Supervised automated microscopy increases sensitivity and efficiency of detection of sentinel node micrometastases in patients with breast cancer

Ziehl-Neelsen sputum smear microscopy image database: a resource to facilitate automated bacilli detection for tuberculosis diagnosis

Ziehl-Neelsen stained microscopy is a crucial bacteriological test for tuberculosis detection, but its sensitivity is poor. According to the World Health Organization (WHO) recommendation, 300 viewfields should be analyzed to augment sensitivity, but only a few viewfields are examined due to patient load. Therefore, tuberculosis diagnosis through automated capture of the focused image (autofocusing), stitching of viewfields to form mosaics (autostitching), and automatic bacilli segmentation (grading) can significantly improve the sensitivity. However, the lack of unified datasets impedes the development of robust algorithms in these three domains. Therefore, the Ziehl-Neelsen sputum smear microscopy image database (ZNSM iDB) has been developed, and is freely available. This database contains seven categories of diverse datasets acquired from three different bright-field microscopes. Datasets related to autofocusing, autostitching, and manually segmenting bacilli can be used for developing algorithms, whereas the other four datasets are provided to streamline the sensitivity and specificity. All three categories of datasets were validated using different automated algorithms. As images available in this database have distinctive presentations with high noise and artifacts, this referral resource can also be used for the validation of robust detection algorithms. The ZNSM-iDB also assists for the development of methods in automated microscopy.

A systematic review and economic evaluation of intraoperative tests [RD-100i one-step nucleic acid amplification (OSNA) system and Metasin test] for detecting sentinel lymph node metastases in breast cancer

BACKGROUND

In breast cancer patients, sentinel lymph node biopsy is carried out at the same time as the removal of the primary tumour to postoperatively test with histopathology for regional metastases in the sentinel lymph node. Those patients with positive test results are then operated on 2-4 weeks after primary surgery to remove the lymph nodes from the axilla (axillary lymph node dissection, ALND). New molecular tests RD-100i [one-step nucleic acid amplification (OSNA); based on messenger RNA amplification to identify the cytokeratin-19 (CK19) gene marker] (Sysmex, Norderstedt, Germany) and Metasin (using the CK19 and mammaglobin gene markers) (Cellular Pathology, Princess Alexandra Hospital NHS Trust, Harlow, UK) are intended to provide an intraoperative diagnosis, thereby avoiding the need for postoperative histopathology and, in positive cases, a second operation for ALND.

OBJECTIVE

To evaluate the clinical effectiveness and cost-effectiveness of using OSNA and Metasin in the NHS in England for the intraoperative diagnosis of sentinel lymph nodes metastases, compared with postoperative histopathology, the current standard.

DATA SOURCES

Electronic databases including MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, The Cochrane Library and the Health Economic Evaluations Database as well as clinical trial registries, grey literature and conference proceedings were searched up to July 2012.

REVIEW METHODS

A systematic review of the evidence was carried out using standard methods. Single-gate studies were used to estimate the accuracy of OSNA with histopathology as the reference standard. The cost-effectiveness analysis adapted an existing simulation model of the long-term costs and health implications of early breast cancer diagnostic outcomes. The model accounted for the costs of an extended first operation with intraoperative testing, the loss of health-related quality of life (disutility) from waiting for postoperative test results, disutility and costs of a second operation, and long-term costs and disutility from lymphoedema related to ALND, adjuvant therapy, locoregional recurrence and metastatic recurrence.

RESULTS

A total of 724 references were identified in the searches, of which 17 studies assessing test accuracy were included in the review, 15 on OSNA and two on Metasin. Both Metasin studies were unpublished. OSNA sensitivity of 84.5% [95% confidence interval (CI) 74.7% to 91.0%] and specificity of 91.8% (95% CI 87.8% to 94.6%) for patient nodal status were estimated in a meta-analysis of five studies [unadjusted for tissue allocation bias (TAB)]. At these values and a 20% node-positive rate, OSNA resulted in lifetime discounted cost-savings of £498 and a quality-adjusted life-year (QALY) loss of 0.048 relative to histopathology, that is, £4324 saved per QALY lost. The most favourable plausible scenario for OSNA in terms of the node-positive rate (range 10-40%), diagnostic accuracy values (91.3% sensitivity and 94.2% specificity, from three reports that adjusted for TAB), the costs of histopathology, OSNA and second surgery, and long-term costs and utilities resulted in a maximum saving per QALY lost of £10,500; OSNA sensitivity and specificity would need to be ≥ 95% for this figure to be ≥ £20,000.

LIMITATIONS

There is limited evidence on the diagnostic test accuracy of intraoperative tests. The quality of information on costs of resource utilisation during the diagnostic pathway is low and no evidence exists on the disutility of waiting for a second surgery. No comparative studies exist that report clinical outcomes of intraoperative diagnostic tests. These knowledge gaps have more influence on the decision than current uncertainty in the performance of postoperative histopathology in standard practice.

CONCLUSIONS

One-step nucleic acid amplification is not cost-effective for the intraoperative diagnosis of sentinel lymph node metastases. OSNA is less accurate than histopathology and the consequent loss of health benefits in this patient group is not compensated for by health gains elsewhere in the health system that may be obtained with the cost-savings made. The evidence on Metasin is insufficient to evaluate its cost-effectiveness.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012002889.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

An improved axillary staging system using the OSNA assay does not modify the therapeutic management of breast cancer patients

The one-step nucleic acid amplification (OSNA) assay is a molecular procedure that can identify deposits of breast cancer (BC) cells in the sentinel lymph node (SLN). We examined the consistency of the OSNA assay with a classic hematoxylin-eosin (H&E)-based immunohistochemistry (IHC) study and evaluated how OSNA-based axillary staging might impact the therapeutic management of BC patients. SLN biopsy results were considered to be positive in 60 patients (40%) in the OSNA group (N = 148) and in 43 (28%) patients in the IHC cohort (N = 153, p = 0.023). There was no difference in the macrometastasis (22% for OSNA, 15% for H&E, p = 0.139) or micrometastasis (19% for OSNA, 13% for H&E, p = 0.166) rates, but we found statistically significant differences in the number of isolated tumor cells (1% for OSNA, 11% for H&E, p < 0.001). There were no differences in the administration rate of adjuvant systemic therapy between the OSNA (66% in the SLN(+) patients) and the H&E (74% in the SLN(+) patients) groups (p = 0.159). The OSNA assay allows for the detection of SLN metastases more precisely than conventional pathologic methods but does not alter the therapeutic management of SLN(+) BC patients.

Theranostic and molecular classification of breast cancer

CONTEXT

Despite advances in breast cancer management, women continue to relapse and die of breast cancer. Traditionally, evaluation for hormone receptors (estrogen and progesterone), as well as HER2 overexpression, have guided therapy-related decision-making because they are both prognostic and predictive indicators. However, there are limitations with those studies, which can lead to improper treatment. Gene signatures have recently been shown to be of value in identifying molecular portraits of breast carcinoma and are beginning to play role in management and treatment algorithms.

OBJECTIVE

To provide a summary of the prognostic and predictive indicators of breast cancer, such as hormone receptors, HER2, and molecular gene signatures that currently help guide clinical decision making.

DATA SOURCES

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

CONCLUSIONS

Emerging evidence shows promise that, in addition to hormone receptors and HER2 studies, evaluating tumors with gene expression profiling can provide additional prognostic and predictive information, further aiding clinical management and leading to a more personalized approach to treating breast cancer.

Sentinel lymph node micrometastasis in human breast cancer: an update

INTRODUCTION

The advent of sentinel lymph node biopsy (SLNB) and advances in histopathological and molecular analysis techniques have been associated with an increase in micrometastasis (MM) detection rate. However, the clinical significance of sentinel lymph node micrometastasis (SLN MM) continues to be a subject of much debate. In this article we review the literature concerning SLN MM, with particular emphasis on the prognostic significance of SLN MM. The controversies regarding histopathological assessment, clinical relevance and management implications are also discussed.

METHODS

Literature review facilitated by Medline and PubMed databases. Cross referencing of the obtained articles was used to identify other relevant studies.

RESULTS

Published studies have reported divergent and rather conflicting results regarding the clinical significance and implications of axillary lymph node (ALN) MM in general and SLN MM in particular. Some earlier studies demonstrated no associations, however most recent studies have found SLN MM to be an indicator of poorer prognosis and to be associated with non-SLN involvement. The use of adjuvant chemotherapy and/or hormonal manipulation therapy is associated with an improved survival in patients with SLN MM. Complete ALND may be safely omitted provided that adjuvant systemic therapy recommendations are equal to patients with node-positive disease. However, optimal management of SLN MM is yet to conclude. Furthermore, the identification of MM remains largely dependent on the analytical technique employed and the use of immunohistochemistry (IHC) increases the detection rate of SLN MM. Discrepancies in the histopathological interpretation of TNM classification of SLN tumour burden do exist. Published studies were non-randomized and have significant limitations including a small sample size, limited follow-up period, and lack of standardization and reproducibility of pathological examination of the SLN.

CONCLUSION

Patients with SLN MM have a poorer prognosis than those who are SLN negative. Therapeutic recommendations regarding patients with SLN MM should be taken in the context of multidisciplinary team setting and in selected cases of SLN MM, complete ALND may be safely omitted. A better reproducibility of pathological interpretation of the TNM classification is required so that future therapeutic guidelines can be applied without confusion.

Clinical significance of sentinel lymph node isolated tumour cells in breast cancer

The advent of sentinel lymph node biopsy (SLNB) and improvements in histopathological and molecular analysis have increased the rate at which isolated tumour cells (ITC) are identified. However, their biological and clinical significance has been the subject of much debate. In this article we review the literature concerning SLNB with particular reference to ITC. The controversies regarding histopathological assessment, clinical relevance and management implications are explored. The literature review was facilitated by Medline, PubMed, Embase and Cochrane databases. Published studies have reported divergent results regarding the biological significance and clinical implications of ITC in general and SLN ITC in particular. Some studies demonstrate no associations, whilst others have found these to be indicators of poor prognosis, associated with non-SLN involvement, in addition to local recurrence and distant disease. Absolute consensus regarding the optimal analytical technique for SLN has yet to be reached, particularly concerning immunohistochemical (IHC) techniques targeting cytokeratins and contemporary molecular analysis. The clinical relevance of ITC within the SLN should be primarily determined by the magnitude of their impact on patient management and outcome measures. The modest up-staging within current classification systems is justified and reflects the marginally poorer prognosis for women with SLN ITC. Management need not be altered where further axillary treatment with surgical clearance or radiotherapy and systemic adjuvant treatment are already indicated. However, in the absence of level-1 guidance, each case requires discussion with regard to other tumour and patient related factors in the context of the multidisciplinary team. The identification of ITC remains highly dependent on the analytical technique employed and there exists potential for stage migration and impact on management decisions. Evidence supporting the routine analysis of deeper tissue sections by IHC is lacking and molecular technologies should be restricted to research purposes at present.

Creation of a fully digital pathology slide archive by high-volume tissue slide scanning

Digital slide scanners for scanning glass slides are becoming increasingly popular because current scanners are fast enough and produce good enough images for diagnostic purposes, education, and research. Also, the price for storing vast amounts of data has decreased over the last years, and this trend is expected to continue. Where most laboratories use their scanners mainly for education and research with limited financial and technical implications, we decided to face the huge challenges of prospectively setting up a fully digital pathology slide archive, primarily aiming to optimize the preparation and running of clinicopathological conferences. In this article, we describe the setup of our digital archiving solution and discuss the technical challenges we had to overcome. To give insight in the performance of our digital archive, we provide some statistics as well. We also present our thoughts on future developments in the area of digital slide scanning.

Identification and biologic significance of micrometastases in axillary lymph nodes in patients with invasive breast cancer

CONTEXT

The presence or absence of metastases in axillary lymph nodes is one of the most important prognostic factors for patients with breast cancer. During the past decade sentinel lymph node (SLN) biopsy has been increasingly adopted as a minimally invasive staging alternative to complete axillary node dissection.

OBJECTIVE

Sentinel lymph nodes are more likely to contain metastases than non-SLNs. In routine clinical practice SLNs are assessed by diverse methodologies including multiple sectioning, immunohistochemical staining, and molecular diagnostic tests. Despite the lack of standard histopathologic protocols during the years detailed evaluation of SLNs has resulted in an increased detection of small (micro) metastases.

DATA SOURCES

Breast cancer with micrometastases constitutes a heterogenous group of tumors with variable clinical outcome regarding the risk of additional metastases in the remaining axillary lymph nodes and to patients' survival.

CONCLUSION

The clinical significance of micrometastases has been subject to great controversy in patients with breast cancer. In this review we highlight controversies regarding micrometastases especially in relation to SLNs.

The clinical significance of sentinel lymph node micrometastasis in breast cancer

INTRODUCTION

The advent of sentinel lymph node biopsy (SLNB) and improvements in histopathological and molecular analysis have increased the rate at which micrometastases (MM) are identified. However, their significance has been the subject of much debate. In this article we review the literature concerning axillary lymph node (ALN) MM, with particular reference to SLNB. The controversies regarding histopathological assessment, clinical relevance and management implications are discussed.

METHODS

Literature review facilitated by Medline and PubMed databases.

RESULTS

Published studies have reported divergent results regarding the significance and implications of ALN MM in general and sentinel lymph node (SLN) MM in particular. Some studies demonstrate no associations, whilst others have found these to be indicators of poor prognosis, associated with non-SLN involvement, in addition to local and distant failure. Absolute consensus regarding the optimal analytical technique for SLNs has yet to be reached, particularly concerning immunohistochemical (IHC) techniques targeting cytokeratins and the utility of contemporary molecular analysis.

CONCLUSION

SLN MM are likely to represent an incremental detriment to prognosis and increased risk of non-SLN involvement, despite only modest up-staging within current classification systems. In the absence of level-1 guidance concerning the management of women with SLN MM, each case requires discussion with regard to other tumour and patient related factors in the context of the multidisciplinary team. Randomized studies are required to evaluate the prognostic significance and optimal management of each category of tumour burden within the SLN. The identification of MM remains highly dependent on the analytical technique employed and there exists potential for stage migration and impact on management decisions.

What is a positive sentinel lymph node in a breast cancer patient? A practical approach

Sentinel lymph node (SN) biopsy has become increasingly used for the staging of breast carcinoma, resulting in the upstaging of this disease, and this has led to concerns with regard to what should be considered a positive SN. Factors influencing the positive staging of an SN include metastasis size, the method used for metastasis detection, the definition of metastasis and the individual pathologist. Until evidence to the contrary emerges, an SN should be considered positive if metastases (nodal involvement >0.2mm in the largest dimension) are detected in it by histology. A target size should be identified, and SNs, as the most likely sites of nodal metastases, should be searched systematically to find (nearly) all of the targeted metastases. The European guidelines for SN assessment have set two such target sizes: as a minimum, all metastases >2mm should be identified, and optimally all micrometastases should also be sought.

Prognostic relevance of occult tumour cells in lymph nodes in colorectal cancer

AIMS

Presently, in Europe the treatment of node-negative colorectal cancer (CRC) patients consists of surgical resection of the primary tumour without adjuvant systemic therapy. However, up to 30% of these patients will develop disease recurrence. These high-risk patients are possibly identified by occult tumour cell (OTC) assessment in lymph nodes. In this paper, studies on the clinical relevance of OTC in lymph nodes are reviewed.

METHODS

A literature search was conducted in the National Library of Medicine by using the keywords colonic, rectal, colorectal, neoplasm, adenocarcinoma, cancer, lymph node, polymerase chain reaction, mRNA, immunohistochemistry, micrometastases and isolated tumour cells. Additional articles were identified by cross-referencing from papers retrieved in the initial search.

RESULTS

The upstaging percentages through OTC assessment and the prognostic relevance of OTC in lymph nodes vary among studies, which is related to differences in techniques used to detect OTC.

CONCLUSIONS

We conclude that OTC examination techniques should be standardized to illuminate whether OTC in lymph nodes can reliably identify high-risk node-negative patients.

Clinical relevance of occult tumor cells in lymph nodes from gastric cancer patients

The current method for staging in gastric cancer is not sufficient as even after a complete primary tumor resection, patients with node-negative gastric cancer suffer from disease recurrence. In this study, the relation between disease recurrence and the presence of occult tumor cells (OTC) in lymph nodes from gastric cancer patients was evaluated. In a case-control design, lymph nodes from 40 cases (disease recurrence) and 41 controls (no disease recurrence and followed for at least five years) with gastric cancer were examined for the presence of OTC, that comprised micrometastases (MM; >0.2 mm and < or =2.0 mm) and isolated tumor cells (ITC; < or =0.2 mm). The original hematoxylin and eosin-stained sections of all lymph nodes from cases and controls were previously considered as tumor-negative by the local pathologist. Fresh hematoxylin and eosin-stained sections were screened by conventional microscopy. Histologic sections stained by immunohistochemistry with anticytokeratin antibodies CAM5.2 were screened by conventional and automated microscopy. Tumor cells were detected in lymph nodes from 40 of 81 (49%) patients. There was no significant difference in the presence of OTC, MM, or ITC between the case and control groups (P = 0.658, P = 0.691, P = 0.887, respectively). However, significantly more cases presented with 20% or more OTC-positive lymph nodes (P = 0.015). A multivariate logistic regression analysis showed that examination of less than five lymph nodes (odds ratio, 13.8; 95% confidence interval, 1.6-120.6, P = 0.018) was the only significant independent risk factor for disease recurrence, especially for locoregional disease recurrence (odds ratio, 20.4; 95% confidence interval, 2.2-190.8, P = 0.008). A similar analysis for distant disease recurrence showed a percentage of 20% or more OTC-positive lymph nodes to be the only significant independent risk factor (odds ratio, 15.6, 95% confidence interval, 1.6-151.4, P = 0.018). The sensitivity of immunohistochemistry evaluated by microscopy to identify cases with 20% or more OTC-positive lymph nodes increased from 8% for conventional microscopy to 22% for automated microscopy (McNemar's test, P = 0.063). The mere presence of OTC-positive lymph nodes in gastric cancer patients did not predict disease recurrence. However, the number of examined lymph nodes and the percentage of OTC-positive lymph nodes were independent risk factors for locoregional disease recurrence and distant disease recurrence, respectively. Automated microscopy was essential in identifying patients with 20% or more OTC-positive lymph nodes. Therefore, a maximum number of lymph nodes should be removed and meticulously examined for OTC to identify high-risk patients. These patients should be considered for additional treatment.

Improving the reproducibility of diagnosing micrometastases and isolated tumor cells

BACKGROUND

The latest edition of the tumor-lymph node-metastasis (TNM) classification of malignant tumors distinguishes between isolated tumor cells (pN0) and micrometastases (pN1mi). The reproducibility of these categories has not been assessed previously.

METHODS

Digital images from 50 cases with low-volume lymph node involvement from axillary sentinel lymph nodes were circulated twice for evaluation (Evaluation Rounds 1 and 2) among the members of the European Working Group for Breast Screening Pathology, and the members were asked to categorize lesions as micrometastasis, isolated tumor cells, or something else and to classify each case into a pathologic lymph node (pN) category of the pathologic TNM system. Methods for improving the low reproducibility of the categorizations were discussed between the two evaluation rounds. kappa Statistics were used for the assessment of interobserver variability.

RESULTS

The kappa value for the consistency of categorizing low-volume lymph node load into micrometastasis, isolated tumor cells, or neither of those changed from 0.39 to 0.49 between Evaluation Rounds 1 and 2, but it was slightly lower for the pN categories (0.35 and 0.44, respectively). Interpretation of the definitions of isolated tumor cells (especially with respect to their localization within the lymph node), lack of guidance on how to measure them if they were multiple, and lack of any definitions for multiple simultaneous foci of lymph node involvement were listed among the causes of discordant diagnoses.

CONCLUSIONS

The results of the current study indicated that the definitions available have minor contradictions and do not permit a reproducible distinction between micrometastases and isolated tumor cells. Refinement of these definitions, therefore, is required. One refinement that may improve reproducibility is suggested in this report.