Multifocality as a Marker of Aggressiveness in Medullary Thyroid Carcinoma: A Retrospective Cohort Analysis of Lymph Node Metastasis and Recurrence

Multifocal MTC exhibits aggressive behavior with high LNM and recurrence risks, driven by the number of tumor foci, demonstrating a dose-response relationship. These findings support incorporating multifocality into risk stratification for optimized management.Implications for Practice This study reveals that the number of tumor foci in medullary thyroid cancer (MTC) directly correlates with recurrence risk, establishing the first dose-response relationship. Patients with multifocal tumors show significantly worse progression-free survival (p < 0.001), providing evidence to guide postoperative surveillance intervals. These findings advance precision oncology by proposing the integration of multifocality into AJCC staging and clinical decision-making, offering a practical tool to optimize individualized patient management.