ECP 2023 Abstracts

S60 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 analysis revealed 12% discordance for 2 pathologists and 22% for 3, supporting a multi-reviewer approach. Early prototype models achieved 87.5% - 97.1% accuracy at a tile level in detecting diagnostically significant areas against the test set. Conclusion: Definition of ground truth provides a platform to investi- gate methodologies for reviewing and analysing pathology cases, mag- nification levels, architectural changes and feature extraction. Careful definition of the annotation protocol and pathology tool will ultimately enable development of the best aids to the pathologist. Funding: National Pathology Imaging Co-operative, NPIC (Project no. 104687) funded from the £50m investment from the Data to Early Diagnosis and PrecisionMedicine strand of the government’s Industrial Strategy Chal- lenge Fund, managed and delivered by UKResearch and Innovation (UKRI) PS-01-014 Cytological features of breast ductal adenoma F. Di Donato*, M. Cattani, A. Tafa’, M.C. Cucchi, L. Saragoni, M.P. Foschini *School of Anatomic Pathology, Department of Biomedical and Neuro- motor Sciences, University of Bologna, Italy Background & objectives: Ductal Adenoma (DA) of the breast is a benign tumour with a high overdiagnoses risk especially in preoperative procedures. The purpose of this study is to describe specific cytological features of a series of DAs to avoid misdiagnoses of malignancy. Methods: Fourteen cases having a histological diagnosis of DA and a previous cytological examination by Nipple Discharge (ND) or Fine Needle Aspiration Cytology (FNAC) were selected. Clinical and ultra- sound data were collected. Cytological features were evaluated with quantitative and morphological systems. Histological samples of the lesions were reviewed. Cytological and histological aspects were com- pared to identify the spectrum of DA’s cytology. Results: All patients were women, with a mean age of 59 years. Lesions appeared on ultrasound as hypoechoic or anechoic, the range sizewas 1-10mm. The three cases of ND were characterized by numerous red blood cells, conspicuous fluid, poor cellularity and mild/moderate cellular atypia. A diagnosis of suspicion of malignancy was made. The eleven cases studied by ultrasound guided FNAC showed: scarce fluid, high cellularity, mild/moderate atypia, rare stromal fragments, presence of blood, myoepithelial cells, mono/multilayered tissue frag- ments, dispersed bipolar nuclei and singular cells. Cytological reports based on the Yokohama System resulted principally C3 and C4. Histo- logical examination of the lesions confirmed the main diagnosis of DA. Conclusion: DA is a benign tumour, composed of distorted glands in a sclerotic stroma surrounded by a fibrous capsule, that can mimic carcinoma on preoperative procedures. Therefore, knowledge of its cytological features is important to avoid misdiagnoses. High cellular- ity and nuclear atypia may lead to a misdiagnosis of malignancy, but the presence of myoepithelial cells and apocrine changes suggests a benign lesion. Cytology, together with clinical and ultrasound data, allows DA diagnosis avoiding overtreatment. PS-01-015 HER2 assessment in breast cancer – routine diagnostics vs. segment- based annotations in multi-institutional raters J. Steenpass*, M. Öttl, C. Schmidt, M. Ruebner, P.A. Fasching, M.W. Beck- mann, C. Taverna, F. Tava, C. Lang-Schwarz, A. Hartmann, K. Breininger, R. Erber* *Institute of Pathology, University Hospital Erlangen, Comprehen- sive Cancer Center Erlangen-EMN, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany Background & objectives: Human epidermal growth factor receptor 2 (HER2) status is a crucial prognostic and predictive biomarker in invasive breast cancer (IBC). We investigated manual HER2 scoring as performed in routine diagnostics versus exact annotations by five multi-institutional raters with different experience. Methods: HER2 immunohistochemical (IHC) expression was ana- lysed using 80 regions-of-interest (ROIs) out of eight digitized HER2 IHC whole slide images (WSIs) of IBC. After estimating the tumour distribution across the HER2 scores within each ROI, the ROIs were annotated on the open-source image analysis platform EXACT by assigning the correct HER2 score according to the ASCO/CAP guide- lines to pre-segmented tissue structures. Results: The Earth Mover’s Distance (EMD) was used to assess the intra-/interrater agreement on the distributions of HER2 scores: the intra-rater reliability comparing estimated and annotated HER2 scores ranged from 0.059 to 0.155 (mean 0.119) which indicates a certain consistency for each of the five raters. Regarding the inter-rater agree- ment, the median of the EMD was 0.317 for the estimated scores and 0.236 for the exact annotations. In all eight cases, at least three of the five pathologists agreed on the total HER2 score of the WSI. Clini- cally significant difference in HER2 status may occur in up to three estimated and two annotated cases depending on a follow-up in situ hybridization. Conclusion: The study indicates that HER2 scoring is subject to vari- ability; fine-grained annotations resulted in better agreement than esti- mates. Although assessment of HER2 overexpression using IHC is standardized by the ASCO/CAP guidelines, there are concerns about reproducibility and reliability potentially leading to different scores and treatment decisions. Accurate evaluation, especially in HER2-low tumours, has become more important due to the development of new therapeutic options such as antibody-drug conjugates. Further analysis is needed to handle upcoming challenges in HER2 scoring. This project is supported by the Bavarian State Ministry of Health and Care, project grant No. G81d-A1070-2020/257-10 (MGP-2008-0003 and MGP-2010-0004). Katharina Breininger is supported by d.hip campus - Bavarian aim in form of a faculty endowment. Jana Steen- pass is supported by the German Cancer Aid (Deutsche Krebshilfe, Mildred-Scheel Doktorandenprogramm). PS-01-016 Residual lymphovascular invasion after neoadjuvant chemotherapy is associated with poor prognosis in breast carcinoma G. Gasljevic*, N. Pislar, A. Perhavec *Institute of Oncology Ljubljana, Slovenia Background & objectives: The poor prognostic significance of lympho- vascular invasion (LVI) in breast carcinoma (BC)is recognized in several studies. Its prognostic role in post-neoadjuvant chemotherapy (NACT) remains unclear. We wanted to evaluate prognostic importance of residual LVI (rLVI) after NACT and surgery. Methods: 01.01.2008-31.12.2021, 655 BC patients were treated by NACT and surgery. Clinical history and primary tumour characteristics were obtained from database. Residual cancer burden (RCB) system was used for evaluation. Complete pathologic response (pCR) was defined as ypT0/isN0, rLVI as carcinoma cells within endothelial-lined space (H&E). Survival analysis was performed using Kaplan-Meier and covariates were tested with Cox proportional hazards model. Results: Out of 654 tumours (data missing for 1 case), rLVI was pre- sent in 28.9% of patients. Ten out of the 176 patients with pCR had iso- lated rLVI. rLVI was associated with poor disease-free survival (DFS) in univariate analysis (HR 2.36 (95% CI 1.69–3.31), p <0.001) (Fig- ure 1). Tumour size (T1 vs T2 and T3), presence of lymph node (LN) metastases, Her2 positivity and RCB categories II and III were also predictors of poor DFS in univariate analysis. In multivariant analysis, T stage and RCB categories II and III remained significantly associated with poor DFS. Patients’ characteristics as well as the results of uni-and multivariate analyses are summarized in Table 1.