MRI-derived tumor volume vs. pathological tumor diameter: a comparative study of prognostic value for disease-free survival in multifocal/multicentric breast cancer

Background and objective: Multifocal/multicentric breast cancer (MMBC) is characterized by multiple tumor foci in the same breast, but conventional T staging based on the largest lesion (Dmax) may underestimate true tumor burden. This study aimed to evaluate whether MRI-derived tumor volumes (Vmax and Vsum) provide superior prognostic value for disease-free survival (DFS) compared with pathological tumor diameters (Dmax and Dsum). Materials and methods: -transformed. Associations with DFS were assessed using Cox regression, and predictive performance was evaluated via Kaplan-Meier curves, receiver operating characteristic (ROC) analysis, and decision curve analysis (DCA). Results: (Dmax)), and DCA demonstrated greater net clinical benefit at threshold probabilities below 15.5%. Conclusions: MRI-derived sum of tumor volumes (Vsum) provides superior prognostic value for DFS in MMBC compared with diameter-based metrics. Integrating Vsum with lymph node burden may improve risk stratification and support personalized treatment planning.