title: Digital image analysis outperforms manual biomarker assessment in breast cancer.
abstract: In the spectrum of breast cancers, categorization according to the four gene expression-based subtypes 'Luminal A,' 'Luminal B,' 'HER2-enriched,' and 'Basal-like' is the method of choice for prognostic and predictive value. As gene expression assays are not yet universally available, routine immunohistochemical stains act as surrogate markers for these subtypes. Thus, congruence of surrogate markers and gene expression tests is of utmost importance. In this study, 3 cohorts of primary breast cancer specimens (total n=436) with up to 28 years of survival data were scored for Ki67, ER, PR, and HER2 status manually and by digital image analysis (DIA). The results were then compared for sensitivity and specificity for the Luminal B subtype, concordance to PAM50 assays in subtype classification and prognostic power. The DIA system used was the Visiopharm Integrator System. DIA outperformed manual scoring in terms of sensitivity and specificity for the Luminal B subtype, widely considered the most challenging distinction in surrogate subclassification, and produced slightly better concordance and Cohen's κ agreement with PAM50 gene expression assays. Manual biomarker scores and DIA essentially matched each other for Cox regression hazard ratios for all-cause mortality. When the Nottingham combined histologic grade (Elston-Ellis) was used as a prognostic surrogate, stronger Spearman's rank-order correlations were produced by DIA. Prognostic value of Ki67 scores in terms of likelihood ratio χ(2) (LR χ(2)) was higher for DIA that also added significantly more prognostic information to the manual scores (LR-Δχ(2)). In conclusion, the system for DIA evaluated here was in most aspects a superior alternative to manual biomarker scoring. It also has the potential to reduce time consumption for pathologists, as many of the steps in the workflow are either automatic or feasible to manage without pathological expertise.
authors.affiliation: Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden.|St Erik Eye Hospital, Stockholm, Sweden.
authors.forename: Gustav
authors.initials: G
authors.lastname: Stålhammar
authors.affiliation: Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden.|Södersjukhuset, Stockholm, Sweden.
authors.forename: Nelson
authors.initials: N
authors.lastname: Fuentes Martinez
authors.affiliation: Visiopharm A/S, Hoersholm, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Lippert
authors.affiliation: Cancer Center Karolinska, Stockholm, Sweden.
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Tobin
authors.affiliation: Visiopharm A/S, Hoersholm, Denmark.|Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark.
authors.forename: Ida
authors.initials: I
authors.lastname: Mølholm
authors.affiliation: Department of Clinical Pathology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Lorand
authors.initials: L
authors.lastname: Kis
authors.affiliation: Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Gustaf
authors.initials: G
authors.lastname: Rosin
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Mattias
authors.initials: M
authors.lastname: Rantalainen
authors.affiliation: Visiopharm A/S, Hoersholm, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Pedersen
authors.affiliation: Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden.|Cancer Center Karolinska, Stockholm, Sweden.|Department of Oncology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Bergh
authors.affiliation: Visiopharm A/S, Hoersholm, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Grunkin
authors.affiliation: Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden.|Cancer Center Karolinska, Stockholm, Sweden.|Department of Clinical Pathology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Hartman
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000145:classification*; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007150:Immunohistochemistry; D008875:Middle Aged; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor