Beyond the T: Volumetric MRI Predicts Lymphatic Spread in Oral Squamous Cell Carcinoma

Purpose: To assess the relationship between primary tumor volume, the spatial distribution of cervical lymph node metastases, and TNM (Tumor, node, metastasis) staging in patients with oral squamous cell carcinoma (OSCC) based on high-resolution MRI. Methods: This retrospective analysis evaluated 116 predominantly male (62.9%) patients (age 67.7 ± 11.5 years) with histologically confirmed OSCC who underwent surgical resection with neck dissection or definitive chemoradiation. MRI-based volumetry and center-to-center distance measurements between primary tumor and cervical lymph node metastases were performed using 3D postprocessing software. Results: Tumor-to-lymph node center-to-center distances ranged from 11.7 to 117.3 mm (median: 44.8 mm; interquartile range [IQR]: 32.1–59.6 mm). Primary tumor volume ranged from 0.5 to 87.2 cm3 (median: 13.3 cm3; IQR: 6.4–21.5 cm3) and was higher in male patients. A significant association was observed between tumor volume and both lymph node distance and pT-stage (p < 0.0001). The association between tumor volume and tumor–node distance was stronger (Spearman’s r = 0.4541, p < 0.0001) than that between pT-stage (TNM classification) and nodal distance (Spearman’s r coefficient =0.2682, p = 0.0036). Conclusion: MRI-based assessment indicated that tumor volume has a stronger association with the spatial extent of lymph node metastases compared with T-stage alone. Larger tumors were associated with greater distances to metastatic lymph nodes. These findings highlight the value of quantitative 3D MRI-based volume and distance analyses in potentially improving surgical and radiotherapeutic planning.