Diagnostic concordance and discordance in digital pathology : a systematic review and meta-analysis

Background – Digital pathology (DP) has the potential to fundamentally change the way that histopathology is practiced, by streamlining the workflow, increasing efficiency, improving diagnostic accuracy and facilitating the platform for implementation of artificial intelligence-based computerassisted diagnostics. Although the barriers to wider adoption of digital pathology have been multifactorial, limited evidence of reliability has been a significant contributor. A meta-analysis to demonstrate the combined accuracy and reliability of DP is still lacking in the literature. Objectives – We aimed to review the published literature on the diagnostic use of DP and to synthesise a statistically pooled evidence on safety and reliability of DP for routine diagnosis (primary and secondary) in the context of validation process. Methods – A comprehensive literature search was conducted through PubMed, Medline, EMBASE, Cochrane Library and Google Scholar for studies published between 2013 and August 2019. The search protocol identified all studies comparing DP with light microscopy (LM) reporting for diagnostic purposes, predominantly including H&E stained slides. Random-effects meta-analysis was used to pool evidence from the studies. Results – Twenty five studies were deemed eligible to be included in the review which examined a total of 10,410 histology samples (average sample size 176). For overall concordance (clinical concordance) the agreement percentage was 98.3% (95% Confidence interval: 97.4 – 98.9) across 24 studies. A total of 546 major discordances were reported across 25 studies. Over half (57%) of these were related to assessment of nuclear atypia, grading of dysplasia and malignancy. These were followed by challenging diagnoses (26%) and identification of small objects (16%). Conclusion - The results of this meta-analysis indicate equivalent performance of DP in comparison to LM for routine diagnosis. Furthermore, the results provide valuable information concerning the areas of diagnostic discrepancy which may warrant particular attention in the transition to DP

Myxovirus resistance 1 (MX1) is an independent predictor of poor outcome in invasive breast cancer

Background: Breast cancer (BC) is a disease with variable morphology, clinical behaviour and response to therapy. Identifying factors associated with the progression of early stage BC can help understand the risk of metastasis and guide treatment decisions. Myxovirus resistance 1 (MX1), which is involved in the cellular antiviral mechanism, plays a role in some solid tumours; however, its role in invasive BC remains unknown. In this study, we aimed to explore the clinicopathological and prognostic significance of MX1 in BC.Methods: MX1 was assessed at the protein level using tissue microarrays from a large well-annotated BC cohort (n=845). The expression of MX1 mRNA was assessed at the transcriptomic level using the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC; n=1980) and validated using three publicly available cohorts on Breast Cancer Gene-Expression Miner (bc-GenExMiner version 4.4). The associations between MX1 expression and clinicopathological factors, and outcome were evaluated.Results: High MX1 protein expression was associated with features of aggressiveness, including large tumour size, high tumour grade, high Nottingham prognostic index scores, hormone receptor negativity and high Ki67 expression. High MX1 expression showed an association with poor patient outcome and it was an independent predictor of short BC- specific survival (p=0.028; HR=1.5; 95%CI=1.0–2.2). Consistent with the protein results, high MX1 mRNA levels showed an association with features of aggressive behaviour and with shorter survival.Conclusion: This study identified MX1 as an independent predictor of poor outcome in patients with BC. Further functional studies are needed to investigate the biological role of MX1 in BC and its potential value as a therapeutic target

The clinical and biological significance of HER2 over-expression in breast ductal carcinoma in situ: a large study from a single institution

© 2019, Cancer Research UK. Background: Previous studies have reported up to 50% of ductal carcinoma in situ (DCIS), is HER2 positive, but the frequency of HER2-positive invasive breast cancer (IBC) is lower. The aim of this study is to characterise HER2 status in DCIS and assess its prognostic value. Methods: HER2 status was evaluated in a large series of DCIS (n = 868), including pure DCIS and DCIS associated with IBC, prepared as tissue microarrays (TMAs). HER2 status was assessed using immunohistochemistry (IHC) and chromogenic in situ hybridisation (CISH). Results: In pure DCIS, HER2 protein was over-expressed in 9% of DCIS (3+), whereas 15% were HER2 equivocal (2+). Using CISH, the final HER2 status was positive in 20%. In mixed DCIS, HER2 amplification of the DCIS component was detected in 15% with amplification in the invasive component of only 12%. HER2-positive DCIS was associated with features of aggressiveness (p < 0.0001) and more frequent local recurrence (p = 0.03). On multivariate analysis, combined HER2+/Ki67+ profile was an independent predictor of local recurrence (p = 0.006). Conclusions: The frequency of HER2 positivity in DCIS is comparable to IBC- and HER2-positive DCIS is associated with features of poor prognosis. The majority of HER2 over-expression in DCIS is driven by gene amplification

Surgical management of ductal carcinoma in situ of the breast: A large retrospective study from a single institution

Background: Management of breast ductal carcinoma in situ (DCIS) has various approaches with distinct institutional specific practice. Here, we review DCIS management in a single institution with emphasise on re-operation rates and outcome. Methods: DCIS cases diagnosed at the Nottingham Breast Institute between 1987 and 2017 were identified (n=1,249). Clinicopathological data was collected. Cases were histologically reviewed, and different factors associated with primary operation selection, re-excision, presence of residual tumour in the re-excision specimens, use of radiotherapy and ipsilateral recurrences were analysed. Results: 34% of DCIS patients were initially treated by mastectomy and were more frequently symptomatic, of high nuclear tumour grade, size >40mm, and associated with comedo necrosis and Paget’s disease of the nipple. Further surgery was due to involved or narrow surgical margins. Residual tumour tissue was detected in 53% of the re-excision specimens. Re-excision rates of patients treated with breast conserving surgery (BCS) were reduced from approximately 70% to 23% and the final mastectomy rates decreased from 60% to 20%. Changes in surgical practice with acceptance of smaller excision margins and more frequent use of local radiotherapy have led to a significant decrease not only in the re-excision rate but also in the final mastectomy rate together with non-significant reduction in 5- and 10-year local recurrence rates. Conclusion: Although BCS is increasingly the preferred primary surgical option for DCIS management, a proportion of low-risk DCIS patients continue to undergo re-excision surgery or completion mastectomy. Despite acceptance of smaller margins, recurrence rate is decreasing

Legumain is an independent predictor for invasive recurrence in breast ductal carcinoma in situ

© 2018, United States & Canadian Academy of Pathology. Legumain is a proteolytic enzyme that plays a role in the regulation of cell proliferation in invasive breast cancer. Studies evaluating its role in ductal carcinoma in situ (DCIS) are lacking. Here, we aimed to characterize legumain protein expression in DCIS and evaluate its prognostic significance. Legumain was assessed immunohistochemically in a tissue microarray of a well-characterized cohort of DCIS (n = 776 pure DCIS and n = 239 DCIS associated with invasive breast cancer (DCIS-mixed)). Legumain immunoreactivity was scored in tumor cells and surrounding stroma and related to clinicopathological parameters and patient outcome. High legumain expression was observed in 23% of pure DCIS and was associated with features of high-risk DCIS including higher nuclear grade, comedo necrosis, hormone receptor negativity, HER2 positivity, and higher proliferation index. Legumain expression was higher in DCIS associated with invasive breast cancer than in pure DCIS (p < 0.0001). In the DCIS-mixed cohort, the invasive component showed higher legumain expression than the DCIS component (p < 0.0001). Legumain was an independent predictor of shorter local recurrencefree interval for all recurrences (p = 0.0003) and for invasive recurrences (p = 0.002). When incorporated with other risk factors, legumain provided better patient risk stratification. High legumain expression is associated with poor prognosis in DCIS and could be a potential marker to predict DCIS progression to invasive disease

The prognostic significance of lysosomal protective protein (Cathepsin A) in breast ductal carcinoma in situ

Background: Cathepsin A (CTSA) is a key regulatory enzyme for galactoside metabolism. Additionally, it has a distinct proteolytic activity and plays a role in tumour progression. CTSA is differentially expressed at the mRNA level between breast ductal carcinoma in situ (DCIS) and invasive breast carcinoma (IBC). In this study, we aimed to characterise CTSA protein expression in DCIS and evaluate its prognostic significance. Methods: A large cohort of DCIS (n=776 for pure DCIS and n=239 for DCIS associated with IBC (DCIS/IBC)) prepared as tissue microarray was immunohistochemically stained for CTSA. Results: High CTSA expression was observed in 48% of pure DCIS. High expression was associated with features of poor DCIS prognosis including younger age at diagnosis (less than 50 years), higher nuclear grade, hormone receptor negativity, HER2 positivity, high proliferative index and high hypoxia inducible factor 1 alpha expression. High CTSA expression was associated with shorter recurrence free interval (RFI) (p=0.0001). In multivariate survival analysis for patients treated with breast conserving surgery, CTSA was an independent predictor of shorter RFI (p=0.015). DCIS associated with IBC showed higher CTSA expression than pure DCIS (p=0.04). In the DCIS/IBC cohort, CTSA expression was higher in the invasive component than DCIS component (p less than 0.0001). Conclusion: CTSA is not only associated with aggressive behaviour and poor outcome in DCIS but also a potential marker to predict co-existing invasion in DCIS

Morphological and molecular changes of oestrogen receptor‐positive breast cancer following bridging endocrine therapy:a United Kingdom multicentre study

Aims: Standard neoadjuvant endocrine therapy (NAET) is used for 6–9 months to downstage hormone‐receptor‐positive breast cancer. Bridging ET was introduced during the COVID‐19 pandemic to delay surgical intervention. There are no data in the literature on the effect of short course therapy on tumour response. We aimed to analyse the effect of bridging ET and validate the previously proposed neoadjuvant ET pathological reporting criteria. Methods and Results: This was a multicentre cohort of 256 patients who received bridging ET between March and October 2020. Assessment of paired pre‐ and post‐NAET hormone receptors and HER2 and posttherapy Ki67 expression was done. The median duration of NAET was 45 days. In all, 86% of cases achieved partial pathological response and 9% showed minimal residual disease. Histological response to ET was observed from as early as day 6 posttherapy. Central scarring was noted in 32.8% of cases and lymphocytic infiltrate was seen in 43.4% of cases. Significant changes associated with the duration of ET were observed in tumour grade (21%), with downgrading identified in 12% of tumours (P &lt; 0.001), progesterone receptor (PR) expression with switch to PR‐negative status in 26% of cases (P &lt; 0.001), and HER2 status with a switch from HER2‐low to HER2‐negative status in 32% of cases (P &lt; 0.001). The median patient survival was 475 days, with an overall survival rate of 99.6%. Conclusions: Changes characteristic of tumour regression and significant changes in PR and HER2 occurred following a short course of NAET. The findings support biomarker testing on pretreatment core biopsies and retesting following therapy

Aurora Kinase A Is an Independent Predictor of Invasive Recurrence in Breast Ductal Carcinoma in situ

Aurora Kinase A (AURKA/STK15) has a role in centrosome duplication and is a regulator of mitotic cell proliferation. It is over-expressed in breast cancer and other cancers, however; its role in ductal carcinoma in situ (DCIS) remains to be defined. This study aims to characterize AURKA protein expression in DCIS and evaluate its prognostic significance. Methods: AURKA was assessed immunohistochemically in a large well-characterized cohort of DCIS (n = 776 pure DCIS and 239 DCIS associated with invasive breast cancer [DCIS-mixed]) with long-term follow-up data (median = 105 months) and basic molecular characterization. Results: High AURKA expression was observed in 15% of DCIS cases and was associated with features of aggressiveness including larger tumour size, high nuclear grade, hormone receptor negativity, HER2 positivity, and high Ki67 proliferation index. AURKA expression was higher in DCIS associated with invasive breast cancer than in pure DCIS (p < 0.0001). In the DCIS-mixed cohort, the invasive component showed higher AURKA expression than the DCIS component (p < 0.0001). Outcome analysis revealed that AURKA was a predictor of invasive recurrence (p = 0.002). Conclusion: High AURKA expression is associated with poor prognosis in DCIS and might be a potential marker to predict DCIS progression to invasive disease

Improving mitotic cell counting accuracy and efficiency using phosphohistone‐H3 ( PHH3 ) antibody counterstained with haematoxylin and eosin as part of breast cancer grading

Background: Mitotic count in breast cancer is an important prognostic marker. Unfortunately, substantial inter‐ and intraobserver variation exists when pathologists manually count mitotic figures. To alleviate this problem, we developed a new technique incorporating both haematoxylin and eosin (H&E) and phosphorylated histone H3 (PHH3), a marker highly specific to mitotic figures, and compared it to visual scoring of mitotic figures using H&E only. Methods: Two full‐face sections from 97 cases were cut, one stained with H&E only, and the other was stained with PHH3 and counterstained with H&E (PHH3–H&E). Counting mitoses using PHH3–H&E was compared to traditional mitoses scoring using H&E in terms of reproducibility, scoring time, and the ability to detect mitosis hotspots. We assessed the agreement between manual and image analysis‐assisted scoring of mitotic figures using H&E and PHH3–H&E‐stained cells. The diagnostic performance of PHH3 in detecting mitotic figures in terms of sensitivity and specificity was measured. Finally, PHH3 replaced the mitosis score in a multivariate analysis to assess its significance. Results: Pathologists detected significantly higher mitotic figures using the PHH3–H&E (median ± SD, 20 ± 33) compared with H&E alone (median ± SD, 16 ± 25), P < 0.001. The concordance between pathologists in identifying mitotic figures was highest when using the dual PHH3–H&E technique; in addition, it highlighted mitotic figures at low power, allowing better agreement on choosing the hotspot area (k = 0.842) in comparison with standard H&E (k = 0.625). A better agreement between image analysis‐assisted software and the human eye was observed for PHH3‐stained mitotic figures. When the mitosis score was replaced with PHH3 in a Cox regression model with other grade components, PHH3 was an independent predictor of survival (hazard ratio [HR] 5.66, 95% confidence interval [CI] 1.92–16.69; P = 0.002), and even showed a more significant association with breast cancer‐specific survival (BCSS) than mitosis (HR 3.63, 95% CI 1.49–8.86; P = 0.005) and Ki67 (P = 0.27). Conclusion: Using PHH3–H&E‐stained slides can reliably be used in routine scoring of mitotic figures and integrating both techniques will compensate for each other's limitations and improve diagnostic accuracy, quality, and precision

The prognostic significance of immune microenvironment in breast ductal carcinoma in situ

BackgroundThe role of different subtypes of tumour infiltrating lymphocytes (TILs) in breast ductal carcinoma in situ (DCIS) is still poorly defined. This study aimed to assess the prognostic significance of B and T lymphocytes and immune checkpoint proteins expression in DCIS.MethodsA well characterised DCIS cohort (n = 700) with long-term follow-up comprising pure DCIS (n = 508) and DCIS mixed with invasive carcinoma (IBC; n = 192) were stained immunohistochemically for CD20, CD3, CD4, CD8, FOXP3, PD1 and PDL1. Copy number variation and TP53 mutation status were assessed in a subset of cases (n = 58).ResultsCD3+ lymphocytes were the predominant cell subtype in the pure DCIS cohort, while FOXP3 showed the lowest levels. PDL1 expression was mainly seen in the stromal TILs. Higher abundance of TILs subtypes was associated with higher tumour grade, hormone receptor negativity and HER2 positivity. Mutant TP53 variants were associated with higher levels of stromal CD3+, CD4+ and FOXP3+ cells. DCIS coexisting with invasive carcinoma harboured denser stromal infiltrates of all immune cells and checkpoint proteins apart from CD4+ cells. Stromal PD1 was the most differentially expressed protein between DCIS and invasive carcinoma (Z = 5.8, p