Digital validation of breast biomarkers (ER, PR, AR, and HER2) in cytology specimens using three different scanners

Abstract

Progression in digital pathology has yielded new opportunities for a remote work environment. We evaluated the utility of digital review of breast cancer immunohistochemical prognostic markers (IHC) using whole slide images (WSI) from formalin fixed paraffin embedded (FFPE) cytology cell block specimens (CB) using three different scanners. CB from 20 patients with breast cancer diagnosis and available IHC were included. Glass slides including 20 Hematoxylin and eosin ( H&E), 20 Estrogen Receptor (ER), 20 Progesterone Receptor (PR), 16 Androgen Receptor (AR), and 20 Human Epidermal Growth Factor Receptor 2 (HER2) were scanned on 3 different scanners. Four breast pathologists reviewed the WSI and recorded their semi-quantitative scoring for each marker. Kappa concordance was defined as complete agreement between glass/digital pairs. Discordances between microscopic and digital reads were classified as a major when a clinically relevant change was seen. Minor discordances were defined as differences in scoring percentages/staining pattern that would not have resulted in a clinical implication. Scanner precision was tabulated according to the success rate of each scan on all three scanners. In total, we had 228 paired glass/digital IHC reads on all 3 scanners. There was strong concordance kappa 0.85 for all pathologists when comparing paired microscopic/digital reads. Strong concordance (kappa 0.86) was also seen when comparing reads between scanners. Twenty-three percent of the WSI required rescanning due to barcode detection failures, 14% due to tissue detection failures, and 2% due to focus issues. Scanner 1 had the best average precision of 92%. HER2 IHC had the lowest intra-scanner precision (64%) among all stains. This study is the first to address the utility of WSI in breast cancer IHC in CB and to validate its reporting using 3 different scanners. Digital images are reliable for breast IHC assessment in CB and offer similar reproducibility to microscope reads.

Validation of cytopathology specimens for digital pathology

“…For LBC cervical samples, specifically, agreement was 99.2%, similar to the findings of a previously published study that showed excellent agreement between analogical and digital diagnoses using just one focal plane for scanning at 20× 11 . Older studies comparing glass slides and virtual slides for cervical cytology have also shown good concordance, as well as a recent study using cell blocks 13,18–20 . However, not all LBC preparations are very thin or consist of a single layer of cells, and some groups of cells may be out of focus.…”

“…11 Older studies comparing glass slides and virtual slides for cervical cytology have also shown good concordance, as well as a recent study using cell blocks. 13,[18][19][20] However, not all LBC preparations are very thin or consist of a single layer of cells, and some groups of cells may be out of focus. In fact, two cases of major discrepancies in our study were cervical LBC, with analogical diagnoses of LSIL and digital interpretations of negative for intraepithelial lesion or malignancy (NILM).…”

“…Digital cytopathology, however, is slightly behind in terms of wider implementation, mainly due to technical issues such as the three‐dimensionality of the specimens, paucicellular samples and the wide variability of preparations 6–8 . It has been widely used for telecytology and rapid on‐site evaluation, 9,10 but few papers have compared actual diagnoses obtained using whole slide images (WSIs) with those obtained using glass slides 11–13 , and even fewer have followed the CAP guidelines for the validation of WSI in a clinical setting 14 …”

“…5 Digital cytopathology, however, is slightly behind in terms of wider implementation, mainly due to technical issues such as the three-dimensionality of the specimens, paucicellular samples and the wide variability of preparations. [6][7][8] It has been widely used for telecytology and rapid on-site evaluation, 9,10 but few papers have compared actual diagnoses obtained using whole slide images (WSIs) with those obtained using glass slides [11][12][13] , and even fewer have followed the CAP guidelines for the validation of WSI in a clinical setting. 14 In the current study, we aimed to validate different types of cytological preparations for routine clinical use in digital pathology, following the 2021 CAP guidelines, and also to highlight specific characteristics and difficulties involved in the use of such preparations in clinical everyday digital sign-out.…”

Integrating and validating automated digital imaging analysis of estrogen receptor immunohistochemistry in a fully digital workflow for clinical use

“…Previous study has demonstrated non-inferiority for interpreting breast cancer biomarkers on cell block WSIs. 24 Our preliminary data suggest tumor detection algorithm in current ER DIA can reliably detect tumor cells in cell block sections. In addition, breast carcinomas in cytology specimens are mostly metastasis and in situ carcinoma component does not exist to interfere the interpretation of ER IHCs.…”