COMPUTER-AIDED HER-2/neu EVALUATION IN EXTERNAL QUALITY ASSURANCE (EQA) OF BREAST CANCER SCREENING PROGRAMME

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1 COMPUTER-AIDED HER-2/neu EVALUATION IN EXTERNAL QUALITY ASSURANCE (EQA) OF BREAST CANCER SCREENING PROGRAMME Maria Lunardi MD Anatomic Pathology Fracastoro Hospital San Bonifacio, Verona -Italy

2 HER2-neu HER2 is the most important target for therapy in breast cancer (BC) with estrogen receptor (ER) but After more than 30 years, still uncertainty about the definition of HER2 positivity BC In HER2 testing there is an error rate of about 15%-20% International recommendations are increasing the level of uncertainty amongst pathologists and oncologists Inconsistent thresholds: IHC testing FDA scoring system >10% overexpressing cell vs ASCO/CAP (2007) >30% Not meant to replace the FDA scoring system for eligibility to Trastuzumab

3 2013 Now HER2 testing is recommended for primary, recurrent and metastatic tumors Guidelines emphasized those changes that would mitigate false positive results, particularly relating to issues of specimen fixation and pathologist interpretation But clinical experience has indicated that false-negative HER2 test results must be considered and the Committee decided to revert to the previously used ICH criterion (>10%) for HER2 positive ASCO/CAP recommend image analysis as an effective tool for achieving consistent interpretation of ICH HER2 staining, provided that a pathologist confirms the result Optimal external quality assurance methods to ensure accuracy in HER2 testing and laboratory accreditation

4 External quality assurance (EQA) has been active in the district of Veneto (Italy) since A slide scanner for digital readings has been inuse at the site since During HER2 IHC quality assurance testing within this period, we compared manual evaluation vs computer-aided evaluation The computerized algorithmic analysis Virtuoso software (Ventana, Roche, FDA cleared) has been used for evaluation into two groups of breast cancer (HER2- and HER2+) 25 Centers participating in the EQA met at the plenary session for discussing the virtual slides

5 Materials and methods 25 Centers selected: 48 HER2 negative cases (score 0/1+) (group A) and 23 HER2 positive cases (score 3+) (group B) according to manual evaluation (HERCEPTEST, PATHWAY anti-her2 4B5) Our team stained the immunoslides (PATHWAY anti-her2 4B5-FDA approved) by using a Ventana BenchMark ULTRA staining system

6 iscancoreo High speed bright-field scanning a 15 x 15 mm tissue area can be scanned in less than two minutes at 20X Automatic slide detection for walk-away scanning, random access to the slide rack Automated turret with four objectives, for optical bright-field scanning at 4X, 10X, 20X and 40X magnifications Autoloader for walk-away scanning of up to 160 slides Automatic tissue region identification with option to manually override Volume scanning with the ability to capture multiple z-plane images remote microscopy for telepathology applications

7 Virtuoso is a digital pathology software solution that allows to acquire, manage, view, analyze, share, and report on digital images of pathology specimens. It can be used for review of digitalized images with image analysis algorithms or without (Image Analysis applications vs Digital Read applications) Digital Read applications present images on the computer screen in the same manner as one would see with a manual microscope

8 Image analysis application Two pathologists employed the software to select and outline one or several fields of views (FOVs), which may be viewed at various levels of magnification

9 To obtain HER2 score, the steps involved in the algorithms analysis (at 20x magnification) are: 1. Enhance the image by increasing the contrast 2. Identify the epithelial area 3. Identify the nucleus 4. Identify the cell membrane nucleus cell membrane

10 5. Classify the cells based on extent, intensity and thickness of membrane staining. 6. Compute score: a count of the total number of target cells and the number interpreted as positive or negative for a single FOV or an aggregate score for all selected FOVs.

11 Two pathologists accepted the score provided by the algorithm, confirmed the results and generated the reports.

12 Results: 25 % of disagreement in HER2 positive cases with underscore in Virtuoso software analysis (2+) compared to the manual one (3+) 2 cases HER2 negative are not evaluable due to tissue artifacts

13 Case n. 1 : manual evaluation HER2 IHC positive (score 3+) computer-aided evaluation HER2 IHC borderline (score 2+) FISH test is need

14 Case n. 2 : not evaluable due to crush or edge artifacts specimen handling was inadequate or analytic testing failure

15 Conclusion 1 The Virtuoso Image Analysis application Software assists the pathologist in the semi-quantitative measurement of HER2. The computer-assisted analysis and the manual scoring were highly reproducible in HER2 negative (group A), with no false positive cases. The computer-aided assessment does help in screening negative cases to reduce turnaround time. 25% of disagreement in HER2 positive (group B), with underscore in Virtuoso software analysis (2+) compared to the manual one (3+). In order to guarantee the quality of patient care, in borderline cases the FISH test is needed.

16 Conclusion 2 Image Analysis applications for SISH test in work in progress would increase accuracy and capacity of the test; they seem to be an important and necessary step, before further progress can be made. Agreement analysis performed on the output of the study showed significant improvement in both inter-observer and intra-observer agreement when the computer aided reading mode was used. The accuracy of the test result depends on the quality of the immunohistochemical staining. In recent literature Image Analysis application software showed less false positive rates when used to evaluate IHC equivocal cases. As recommended by CAP/ASCO, the software is an instrument that can aid the pathologist, however the final decision remains on the pathologist.

17 Thanks to Anatomic Pathology team in Fracastoro Hospital Thanks to Veneto breast cancer screening group