Macroscopic photograph and HE-stained overview classification of the breast cancer

Background Establishing macroscopic features of primary breast cancer appears to be helpful in reflecting imaging diagnostic features and may be helpful in predicting histological type such as magnetic resonance imaging classification of breast cancer. Methods Hematoxylin-eosin (HE)-stained pathology slides representative of the tumor’s cut surface were collected from 105 resected breast cancers provided by three facilities. Their macroscopic contours were classified into four types: non-mass, expansive, infiltrative, and mixed. Criteria for these four types were established by examination of the test cohort (60 cases). The interobserver agreement level of the criteria was tested to establish the criteria of the four macroscopic types. To validate the criteria, all 105 cases were independently classified by four pathologists. Agreement level was tested with kappa statistics. Results In the validation of the cohort of the 105 cases, the four observers gave unanimous types to 47/105 cases, three observers gave concordant types to 31/105 cases, and two observers gave concordant types to 41/105 cases. Concordance rates among all four pathologists and between three or more pathologists were 44.8% (47/105) and 74.3% (78/105), respectively. The kappa value among the four pathologists was 0.561, which is moderate and valid for classification with no size limit. Significant differences were not detected between matches for non-mass type, expansive/solid type, infiltrate type, and mixed type. Conclusion The classification method found that the both macroscopic photograph and overview of HE-stained slide classification of breast cancer have a relatively high concordance rate among pathologists.