Prospective and Retrospective Analysis of Whole-Slide Images of Sentinel and Targeted Lymph Node Frozen Sections in Breast Cancer

Different digital modalities are currently available for frozen section (FS) evaluation in surgical pathology practice. However, there are limited studies that demonstrate the potential of whole-slide imaging (WSI) as a robust digital pathology option for FS diagnosis. In the current study, we compared the diagnostic accuracy achieved with WSI to that achieved with light microscopy (LM) for evaluating FSs of axillary sentinel lymph nodes (SLNs) and clipped lymph nodes (LNs) from patients with breast cancer using 2 modalities. Initially, a retrospective analysis evaluated hematoxylin and eosin (H&E)-stained FSs of 109 SLNs using WSI followed by LM after a washout period ranging from 2 to 6 weeks. Subsequently, a prospective analysis assessed FSs of 132 SLNs using LM by the first pathologist, and then H&E-stained FSs were scanned and interpreted remotely in real time by a different pathologist. In the retrospective analysis, the diagnostic accuracy utilizing WSI ranged from 96% to 99% and exhibited similarity to those achieved with LM, ranging from 94% to 99%. Similarly, the prospective analysis also demonstrated comparable diagnostic accuracy between WSI (96.2%) and LM (97%). Pathologists in the retrospective study required an additional 0.8 to 5.4 minutes to render diagnoses using WSI compared with LM (P < .0001). In the prospective study conducted 2 years later, pathologists only took slightly longer to provide WSI FS diagnoses (3.95 minutes) compared with LM (3.51 minutes) (P > .05). In conclusion, our study indicated that WSI-based evaluation showed comparable diagnostic accuracy to LM for assessing LN FSs. Furthermore, the prospective study demonstrated the feasibility of real-time acquisition of high-quality WSIs for remote FS diagnosis of SLNs. These findings substantiate the promising potential of using WSIs of SLNs and clipped LNs in real-time FS evaluation of patients with breast cancer as a standard-of-care in surgical pathology practice.