Discrepancies in current practice of pathological evaluation of sentinel lymph nodes in breast cancer. Results of a questionnaire based survey by the European Working Group for Breast Screening Pathology

Diagnostic value of one-step nucleic acid amplification for sentinel lymph node metastasis in cytokeratin 19-positive tumors: evidence from bioinformatics and meta-analysis

Background

The status of the sentinel lymph nodes (SLNs) was an important prognostic factor in varies cancers. A one-step nucleic acid amplification (OSNA) assay, a molecular-based whole-node analysis method based on CK19 mRNA copy number, was developed to diagnose lymph node metastases. We aimed to evaluate the value of OSNA for the diagnosis of sentinel lymph node metastasis in CK19 positive cancers. CK19 mRNA and protein expression for pan-caner analysis were obtained from TCGA and the Human protein atlas database.

Methods

Two researchers independently searched the PubMed, Cochrane Library and Web of Science databases for qualified articles published before December 1, 2023. A meta-analysis was performed using MetaDisc and STATA. Risk bias and quality assessments of the included studies were evaluated, and a subgroup analysis was performed. Ten cancer types were found to be CK19 positively expressed and 7 of 10 had been reported to use OSNA for SLN detection.

Results

After literature review, there were 61 articles included in the meta-analysis, which consisted of 7115 patients with 18007 sentinel lymph nodes. The pooled sensitivity and specificity of OSNA were 0.87 and 0.95 in overall patients. Moreover, we found the background CK19 expression in normal tissue affected the diagnostic accuracy of OSNA. In breast cancer, we performed subgroup analysis. OSNA exhibited to be a stable method across different population groups and various medical centers. In addition, when 250 copies/μl was chosen as the cutoff point of CK19 mRNA, there were a relatively higher sensitivity and AUC in detecting SLN micro-metastasis than 5000 copies/μl.

Discussion

OSNA can predict the occurrence of SLN metastasis accurately in CK19 positive cancers, especially in breast cancer, colorectal cancer, lung cancer, gastric cancer and endometrial cancer. Our study warrants future studies investigating the clinical application of OSNA in pancreatic, ovarian and bladder cancers.

Pragmatic guide to the macroscopic evaluation of breast specimens

The pathological assessment of a breast surgical specimen starts with macroscopic evaluation, arguably one of the most critical steps, as only a small percentage of the tissue is examined microscopically. To properly evaluate and select tissue sections from breast specimens, it is essential to correlate radiological findings, prior biopsies, procedures and treatment with the gross findings. Owing to its fatty nature, breast tissue requires special attention for proper fixation to ensure appropriate microscopic evaluation and performance of ancillary studies. In addition, knowledge of the information necessary for patient management will ensure that these data are collected during the macroscopic evaluation, and appropriate sections are taken to obtain the information needed from the microscopic evaluation. Herein, we present a review of the macroscopic evaluation of different breast specimen types, including processing requirements, challenges and recommendations.

Accuracy of Intraoperative Frozen Section Analysis of Lymph Nodes in Women Undergoing Axillary Sampling for Treatment of Breast Cancer: Single Institution Audit

BACKGROUND

Axillary lymph node (LN) positivity is an important prognostic factor in breast cancer. Almost 30% clinically node negative (cN0) early breast cancers have positive nodes on pathology, wherein an axillary dissection is done as a second stage surgery. Intra operative frozen section (FS) potentially avoids redo surgery.

MATERIALS AND METHODS

We performed a retrospective audit for the false negative rate of intraoperative FS, from 2014 to 2018. All cN0 women undergoing upfront surgery, who underwent low axillary sampling (LAS) with FS were included.

RESULTS

Of 22,854 breast cancer cases, 2230 underwent LAS, of which 877 were node positive. Intraoperative FS was negative in 1423/2230 (63.81%) cases, of which 71/1423 (4.98%) were false negative, and came positive on final histopathology report (HPR). These 71 women had a median of 5 nodes (mean 4.85) dissected on FS (range 1-12) with a median 1 (mean 1.3) node positive (range 1-6) on HPR. The sensitivity of FS was 91.89% (95% CI, 89.89-93.62), with a negative predictive value of 95.01% (95% CI, 93.84-95.97), accuracy of 96.73% (95% CI, 95.90-97.43) and false negative rate 4.98%. On logistic regression analysis, micrometastasis (Odds ratio (OR) 7.76, 95% CI, 3.49-17.25, P < .001) lobular histology (OR 2.50, 95% CI, 1.007-6.223, P = .04) and nodes dissected (OR 1.18, 95% CI, 1.07-1.30, P = .001) were associated with higher false negative FS, and extra nodal extension (OR 0.32, 95% CI, 0.18-0.57, P ≤ .001) with lower false negative FS.

CONCLUSION

The high concordance between intraoperative FS and definitive histology, suggests it's routine use for Sentinel lymph node/LAS LN can help avoid a second surgery.

Uncertainties and controversies in axillary management of patients with breast cancer

The aims of this Oncoplastic Breast Consortium and European Breast Cancer Research Association of Surgical Trialists initiative were to identify uncertainties and controversies in axillary management of early breast cancer and to recommend appropriate strategies to address them. By use of Delphi methods, 15 questions were prioritized by more than 250 breast surgeons, patient advocates and radiation oncologists from 60 countries. Subsequently, a global virtual consensus panel considered available data, ongoing studies and resource utilization. It agreed that research should no longer be prioritized for standardization of axillary imaging, de-escalation of axillary surgery in node-positive cancer and risk evaluation of modern surgery and radiotherapy. Instead, expert consensus recommendations for clinical practice should be based on current evidence and updated once results from ongoing studies become available. Research on de-escalation of radiotherapy and identification of the most relevant endpoints in axillary management should encompass a meta-analysis to identify knowledge gaps, followed by a Delphi process to prioritize and a consensus conference to refine recommendations for specific trial designs. Finally, treatment of residual nodal disease after surgery was recommended to be assessed in a prospective register.

MEAI: an artificial intelligence platform for predicting distant and lymph node metastases directly from primary breast cancer

PURPOSE

Breast cancer patients typically have decent prognoses, with a 5-year survival rate of more than 90%, but when the disease metastases to lymph node or distant, the prognosis drastically declines. Therefore, it is essential for future treatment and patient survival to quickly and accurately identify tumor metastasis in patients. An artificial intelligence system was developed to recognize lymph node and distant tumor metastases on whole-slide images (WSIs) of primary breast cancer.

METHODS

In this study, a total of 832 WSIs from 520 patients without tumor metastases and 312 patients with breast cancer metastases (including lymph node, bone, lung, liver, and other) were gathered. Based on the WSIs were randomly divided into the training and testing cohorts, a brand-new artificial intelligence system called MEAI was built to identify lymph node and distant metastases in primary breast cancer.

RESULTS

The final AI system attained an area under the receiver operating characteristic curve of 0.934 in a test set of 187 patients. In addition, the potential for AI system to increase the precision, consistency, and effectiveness of tumor metastasis detection in patients with breast cancer was highlighted by the AI's achievement of an AUROC higher than the average of six board-certified pathologists (AUROC 0.811) in a retrospective pathologist evaluation.

CONCLUSION

The proposed MEAI system can provide a non-invasive approach to assess the metastatic probability of patients with primary breast cancer.

Reporting of Surgically Removed Lymph Nodes for Breast Tumors: Recommendations From the International Collaboration on Cancer Reporting

CONTEXT.—

The International Collaboration on Cancer Reporting (ICCR), supported by major pathology and cancer organizations, aims at the standardization of evidence-based pathology reporting of different types of cancers, with the inclusion of all parameters deemed to be relevant for best patient care and future data collection. Lymph node metastasis is one of the most important prognostic factors in breast cancer.

OBJECTIVE.—

To produce a histopathology reporting guide by a panel of recognized experts from the fields of pathology and surgery with elements deemed to be core (required) and noncore (recommended) to report when assessing regional lymph nodes of patients with breast cancer.

DATA SOURCES.—

Published literature, previous guidelines/recommendations, and current cancer staging principles were the basis of the data set drafted by the expert panel. This was discussed in a series of teleconferences and email communications. The draft data set was then made available for public consultation through the ICCR Web site. After this consultation and ICCR ratification, the data set was finalized.

CONCLUSIONS.—

The ICCR has published a data set for the reporting of surgically removed lymph nodes (including sentinel lymph node biopsy, axillary lymph node dissection, targeted axillary surgery, and lymph node sampling specimens) for breast tumors. This is part of a series of 4 ICCR breast cancer-related data sets. It includes 10 core elements along with 2 noncore elements. This should allow for synoptic reporting, which is more precise, uniform, and complete than nonsynoptic reporting, and leads to improved patient outcomes.

The diagnostic accuracy of intraoperative frozen section biopsy for diagnosis of sentinel lymph node metastasis in breast cancer patients: a meta-analysis

Sentinel lymph node (SLN) sampling is important for evaluating the nodal stage of breast cancer when the axillary nodes are clinically free of metastasis. The intraoperative frozen section (IFS) of SLN is used for lymph node assessment. This meta-analysis aims to provide evidence about the diagnostic accuracy and the applicability of IFS of SLN in breast cancer patients. Data were collected by searching PubMed, Cochrane, Scopus, and Web of Science electronic databases for trials matching our eligibility criteria. The statistical analysis included the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and pooled studies' diagnostic odds ratio outcomes. The analyses were conducted using the Open Meta-analyst software. This meta-analysis pooled the results of 110 studies. The overall sensitivity of IFS for SLN metastasis was 74.7%; 95% CI [72.0, 77.2], P < 0.001. It was 31.4% 95% CI [25.2, 38.3], P < 0.001 for the micro-metastasis, and 90.2%; 95% CI [86.5, 93.0], P < 0.001 for the macro-metastasis. The overall specificity was 99.4%; 95% CI [99.2, 99.6], P < 0.001. The overall positive likelihood ratio was 121.4; 95% CI [87.9, 167.6], P < 0.001, and the overall negative likelihood ratio was 0.226; 95% CI [0.186, 0.274], P < 0.001. The overall diagnostic odds ratio of IFS for diagnosing SLN metastasis was 569.5; 95% CI [404.2, 802.4], P < 0.001. The intraoperative frozen section of SLN has good sensitivity for diagnosing breast cancer macro-metastasis. However, the sensitivity is low for micro-metastasis. The specificity is very satisfactory.

Sentinel lymph node assessment in breast cancer-an update on current recommendations

Sentinel lymph node biopsy (SLNB) has become the preferred method of surgical pathological nodal staging of early breast cancer by the end of the nineties. As the most likely sites of metastasis, the SLNs allow a more precise staging, and indeed gross sectioning, step sectioning, immunohistochemistry, and molecular staging methods have been used to disclose metastatic involvement of these lymph nodes. This review summarizes the backgrounds of SLNB, trends in related surgery and pathology. It also gives an insight into European National recommendations related to SLN and divergent daily practices in European pathology departments, on the basis of replies to questionnaires from 84 pathologists from 38 European countries. The questionnaires revealed the post-neoadjuvant setting as an area where a significant minority of pathologists report less confidence in classifying residual nodal involvement into TNM categories. The review also summarizes the neoadjuvant therapy-related aspects of SLNB.

X-ray microtomosynthesis of unstained pathology tissue samples

In pathology protocols, a tissue block, such as one containing a mouse brain or a biopsy sample from a patient, can produce several hundred thin sections. Substantial time may be required to analyse all sections. In cases of uncertainty regarding which sections to focus on, noninvasive scout imaging of intact blocks can help in guiding the pathology procedure. The scouting step is ideally done in a time window of minutes without special sample preparation that may interfere with the pathology procedures. The challenge is to obtain some visibility of unstained tissue structures at sub‐10 µm resolution.

We explored a novel x‐ray tomosynthesis method as a way to maximise contrast‐to‐noise ratio, a determinant of tissue visibility. It provided a z‐stack of thousands of images at 7.3 μm resolution (10% contrast, half‐period of 68.5 line pairs/mm), in scans of 5‐15 minutes. When compared with micro‐CT scans, the straight‐line tomosynthesis scan did not need to rotate the sample, which allowed flat samples, such as paraffin blocks, to be kept as close as possible to the x‐ray source. Thus, given the same hardware, scan time and resolution, this mode maximised the photon flux density through the sample, which helped in maximising the contrast‐to‐noise ratio. The tradeoff of tomosynthesis is incomplete 3D information.

The microtomosynthesis scanner has scanned 110 unstained human and animal tissue samples as part of their respective pathology protocols. In all cases, the z‐stack of images showed tissue structures that guided sectioning or provided correlative structural information. We describe six examples that presented different levels of visibility of soft tissue structures. Additionally, in a set of coronary artery samples from an HIV patient donor, microtomosynthesis made a new discovery of isolated focal calcification in the internal elastic lamina of coronary wall, which was the onset of medial calcific sclerosis in the arteries.

Axillary staging based on molecular analysis: Results of the B-CLOSER-II study

INTRODUCTION

Axillary staging (pN) is a strong predictor of outcome in early stage breast cancer yet following the publication of the Z0011 trial there has been an increasing tendency to spare lymph node dissection. Automated molecular detection of cytokeratin 19mRNA by one-step nucleic acid amplification (OSNA) has been demonstrated to be an accurate method to assess sentinel lymph node (SLN) metastasis. In this study we compare histological and molecular methods following complete axillary lymph node dissection (cALND), determine whether molecular axillary staging affects survival, and evaluate the predictive and prognostic value of total tumor load in ALND (AD-TTL) and in all positive nodes (G-TTL).

MATERIAL AND METHODS

Axillary lymph nodes were collected from 102 patients with primary breast cancer with histological confirmation of axillary involvement (cN+) or positive SLN. The central 1-mm portion of each non-SLN was processed for hematoxylin-eosin staining and the remaining tissue was analyzed by OSNA.

RESULTS

Non-SLNs were diagnosed as positive in 72 out of 102 patients (70.6 %) on OSNA compared with only 53 (52 %) on histology (p < 0.01). Thirteen patients would have changed staging if the diagnoses provided had been by molecular methods (p < 0.01), but without a change in prognosis. AD-TTL and G-TTL were predictive of recurrence and mortality.

CONCLUSIONS

Compared to molecular detection, histological examination significantly underestimates the frequency of axillary node metastases. However, the increase in pN did not show a clinical effect on survival in those patients.

[Pathological process for sentinel lymph node]

Sentinel node is defined as the first node to receive drainage from a primary tumor and seems to reflect the nodal status in the lymphatic drainage of the tumor. Sentinel node technique has modified the pathological examination of lymph nodes, with intraoperative evaluation of sentinel node, allowing immediate lymph node dissection in case of positive sentinel node, and histological ultrastratification to detect occult metastases. This is a literature review of different histological protocols of sentinel node according to different organs. Except for sentinel node in breast cancer and melanoma, intraoperative examination of sentinel node is helpful using frozen section, more sensitive than touch imprint cytology. Sentinel node should be embedded in paraffin block entirely after gross sectioning at two millimeters intervals parallel to the long axis of the node. Histological ultrastaging with serial sections can be helpful, but the number of sections and the interval between them is not codified. Three sections at 200-250 microns can identify the majority of micrometastases (<2mm and >200 microns). Systematic immunohistochemistry of sentinel node is not necessary for breast cancers, since isolated tumor cells do not modify the therapeutic strategy, but remains useful in other organs.

Correlative Detection of Isolated Single and Multi-Cellular Calcifications in the Internal Elastic Lamina of Human Coronary Artery Samples

Histopathology protocols often require sectioning and processing of numerous microscopy slides to survey a sample. Trade-offs between workload and sampling density means that small features can be missed. Aiming to reduce the workload of routine histology protocols and the concern over missed pathology in skipped sections, we developed a prototype x-ray tomographic scanner dedicated to rapid scouting and identification of regions of interest in pathology specimens, thereby allowing targeted histopathology analysis to replace blanket searches. In coronary artery samples of a deceased HIV patient, the scanner, called Tomopath, obtained depth-resolved cross-sectional images at 15 µm resolution in a 15-minute scan, which guided the subsequent histological sectioning and microscopy. When compared to a commercial tabletop micro-CT scanner, the prototype provided several-fold contrast-to-noise ratio in 1/11^th the scan time. Correlated tomographic and histological images revealed two types of micro calcifications: scattered loose calcifications typically found in atherosclerotic lesions; isolated focal calcifications in one or several cells in the internal elastic lamina and occasionally in the tunica media, which we speculate were the initiation of medial calcification linked to kidney disease, but rarely detected at this early stage due to their similarity to particle contaminants introduced during histological processing, if not for the evidence from the tomography scan prior to sectioning. Thus, in addition to its utility as a scouting tool, in this study it provided complementary information to histological microscopy. Overall, the prototype scanner represents a step toward a dedicated scouting and complementary imaging tool for routine use in pathology labs.

Sentinel Node Biopsy in Early Breast Cancer: Lessons Learned from More than 1000 Cases at a Single Institution

Aims

The aims of this paper are to report the development of sentinel node biopsy (SNB) in breast cancer at a single institution and to discuss the relevant issues on SNB still to be elucidated.

Patients and methods

From 1998 to 2010, 1021 SNBs with frozen section examination were carried out in patients with breast cancer. In the early period (1998–2002) SNB was always combined with axillary lymph node dissection (ALND). From 2002 onwards, only patients with a positive SNB result underwent ALND (late period). The characteristics of patients with infiltrating carcinoma (IC) and ductal carcinoma in situ (DCIS) and the histological status of the sentinel nodes were examined. The survival outcomes of node-negative patients were compared between patients submitted to SNB and ALND (ALND group) during the early period and patients who underwent only SNB during the late period (SNB group).

Results

The sentinel node was identified intraoperatively in 98.3% of cases. During the early period the overall accuracy of SNB was 97.0%. During the late period, 700 patients with IC and 140 with DCIS underwent SNB. In the IC group, 149 patients (21.3%) had sentinel node macrometastases and 36 (5.1%) micrometastases; of that subgroup, 21 underwent ALND and no other metastatic lymph nodes were found, and 15 underwent SNB only. Axillary recurrences were observed in 4 patients (0.77%) with negative SNB; none of these were among the patients with micrometastatic SNB. Two patients (1.4%) with DCIS had a positive SNB. In node-negative patients the 5-year overall survival was 96.7% in the ALND group and 96.5% in the SNB group (P = 0.63). The 5-year disease-free survival was 93.8% and 93.2% in the ALND and SNB groups, respectively (P = 0.77).

Conclusions

Overall and disease-free survival in patients with a negative SNB result and no further axillary surgery were equal to those in patients with negative ALND. Intraoperative assessment of the sentinel node in expert hands has a low false-negative rate and allows immediate ALND in patients with sentinel node metastases, avoiding the need for a second operation. ALND for sentinel node micrometastases may be safely omitted in most patients with early stage breast cancer.

A multicentre validation of Metasin: a molecular assay for the intraoperative assessment of sentinel lymph nodes from breast cancer patients

AIMS

Treatment strategies for breast cancer continue to evolve. No uniformity exists in the UK for the management of node-positive breast cancer patients. Most centres continue to use conventional histopathology of sampled sentinel lymph nodes (SLNs), which requires delayed axillary clearance in up to 25% of patients. Some use touch imprint cytology or frozen section for intraoperative testing, although both have inherent sensitivity issues. An intraoperative molecular diagnostic approach helps to overcome some of these limitations. The aim of this study was to assess the clinical effectiveness of Metasin, a molecular method for the intraoperative evaluation of SLNs.

METHODS AND RESULTS

RNA from 3296 lymph nodes from 1836 patients undergoing SLN assessment was analysed with Metasin. Alternate slices of tissue were examined in parallel by histology. Cases deemed to be discordant were analysed by protein gel electrophoresis. There was concordance between Metasin and histology in 94.1% of cases, with a sensitivity of 92% [95% confidence interval (CI) 88-94%] and a specificity of 97% (95% CI 95-97%). Positive and negative predictive values were 88% and 98%, respectively. Over half of the discordant cases (4.4%) were ascribed to tissue allocation bias (TAB).

CONCLUSIONS

Clinical validation of the Metasin assay suggests that it is sufficiently sensitive and specific to make it fit for purpose in the intraoperative setting.

Intraoperative Frozen Section Evaluation of Sentinel Lymph Nodes in Breast Carcinoma: Single-Institution Indian Experience

Sentinel lymph node biopsy is an established way of predicting axillary nodal metastasis in early breast cancer. Intraoperative frozen sections (FS) of sentinel lymph nodes (SLNs) can be used to detect metastatic disease, allowing immediate axillary lymph node dissection. The purpose of this study was to evaluate the accuracy of intraoperative frozen sections in evaluation of sentinel lymph nodes in cases of breast cancer. Between March 2006 and August 2010, a total of 164 patients with clinically node-negative operable breast cancer were subjected to sentinel lymph node biopsy of axillary lymph nodes using preoperative peritumoral injection of radioactive colloid and methylene blue. Intraoperative identification of sentinel nodes was done using a handheld gamma probe and identification of blue-stained nodes. The nodes were sent for frozen section examination. The results of frozen section were compared with the final histopathology. Out of the 164 cases, metastases were detected in SLN by frozen section in 38 cases. There were three false-negative cases (all showing micrometastasis on final histopathology). FS had sensitivity of 92.6 %, specificity of 100 %, and overall accuracy of 98.1 %. The positive predictive value was 100 %, and the negative predictive value was 97.6 %. FS for diagnosis of metastasis of SLNs is reliable. Patients with negative SLNs by the FS diagnosis can avoid reoperation for axillary lymph node dissection. However, FS may fail to detect micrometastases, especially in cases with small tumors.

Assessment of Sentinel Node Biopsies With Full-Field Optical Coherence Tomography

Current techniques for the intraoperative analysis of sentinel lymph nodes during breast cancer surgery present drawbacks such as time and tissue consumption. Full-field optical coherence tomography is a novel noninvasive, high-resolution, fast imaging technique. This study investigated the use of full-field optical coherence tomography as an alternative technique for the intraoperative analysis of sentinel lymph nodes. Seventy-one axillary lymph nodes from 38 patients at Tenon Hospital were imaged minutes after excision with full-field optical coherence tomography in the pathology laboratory, before being handled for histological analysis. A pathologist performed a blind diagnosis (benign/malignant), based on the full-field optical coherence tomography images alone, which resulted in a sensitivity of 92% and a specificity of 83% (n = 65 samples). Regular feedback was given during the blind diagnosis, with thorough analysis of the images, such that features of normal and suspect nodes were identified in the images and compared with histology. A nonmedically trained imaging expert also performed a blind diagnosis aided by the reading criteria defined by the pathologist, which resulted in 85% sensitivity and 90% specificity (n = 71 samples). The number of false positives of the pathologist was reduced by 3 in a second blind reading a few months later. These results indicate that following adequate training, full-field optical coherence tomography can be an effective noninvasive diagnostic tool for extemporaneous sentinel node biopsy qualification.

An intra-operative RT-LAMP method allows rapid and reliable detection of sentinel lymph node metastasis in breast cancer patients

The rapid determination of metastasis in sentinel lymph nodes (SLNs) of breast cancer patients plays a significant role in the selection of a surgery strategy. Although a previous one-step nucleic acid amplification assay that uses reverse-transcription (RT) loop-mediated isothermal amplification (LAMP) has showed specific advantages over traditional pathological examination, its target marker requires optimisation. In addition to epithelial-specific CK19, the internal control gene PBGD and the breast-specific PIP were included in the new method. After the RT-LAMP primers were designed and verified using a cell line, the performance of our method was evaluated by comparing it with the corresponding result of the Food and Drug Administration approved breast lymph node (BLN) assay and routine pathological examination. One hundred and seventy-four valid SLN samples from 101 patients were collected from five hospitals. The threshold of reaction time for CK19, PIP and PBGD was defined as 16, 20 and 20 min, respectively. Compared with the BLN assay, the concordance rate of our method was 95.4% (166/174). Statistical analysis revealed that the two methods are consistent (kappa = 0.890, P < 0.001). When compared with pathological examination, the performance of our method (sensitivity = 81.3%, specificity = 89.7%, kappa = 0.691, P < 0.001) was similar to that of the BLN assay (sensitivity = 87.5%, specificity = 84.9%, kappa = 0.668, P < 0.001). This result demonstrates the potential usefulness of our method in clinical practice. In conclusion, we preliminarily established an intra-operative diagnostic method that assimilates the merits of previous assays. In contrast with the BLN assay and pathological examination, our method can be completed in 30 min and shows high sensitivity, specificity and consistency, which we consider as promising for clinical application.

Evolution of sentinel lymph node biopsy in breast cancer, in and out of vogue?

Sentinel lymph node biopsy (SLNB) was introduced 2 decades ago and thereafter validated for routine surgical management of breast cancer, including cases treated with neoadjuvant chemotherapy. As the number of lymph nodes for staging has decreased, pathologists have scrutinized SLN with a combination of standard hematoxylin and eosin, levels, immunohistochemistry (IHC), and molecular methods. An epidemic of small-volume metastases thereby arose, leading to modifications in the American Joint Committee on Cancer staging to accommodate findings such as isolated tumor cells (ITC) and micrometastases. With the goal of determining the significance of these findings, retrospective followed by prospective trials were performed, showing mixed results. The ACOSOG Z10 and NSABP B-32 trials both independently showed that ITC and micrometastases were not significant and thus discouraged the use of levels and IHC for detecting them. However, the Surveillance Epidemiology and End Results database showed that patients with micrometastases had an overall decreased survival. In addition, the MIRROR (Micrometastases and ITC: Relevant and Robust or Rubbish?) trial, showed that patients with ITC and micrometastases treated with adjuvant therapy had lower hazard ratios compared with untreated patients. Subsequently, the ACOSOG Z0011 trial randomized patients with up to 2 positive SLN to axillary lymph node dissection (ALND) or not, all treated with radiation and chemotherapy, showing no difference in survival or recurrence rates between the 2 groups and causing a shift from ALND. As the rate of ALND has declined, the necessity of performing levels, IHC, frozen section, and molecular studies on SLN needs to be revisited.

Treatment of sentinel node-positive breast cancer

Sentinel node biopsy has become well accepted as a minimally invasive means of accurately staging the axilla in breast cancer patients. Patients with metastases in the sentinel node(s) have traditionally proceeded to completion of axillary node dissection, whereas patients who are node negative can be spared the morbidity of this procedure. Recently, there has been some debate as to what constitutes node-positive disease and whether patients with metastasis in the sentinel node(s) require completion axillary dissection. This review addresses the controversies regarding the management of sentinel node-positive breast cancer patients.

The Ever-Changing Role of Sentinel Lymph Node Biopsy in the Management of Breast Cancer

Context.—Axillary nodal status remains one of the most important prognostic indicators in the management of breast cancer. Axillary node metastases are seen in fewer than half of breast cancer cases, and axillary lymph node dissection is associated with significant morbidity. Sentinel lymph node biopsy (SLNB) has become the gold standard for axillary staging of breast cancer.

Objective.—To present a detailed review of the existing studies on SLNB in relation to the various techniques, the pathologic evaluation of the sentinel node, and special situations that can involve SLNB. We discuss recent trials that have already had an influence on surgical and pathologic management of breast cancer. In this article, we also discuss our practice and experience at UMass Memorial Medical Center, Worcester, Massachusetts, from a pathologic and surgical perspective.

Data Sources.—Published articles from peer-reviewed journals in PubMed (US National Library of Medicine).

Conclusions.—Sentinel node biopsy has become standard of care in the surgical management of breast cancer, and emerging data show that the survival benefits of axillary lymph node dissection may not be greater than sentinel node biopsy alone in patients with up to 2 positive sentinel nodes. Therefore, there have been recent changes to the role of intraoperative sentinel node evaluation, and an impact on overall breast cancer management.

[Diagnostic validity of the intraoperative analysis in frozen section of the sentinel lymph node in the surgical management of breast cancer]

OBJECTIVE

The method for intraoperative sentinel lymph node (SLN) evaluation has still not been established in breast cancer staging. This study has evaluated the diagnostic validity and impact of intraoperative analysis using the frozen section (FS) of SLN.

MATERIAL AND METHODS

We performed a descriptive study of the diagnostic validity of the FS of the SLN in patients with breast cancer and selective sentinel node biopsy (SSNB) from October-2006 to October-2012. The diagnostic validity indexes were evaluated using sensitivity, specificity, positive and negative predictive values and global value. Gold standard was considered as the final histopathological results of the biopsies.

RESULTS

A total of 370 patients were studied. Sensitivity and specificity for detection of metastasis by FS in the SLN were 67% and 100%, respectively. Global diagnostic validity was 95%. There was a correlation between detection of metastasis and tumor size (p<0.05). Twelve of the 15 patients with SLN micro-metastases underwent axillary lymph node dissection (ALND). Metastatic lymph nodes were not found in any of them.

CONCLUSIONS

Intraoperative FS examination of the SLN is a useful and reliable predictor of axillary lymph node staging in patients with initial stages of breast cancer. FS reduces the need for second interventions, at least for most patients who have breast cancer with identifiable positive SLN and unequivocal evidence of positive lymph node disease.

Molecular detection of lymph node metastasis in breast cancer patients treated with preoperative systemic chemotherapy: a prospective multicentre trial using the one-step nucleic acid amplification assay

BACKGROUND

For patients with breast cancer treated with preoperative chemotherapy, residual tumour burden in lymph nodes is the strongest prognostic factor. However, conventional pathological examination has limitations that hinder the accurate and reproducible measurement. The one-step nucleic acid amplification (OSNA) assay is a novel molecular method for detecting nodal metastasis. In this prospective multicentre trial, we assessed the performance of the OSNA assay in detecting nodal metastasis after chemotherapy.

METHODS

In total, 302 lymph nodes from 80 breast cancer patients who underwent axillary dissection after chemotherapy were analysed. Each node was cut into two or four slices. One piece or alternate pieces were evaluated by pathology, and the other(s) were examined using the OSNA assay. The results of the two methods were compared. Stromal fibrosis, histiocytic aggregates, and degenerated cancer cells were regarded as chemotherapy-induced histological changes.

RESULTS

The overall accuracy, sensitivity, and specificity of the OSNA assay compared with the reference pathology were 91.1%, 88.3%, and 91.7%, respectively. Of the 302 lymph nodes, 66 (21.9%) exhibited chemotherapy-induced histology. For these nodes, the accuracy, sensitivity, and specificity were 90.9%, 88.9%, and 93.3%, respectively.

CONCLUSION

The OSNA assay can detect the residual tumour burden as accurately as conventional pathology, although chemotherapy-induced histological changes are present.

Multiple Step-section Frozen Section sentinel lymph node biopsy--a review of 717 patients

Sentinel Lymph Node Biopsy (SLNB) is the standard of care for axillary staging in breast cancer. Multiple Step-section Frozen Section (MSFS) analysis is used in our institution for SLNB. This is performed intra-operatively by freezing sentinel lymph nodes to obtain multiple step-sections which are examined histologically for evidence of metastases. Patients whose sentinel lymph nodes contained macrometastases proceeded to an axillary node clearance during the same operation. 717 patients over a two and a half year period had MSFS analysis. With regards to macrometastases, MSFS analysis had a sensitivity of 93.8%, a specificity of 99.3%, a positive-predictive value of 97.4% and a negative-predictive value of 98.2%. MSFS analysis of sentinel lymph nodes is a safe and accurate procedure. It is a relatively cost-effective alternative to molecular technologies relying on DNA amplification and more accurate than standard frozen section or touch-prep cytology.

Three-dimensional quantitative ultrasound for detecting lymph node metastases

PURPOSE

Detection of metastases in lymph nodes (LNs) is critical for cancer management. Conventional histological methods may miss metastatic foci. To date, no practical means of evaluating the entire LN volume exists. The aim of this study was to develop fast, reliable, operator-independent, high-frequency, quantitative ultrasound (QUS) methods for evaluating LNs over their entire volume to effectively detect LN metastases.

METHODS

We scanned freshly excised LNs at 26 MHz and digitally acquired echo-signal data over the entire three-dimensional (3D) volume. A total of 146 LNs of colorectal, 26 LNs of gastric, and 118 LNs of breast cancer patients were enrolled. We step-sectioned LNs at 50-μm intervals and later compared them with 13 QUS estimates associated with tissue microstructure. Linear-discriminant analysis classified LNs as metastatic or nonmetastatic, and we computed areas (Az) under receiver-operator characteristic curves to assess classification performance. The QUS estimates and cancer probability values derived from discriminant analysis were depicted in 3D images for comparison with 3D histology.

RESULTS

Of 146 LNs of colorectal cancer patients, 23 were metastatic; Az = 0.952 ± 0.021 (95% confidence interval [CI]: 0.911-0.993); sensitivity = 91.3% (specificity = 87.0%); and sensitivity = 100% (specificity = 67.5%). Of 26 LNs of gastric cancer patients, five were metastatic; Az = 0.962 ± 0.039 (95% CI: 0.807-1.000); sensitivity = 100% (specificity = 95.3%). A total of 17 of 118 LNs of breast cancer patients were metastatic; Az = 0.833 ± 0.047 (95% CI: 0.741-0.926); sensitivity = 88.2% (specificity = 62.5%); sensitivity = 100% (specificity = 50.5%). 3D cancer probability images showed good correlation with 3D histology.

CONCLUSIONS

These results suggest that operator- and system-independent QUS methods allow reliable entire-volume LN evaluation for detecting metastases. 3D cancer probability images can help pathologists identify metastatic foci that could be missed using conventional methods.

Pathological controversies in breast cancer: classification of ductal carcinoma in situ, sentinel lymph nodes and low volume metastatic disease and reporting of neoadjuvant chemotherapy specimens

The pathological classification of breast cancer is constantly being updated to reflect the advances in our clinical and biological understanding of the disease. This overview examines new insights into the classification and molecular biology of ductal carcinoma in situ, the pathological handling of sentinel lymph node biopsies and the identification of low volume disease (micrometastases and isolated tumour cells) and the handling and reporting of specimens after neoadjuvant therapy. The molecular subtypes of invasive breast cancer are also represented in ductal carcinoma in situ. It is hoped that alongside traditional histological features, such as cytological grade and the presence of necrosis, this will lead to better classification systems with improved prediction of clinical behaviour, in particular the risk of progression to invasive cancer, and enable more targeted management. Sentinel lymph node biopsy is now the standard of care for early stage breast cancer in clinically node-negative patients. However, the handling and reporting of these specimens remains controversial, largely related to the uncertainties regarding the clinical significance of micrometastases and isolated tumour cells. The increasing use of neoadjuvant therapies has introduced challenges for the pathologist in the handling and interpretation of these specimens. Grading the tumour response, particularly the identification of a complete pathological response, is prognostically important. However, there is still marked variability in reporting these specimens in routine practice, and consensus guidelines for the histopathology reporting of breast cancers after neoadjuvant chemotherapy based on robust, validated evidence are presently lacking.

Predicting sentinel lymph node metastasis in a Chinese breast cancer population: assessment of an existing nomogram and a new predictive nomogram

We assessed the MSKCC nomogram performance in predicting SLN metastases in a Chinese breast cancer population. A new model (the SCH nomogram) was developed with clinically relevant variables and possible advantages. Data were collected from 1,545 patients who had a successful SLN biopsy between March 2005 and November 2011. We validated the MSKCC nomogram in the modeling and validation group. Clinical and pathologic features of SLN biopsy in modeling group of 1,000 patients were assessed with multivariable logistic regression to predict the presence of SLN metastasis in breast cancer. The SCH nomogram was created from the logistic regression model and subsequently applied to 545 consecutive SLN biopsies. By multivariate analysis, age, tumor size, tumor location, tumor type, and lymphovascular invasion were identified as independent predictors of SLN metastasis. The SCH nomogram was then developed using the five variables. The new model was accurate and discriminating (with an AUC of 0.7649 in the modeling group) compared to the MSKCC nomogram (with an AUC of 0.7105 in the modeling group). The area under the ROC curve for the SCH nomogram in the validation population is 0.7587. The actual probability trends for the various deciles were comparable to the predicted probabilities. The false-negative rates of the SCH nomogram were 1.67, 3.54, and 8.20 % for the predicted probability cut-off points of 5, 10, and 15 %, respectively. Compared with the MSKCC nomogram, the SCH nomogram has a better AUC with fewer variables and has lower false-negative rates for the low-probability subgroups. The SCH nomogram could serve as a more acceptable clinical tool in preoperative discussions with patients, especially very-low-risk patients. When applied to these patients, the SCH nomogram could be used to safely avoid a SLN procedure. The nomogram should be validated in various patient populations to demonstrate its reproducibility.

Implementation of step sectioning in the examination of sentinel lymph nodes to improve the detection of micrometastases in breast cancer patients

The object of this study was to examine whether a new protocol for examination of sentinel lymph nodes (SLNs) would lead to the detection of more metastases. Sections of 1 mm would identify most SLN macrometastases, and step sections at intervals of 200-250 μm would identify most micrometastases. A total of 111 breast cancer patients who underwent the SLN procedure at St. Olavs University Hospital in Trondheim, Norway in 2008 were included in the study group. Their SLNs were processed according to a new standardized protocol with sections of 2-3 mm being step sectioned at intervals of 200-250 μm. A total of 109 breast cancer patients undergoing the SLN procedure in 2007 were used as a reference group. Metastases were found in 29% of the cases, compared with 26% in the reference group. Step sectioning of SLNs revealed metastases in five cases initially found to be negative. The metastases of the study group were smaller, with a median value of 1.25 mm compared with 4.25 mm in the reference group. Step sectioning led to the detection of metastases in SLNs initially found to be negative. The median size of the metastases was considerably smaller in the study group than in the reference group.

Breast cancer sentinel lymph node and axillary lymphadenectomy: new tools for new challenges

Axillary lymph node status at the time of diagnosis is the most important prognostic indicator for women with breast cancer, and may influence management decisions. However, at present its role is controversial, as some groups recommend avoiding axillary lymph node dissection (ALND) in cases with metastasis of any size in the sentinel lymph nodes. Molecular analysis allows full examination of the sentinel lymph nodes in a short time period, discriminatation between macrometastasis, micrometastasis and isolated tumor cells, and helps to predict the performance of ALND. ALND may be the treatment of choice in some patients, even in cases of low-volume metastasis, as chemotherapy does not control regional disease well. In addition, the collection of metastatic cells, as well as the local immune surveillance, is susceptible to further molecular studies that will offer prognostic and predictive information, which may have an impact on therapeutic decisions, so that individualized treatments can be adequately designed.

High risk of non-sentinel node metastases in a group of breast cancer patients with micrometastases in the sentinel node

Axillary lymph node dissection (ALND) in breast cancer patients with positive sentinel nodes is under debate. We aimed to establish two models to predict non-sentinel node (NSN) metastases in patients with micrometastases or isolated tumor cells (ITC) in sentinel nodes, to guide the decision for ALND. A total of 1,577 breast cancer patients with micrometastases and 304 with ITC in sentinel nodes, treated by sentinel lymph node dissection and ALND in 2002-2008 were identified in the Danish Breast Cancer Cooperative Group database. Risk of NSN metastases was calculated according to clinicopathological variables in a logistic regression analysis. We identified tumor size, proportion of positive sentinel nodes, lymphovascular invasion, hormone receptor status and location of tumor in upper lateral quadrant of the breast as risk factors for NSN metastases in patients with micrometastases. A model based on these risk factors identified 5% of patients with a risk of NSN metastases on nearly 40%. The model was however unable to identify a subgroup of patients with a very low risk of NSN metastases. Among patients with ITC, we identified tumor size, age and proportion of positive sentinel nodes as risk factors. A model based on these risk factors identified 32% of patients with risk of NSN metastases on only 2%. Omission of ALND would be acceptable in this group of patients. In contrast, ALND may still be beneficial in the subgroup of patients with micrometastases and a high risk of NSN metastases.

Reliability of whole sentinel lymph node analysis by one-step nucleic acid amplification for intraoperative diagnosis of breast cancer metastases

OBJECTIVE

To assess the reliability of using the One-Step Nucleic Acid Amplification (OSNA) assay as a single test on whole sentinel lymph nodes (SLN) as a method of intraoperative diagnosis and staging of SLNs in breast cancer.

BACKGROUND

Combining histological and molecular assessment of metastasis on the same SLN may not fully reproduce the actual load of cancer cells present in the SLN and create problems in decisions regarding axillary dissection.

METHODS

Selection criteria for the whole SLN OSNA test required that the primary tumor expressed CK19 in more than 80% of tumor cells. Imprint cytology analysis of SLNs was performed together with the OSNA.

RESULTS

Of the 279 patients enrolled for SLN evaluation, 123 gave consent to the OSNA protocol and 156 to the standard histology. Thirteen patients were excluded from OSNA evaluation because of low CK19 gene expression in the primary tumor; only 2.3% were truly negative. The kappa of concordance between the imprint cytology and OSNA results was 0.52. The rate of macrometastases determined by OSNA was 11% versus 20% determined by histology, whereas the rate of OSNA-micrometastases (18%) was significantly higher than that determined by histology (8%). The rate of SLN-negative cases was similar between the 2 protocols. Macrometastases correlated with the presence of vascular invasion in both protocols. The rate of axillary lymph node metastases was consistent with SLN tumor load.

CONCLUSIONS

Intraoperative OSNA assay performed on the whole SLN gave objective and reproducible results that were useful for directing decisions regarding axillary dissection and for accurately defining the SLN stage.

Frozen section analysis of sentinel lymph nodes in patients with breast cancer does not impair the probability to detect lymph node metastases

Intra-operative frozen section analysis (FS analysis) of sentinel lymph nodes (SLNs) in patients with breast cancer can prevent a second operation for axillary lymph node dissection. In contrast, loss of tissue during FS analysis may impair the probability to detect lymph node metastases. To determine the effect of tissue loss on the probability of detection of metastases, dimensions and tissue loss resulting from intra-operative frozen section analysis were measured for 21 SLNs. In a mathematical model, the influence of tissue loss on the probability to detect metastases was calculated in relation to SLN size for various pathology protocols: an American, a widely used European, the extensive ‘Milan’ and the Dutch protocol. For median-sized SLN 11 × 8 × 5 mm (length × width × height), FS analysis led to a median loss of 680 μm (13.6%) of the height of the SLN. Irrespective of SLN size or used pathology protocol, the probability of detecting 2 mm metastases remained unchanged or even increased (0–12.8%). Moreover, the probability to detect 0.2 mm metastases increased for the majority of tested combinations of SLN size, tissue loss and used protocol. Only when combining maximum tissue loss and smallest SLN size in the Dutch protocol, or when applying the extensive Milan protocol on a median-sized SLN, the probability to detect 0.2 mm metastases decreased by 2.7% and 14.3%, respectively. Contrary to ‘common knowledge’, doing FS analysis of SLNs does not impair the probability to detect lymph node metastases.

Paradigm shift in axilla surgery for breast cancer patients treated with sentinel node biopsy

BACKGROUND

Sentinel node biopsy (SNB) is a standard technique for the diagnosis of regional lymph node metastases in clinically node-negative breast cancer patients. In the case of pathologically negative sentinel lymph nodes (SLN), axillary lymph node dissection (ALND) can be avoided.

METHODS

Recent clinical studies on SNB in breast cancer were reviewed regarding the pathological and molecular diagnosis of SLN, the tools used to predict non-SLN metastases, the prognostic significance of isolated tumor cells (ITC) and micrometastases (MIC), and axilla surgery.

RESULTS

ITC or MIC in SLN was associated with worse survival in patients treated with SNB alone or SNB followed by ALND. However, this effect was limited and adjuvant therapy improved survival. If T1 and one SLN-positive breast cancer patients are treated with whole-breast irradiation and adjuvant therapy, additional ALND may not be necessary.

CONCLUSIONS

SNB without ALND can be adopted for patients with a small number of SLN metastases. Although the lack of apparent regional lymph node recurrence, similar to tumor dormancy, cannot be fully explained, ALND should be performed in cases that are highly suspected to be non-SLN metastases.

Diagnosis of the sentinel lymph node in breast cancer: a reproducible molecular method: a multicentric Spanish study

AIMS

Standardization of the sentinel node (SN) as a diagnostic tool has not yet been achieved, because the protocol for histopathological study is highly variable between centres. We compared the results of a new method with conventional histological tests and evaluated its feasibility for intra-operative evaluation, and propose it as a method to standardize the sentinel node evaluation procedure.

METHODS AND RESULTS

Trial 1 included 181 cases; in parallel, 2-mm-thick sections of the SN were processed alternately for histological analysis and for the one-step nucleic acid amplification (OSNA) procedure. A final concordance of 99.45% was observed in the first trial of our study. For trial 2, the timing of every procedural step was recorded in an electronic database in order to discern the time spent for each step, the total SN evaluation time and to identify areas of improvement. In the second trial, after a learning period and feedback on data recorded, we spent a mean of 31 min for the entire SN evaluation procedure.

CONCLUSION

Our multi-centric trial using the OSNA assay for sentinel node evaluation in breast cancer demonstrates that this is a highly sensitive, specific and reproducible technique that allows for standardization of the SN diagnostic procedure, a necessary, and until now unresolved, issue.

Diagnostic performance of one-step nucleic acid amplification for intraoperative sentinel node metastasis detection in breast cancer patients

The purpose of this prospective multicenter study was to assess one-step nucleic acid amplification (OSNA) for intraoperative sentinel lymph node (SLN) metastasis detection in breast cancer patients, using final histology as the reference standard. OSNA results were also compared to intraoperative histology SLN evaluation and to standard clinicopathological risk markers. For this study, fresh SLNs were cut in four blocks, and alternate blocks were used for OSNA and histology. CK19 mRNA copy number was categorized as strongly positive, positive or negative. Positive histology was defined as presence of macrometastasis or micrometastasis. When discrepancies occurred, the entire SLNs were subjected to histological studies and the node lysates to additional molecular studies. Five hundred three SLN samples from 233 patients were studied. Mean time to evaluate two SLNs was 40 min. Sensitivity per patient was 91.4% (95% CI, 76.9-98.2%), specificity 93.3% (95% CI, 88.6-96.6%), positive likelihood ratio 13.7 and negative likelihood ratio 0.1. Sensitivity was 63.6% for frozen sections and 47.1% for touch imprint cytology. Both methods were 100% specific. Positive histology and positive OSNA were significantly associated with highest clinical stage, N1 status and vascular invasion; and OSNA results correlated with HER2/neu status and benefited patients with negative histology. These findings show that OSNA assay can allow detection of SLN metastasis in breast cancer patients intraoperatively with a good sensitivity, thus minimizing the need for second surgeries for axillary lymph node detection.