Pre-operative magnetic resonance imaging for evaluating depth of invasion in oral tongue cancer: Precision and predictive value.

Background

Accurate evaluation of the depth of invasion (DOI) in oral tongue squamous cell carcinoma (OTSCC) is essential for staging and treatment planning. Magnetic resonance imaging (MRI) is increasingly used as a non-invasive method for preoperative DOI assessment, though further validation against histopathology is needed.

Aim

This study aims to assess the precision and predictive value of MRI-derived DOI in preoperative evaluation of oral tongue cancer.

Methods

Thirty-two patients underwent preoperative MRI, providing sufficient power to detect a strong correlation with pathological DOI (pDOI) (80% power, α = 0.05). DOI measurements were obtained from axial and coronal MRI sequences and compared to pDOI from postoperative histopathology. Accuracy of MRI-derived DOI was assessed against tumor staging and pathological parameters.

Results

MRI-derived depth of invasion (rDOI) strongly correlated with pDOI, achieving a correlation coefficient of 0.89. MRI showed 81.3% accuracy in DOI-based staging, with high concordance in T1 and T4a tumors, but lower accuracy for intermediate lesions (DOI 5-10 mm). Factors significantly affecting rDOI accuracy included tumor morphology, boundary clarity, size, cervical nodal status, and invasiveness on MRI. ROC analysis demonstrated high predictive value for muscle invasion (optimal rDOI: 7.0 mm), moderate accuracy for perineural invasion (8.6 mm), and good prediction of nodal metastasis (10 mm). However, rDOI had limited sensitivity for detecting lymphovascular invasion.

Conclusions

MRI-based DOI provides a reliable, non-invasive tool for preoperative assessment of OTSCC, with strong correlation to pathological findings. While effective in detecting local invasion and nodal risk, overestimation in intermediate-stage tumors warrants cautious interpretation in treatment-decision.