CAT-WSI: Context-Aware Trajectory Learning for Whole-Slide Breast Pathology Segmentation

Computational analysis of breast histopathological images is critical for reliable computer-aided diagnosis and treatment planning. Owing to the ultra-high resolution of whole-slide images (WSIs), most existing WSI segmentation methods rely on patch-wise processing. However, independently processing isolated patches breaks spatial continuity and weakens global tissue context, ultimately limiting segmentation performance. To overcome these limitations, we propose CAT-WSI, a context-aware trajectory learning framework for breast pathology WSI segmentation. Rather than treating patches as unordered samples, CAT-WSI organizes them into structured transverse trajectories across each slide, thereby preserving long-range spatial dependencies while reducing the directional bias and boundary fragmentation inherent in conventional patch-based pipelines. To further enhance global positional awareness, CAT-WSI augments these trajectory representations with a paired downsampled whole-slide thumbnail, enabling explicit global-local contextual modeling over the entire slide. We evaluate CAT-WSI on the CAMELYON16 and Breast-HER2+ datasets across multiple magnification levels. Extensive experiments demonstrate that CAT-WSI achieves consistently strong performance across multiple magnification levels, attaining the best overall results on the evaluated benchmarks in our experimental setting.