DARE-FUSE: domain aligned evidence guided learning for joint brain tumor MRI segmentation and classification

Brain tumor MRI segmentation and classification are essential for preoperative boundary assessment, lesion burden quantification, postoperative response monitoring, and radiotherapy planning, yet edema overlap, sequence heterogeneity, and artifacts often blur lesion margins. Together with the high cost of pixel-level annotation, these factors limit robust, cross-institution deployment. We propose DARE-FUSE (Domain Aligned Representation with Evidence-guided FUSE), a unified framework for pixel-level segmentation and image-level classification under limited samples and labels. Dual encoders with a feature-interaction bridge learn a shared embedding, and a Domain Alignment Refiner maps it to task-aligned representations for the segmentation and classification branches. For segmentation, U-SEG decodes features and SEGU outputs pixel-wise uncertainty to regularize boundary over/under-segmentation. For classification, CPG produces predictions and multi-scale Grad-CAM++ evidence. A Generative Lesion Removal Prior reconstructs a tumor-free counterpart to yield a difference prior, and FUSE combines this prior with Grad-CAM++ under uncertainty attenuation to guide segmentation and suppress hallucinations. DARE-FUSE achieves stable, leading performance on BraTS segmentation benchmarks and several classification datasets; ablations and label-reduction experiments confirm complementary gains and smooth degradation as pixel annotations decrease. The resulting uncertainty maps and continuous priors support interpretable decision assistance in surgery, radiotherapy contouring, triage, and longitudinal follow-up.