + CTV(boost)). Potential reductions in CTV(boost) and TTV were evaluated. Microscopic disease beyond the tumor boundary occurred isotropically at distances > 1 cm (intended surgical margin) and > 1.5 cm (intended TTV margin) in 53% and 36% of the excision specimens, respectively. In the 10 prospective patients, the average P(out,TTV) was, however, only 16% due to larger surgical margins than intended in some directions. Asymmetric CTV(boost) margins reduced the CTV(boost) and TTV by 27% (20 cc) and 12% (21 cc) on average, without compromising tumor coverage. Microscopic disease extension may occur beyond the current CTV(boost) in approximately one sixth of patients. An asymmetric CTV(boost) that corrects for asymmetry of the surgical excision has the potential to reduce boost volumes while maintaining tumor coverag

Pathological investigation of sentinel lymph nodes

The sentinel lymph-node procedure enables selective targeting of the first draining lymph node, where the initial metastases will form. A negative sentinel node (SN) predicts the absence of tumour metastases in the other regional lymph nodes with high accuracy. This means that in the case of a negative SN, regional lymph-node dissection is no longer necessary. Besides saving costs, this will prevent many side-effects as a result of lymph-node dissection. The task of the pathologist is to screen SNs for metastases. To this end, several techniques are available such as standard histo- and cytopathological techniques, immunohistochemistry, flow cytometry, and molecular biological techniques. These methods are explained and their sensitivity for detecting SN metastases is discussed. Some of these techniques also appear to be useful for intra-operative evaluation of SNs. The standard protocol for detection of SN metastases consists of extensive histopathological investigation including step H and E stained sections and immunohistochemistry. Intra-operative frozen-section analysis of SNs has been shown to be reliable for breast-cancer axillary lymph nodes. In the intra-operative setting, imprint cytology can also be used but its additional value to frozen section analysis is not yet clear. Further studies are necessary to establish the role of sophisticated molecular biological techniques such as reverse transcription polymerase chain reaction (RT-PCR) in detecting SN metastases. The sensitivity of flow cytometry is too low for this purpose