Immunohistochemical assessment of HER2 low breast cancer: interobserver reproducibility and correlation with digital image analysis.

PURPOSE: The recent findings from the DESTINY-Breast04 trial highlighted the clinical importance of distinguishing between HER2 immunohistochemistry (IHC) scores 0 and 1 + in metastatic breast cancer (BC). However, pathologist interpretation of HER2 IHC scoring is subjective, and standardized methodology is needed. We evaluated the consistency of HER2 IHC scoring among pathologists and the accuracy of digital image analysis (DIA) in interpreting HER2 IHC staining in cases of HER2-low BC. METHODS: Fifty whole-slide biopsies of BC with HER2 IHC staining were evaluated, comprising 25 cases originally reported as IHC score 0 and 25 as 1 +. These slides were digitally scanned. Six pathologists with breast expertise independently reviewed and scored the scanned images, and DIA was applied. Agreement among pathologists and concordance between pathologist scores and DIA results were statistically analyzed using Kendall coefficient of concordance (W) tests. RESULTS: Substantial agreement among at least five of the six pathologists was found for 18 of the score 0 cases (72%) and 15 of the score 1 + cases (60%), indicating excellent interobserver agreement (W = 0.828). DIA scores were highly concordant with pathologist scores in 96% of cases (47/49), indicating excellent concordance (W = 0.959). CONCLUSION: Although breast subspecialty pathologists were relatively consistent in evaluating BC with HER2 IHC scores of 0 and 1 +, DIA may be a reliable supplementary tool to enhance the standardization and quantification of HER2 IHC assessment, especially in challenging cases where results may be ambiguous (i.e., scores 0-1 +). These findings hold promise for improving the accuracy and consistency of HER2 testing.

Core Needle Biopsy Guidance Based on Tissue Morphology Assessment with AI-OCT Imaging.

This paper presents a combined optical imaging/artificial intelligence (OI/AI) technique for the real-time analysis of tissue morphology at the tip of the biopsy needle, prior to collecting a biopsy specimen. This is an important clinical problem as up to 40% of collected biopsy cores provide low diagnostic value due to high adipose or necrotic content. Micron-scale-resolution optical coherence tomography (OCT) images can be collected with a minimally invasive needle probe and automatically analyzed using a computer neural network (CNN)-based AI software. The results can be conveyed to the clinician in real time and used to select the biopsy location more adequately. This technology was evaluated on a rabbit model of cancer. OCT images were collected with a hand-held custom-made OCT probe. Annotated OCT images were used as ground truth for AI algorithm training. The overall performance of the AI model was very close to that of the humans performing the same classification tasks. Specifically, tissue segmentation was excellent (~99% accuracy) and provided segmentation that closely mimicked the ground truth provided by the human annotations, while over 84% correlation accuracy was obtained for tumor and non-tumor classification.

Assessment of breast cancer surgical margins with multimodal optical microscopy: A feasibility clinical study.

Providing surgical margin information during breast cancer surgery is crucial for the success of the procedure. The margin is defined as the distance from the tumor to the cut surface of the resection specimen. The consensus among surgeons and radiation oncologists is that there should be no tumor left within 1 to maximum 2 mm from the surface of the surgical specimen. If a positive margin remains, there is substantial risk for tumor recurrence, which may also result in potentially reduced cosmesis and eventual need for mastectomy. In this paper we report a novel multimodal optical imaging instrument based on combined high-resolution confocal microscopy-optical coherence tomography imaging for assessing the presence of potential positive margins on surgical specimens. Since rapid specimen analysis is critical during surgery, this instrument also includes a fluorescence imaging channel to enable rapid identification of the areas of the specimen that have potential positive margins. This is possible by specimen incubation with a cancer specific agent prior to imaging. In this study we used a quenched contrast agent, which is activated by cancer specific enzymes, such as urokinase plasminogen activators (uPA). Using this agent or a similar one, one may limit the use of high-resolution optical imaging to only fluorescence-highlighted areas for visualizing tissue morphology at the sub-cellular scale and confirming or ruling out cancer presence. Preliminary evaluation of this technology was performed on 20 surgical specimens and testing of the optical imaging findings was performed against histopathology. The combination of the three imaging modes allowed for high correlation between optical image analysis and histological ground-truth. The initial results are encouraging, showing instrument capability to assess margins on clinical specimens with a positive predictive value of 1.0 and a negative predictive value of 0.83.

Development of Functional Requirements for Ex Vivo Pathology Applications of In Vivo Microscopy Systems: A Proposal From the In Vivo Microscopy Committee of the College of American Pathologists.

CONTEXT.­: In vivo microscopy (IVM) allows direct, real-time visualization of tissue histology in living patients without the need for tissue removal, processing, or staining. The IVM technologies in clinical use include confocal microscopy and optical coherence tomography. These technologies also show promise for use with pathology specimens (ex vivo microscopy [EVM]). However, few systems designed for EVM are commercially available, at least in part because of the lack of defined minimal functional requirements (FRs). OBJECTIVE.­: To develop minimal FRs for likely high-volume pathology applications of EVM. DESIGN.­: The IVM Committee of the College of American Pathologists identified potential EVM pathology applications based on the published literature. A subcommittee of IVM and EVM early adopters and experts then defined FRs for the most likely EVM applications. RESULTS.­: Potential EVM applications include assessment of margins, adequacy of needle biopsies and aspirates for diagnosis, and transplant tissues; selection of tissue for molecular studies or biorepository; and guidance in block selection from gross specimens. The first 3 applications were selected for development of FRs. The FRs were identified based on existing laboratory practices and guidelines and input from experts in the field and included device footprint and portability, specimen preparation, imaging time, field of view or resolution, morphologic diagnostic capability, yield, accuracy, ease of use, safety, and cost. CONCLUSIONS.­: Consensus was achieved on FRs that would accommodate the selected EVM applications. Publication and dissemination of those FRs will provide guidance to engineers, researchers, and vendors on how to optimally adapt IVM technologies for EVM for widespread adoption by pathologists.

Biopsy Feasibility Trial for Breast Cancer Pathologic Complete Response Detection after Neoadjuvant Chemotherapy: Imaging Assessment and Correlation Endpoints.

PURPOSE: This study was designed to present the secondary imaging endpoints of the trial for evaluating mammogram (MMG), ultrasound (US) and image guided biopsy (IGBx) assessment of pathologic complete response (pCR) in breast cancer (BC) patients undergoing neoadjuvant chemotherapy (NAC). METHODS: Patients with T1-3, N0-3, M0 triple-negative or HER2-positive BC who received NAC were enrolled in an Institutional Review Board-approved prospective, clinical trial. Patients underwent US and MMG at baseline and after NAC. Images were evaluated for residual abnormality and to determine modality for IGBx [US-guided (USG) or stereotactic guided (SG)]. Fine-needle aspiration and 9-G, vacuum-assisted core biopsy (VACBx) of tumor bed was performed after NAC and was compared with histopathology at surgery. RESULTS: Forty patients were enrolled. Median age was 50.5 (range 26-76) years; median baseline tumor size was 2.4 cm (range 0.8-6.3) and 1 cm (range 0-5.5) after NAC. Nineteen patients had pCR: 6 (32%) had residual Ca2+ presurgery, 5 (26%) residual mass, 1 (5%) mass with calcifications, and 7 (37%) no residual imaging abnormality. Sensitivity, specificity, and accuracy of US, MMG, and IGBx for pCR were 47/95/73%, 53/90/73%, and 100/95/98%, respectively. Twenty-five (63%) patients had SGBx and 15 (37%) had US-guided biopsy (USGBx). Median number of cores was higher with SGBx (12, range 6-14) than with USGBx (8, range 4-12), p < 0.002. Positive predictive value for pCR was significantly higher for SG VACBx than for USG VACBx (100 vs. 60%, p < 0.05). CONCLUSIONS: SG VACBx is the preferred IGBx modality for identifying patients with pCR for trials testing the safety of eliminating surgery.

Micro-anatomical quantitative optical imaging: toward automated assessment of breast tissues.

INTRODUCTION: Pathologists currently diagnose breast lesions through histologic assessment, which requires fixation and tissue preparation. The diagnostic criteria used to classify breast lesions are qualitative and subjective, and inter-observer discordance has been shown to be a significant challenge in the diagnosis of selected breast lesions, particularly for borderline proliferative lesions. Thus, there is an opportunity to develop tools to rapidly visualize and quantitatively interpret breast tissue morphology for a variety of clinical applications. METHODS: Toward this end, we acquired images of freshly excised breast tissue specimens from a total of 34 patients using confocal fluorescence microscopy and proflavine as a topical stain. We developed computerized algorithms to segment and quantify nuclear and ductal parameters that characterize breast architectural features. A total of 33 parameters were evaluated and used as input to develop a decision tree model to classify benign and malignant breast tissue. Benign features were classified in tissue specimens acquired from 30 patients and malignant features were classified in specimens from 22 patients. RESULTS: The decision tree model that achieved the highest accuracy for distinguishing between benign and malignant breast features used the following parameters: standard deviation of inter-nuclear distance and number of duct lumens. The model achieved 81 % sensitivity and 93 % specificity, corresponding to an area under the curve of 0.93 and an overall accuracy of 90 %. The model classified IDC and DCIS with 92 % and 96 % accuracy, respectively. The cross-validated model achieved 75 % sensitivity and 93 % specificity and an overall accuracy of 88 %. CONCLUSIONS: These results suggest that proflavine staining and confocal fluorescence microscopy combined with image analysis strategies to segment morphological features could potentially be used to quantitatively diagnose freshly obtained breast tissue at the point of care without the need for tissue preparation.

Is intraoperative touch imprint cytology of sentinel lymph nodes in patients with breast cancer cost effective?

BACKGROUND: Sentinel lymph nodes (SLNs) are generally evaluated postoperatively, requiring 5-7 days for assessment. SLNs can also be evaluated intraoperatively by using touch imprint cytology (TIC), thus providing the surgeon immediate feedback and allowing for concurrent completion node dissection (CND) for positive SLNs. The authors hypothesized that TIC, when compared with standard postoperative SLN assessment alone, would permit a cost-effective evaluation of SLNs in patients with clinically node-negative breast cancer. METHODS: A decision-analysis model was created to compare TIC with standard postoperative SLN assessment alone. Sensitivity and specificity of TIC were determined prospectively from 342 patients who underwent SLN biopsy assessed by both techniques. Short-term health states associated with surgical staging were defined, and utilities were estimated using EuroQol-5D. Base-case analysis was performed to estimate quality-adjusted life years and the incremental cost-effectiveness ratio. Sensitivity analyses were performed to examine stability of model parameters. RESULTS: For each tumor stage, TIC was cost effective, and for patients with larger tumors (T3 and T4), TIC was the dominant strategy. The analysis was robust to changes in sensitivity and specificity of TIC, prevalence of metastasis, probability of complications, and cost. However, when utility associated with standard SLN assessment was 0.9 or greater, this became the preferred strategy. CONCLUSIONS: TIC is cost effective for assessing SLN metastasis intraoperatively. For patients with larger tumors, it is not only more effective, but also less costly than standard SLN assessment alone. TIC may be particularly useful for patients who experience significant anxiety while awaiting results of standard SLN assessment.