Abstract / Summary
Abstract Purpose In isocitrate dehydrogenase (IDH)-mutant diffuse glioma, extent of resection predicts survival, yet tumour infiltrates beyond imaging or visual inspection. Rapid intraoperative detection of IDH mutation status, its surrogate D-2-hydroxyglutarate (D-2HG), or signals may support residual-tumour assessment. Whether these technologies have progressed from tumour classification to margin decision support remains unclear. Methods Eligibility was defined using a Population–Concept–Context framework encompassing diffuse glioma tissue and models; intraoperatively feasible or proposed methods detecting IDH, D-2HG, or inferred IDH-linked outputs; and use for margin or infiltration assessment. Ovid MEDLINE, Ovid Embase, Web of Science, and Google Scholar were searched to 15 July 2026. Screening was performed independently in duplicate, and reporting followed PRISMA-ScR. Results Thirty-seven unique studies were included. Of 26 IDH-linked studies, 12 applied the readout spatially. No IDH-linked study established sensitivity or negative predictive value for local tumour presence at a sampled boundary site against an independent site-matched reference. Classification rules were largely derived from tumour-core or bulk tissue, while margin definitions and sampling workflows varied. Reported analysis times ranged from < 3 s for Raman to 100 min for PCR-based methods. Only two studies described further resection following a positive boundary result, and neither demonstrated attributable clinical benefit. Conclusion Intraoperative IDH detection has progressed from tumour classification to spatial application, but no validated molecular margin tool has been established. Translation requires boundary-specific validation: consistent spatial definitions, thresholds evaluated in low-cellularity tissue, and site-matched assessment of positive and negative results before they are used to guide further resection or stopping.