Radiologic 3D tumor volume predicts cervical metastasis in oral squamous cell carcinoma.

OBJECTIVES

To test whether pre-operative primary CT-based 3D tumor volume (TV) improves prediction of cervical spread in oral squamous cell carcinoma (OSCC) beyond conventional size metrics.

MATERIALS AND

METHODS

We retrospectively analyzed 132 consecutive primary OSCC patients (2014-2019). Contrast-enhanced CT datasets were semi-automatically segmented to obtain 3D TV (cm3), verified by a second observer. Multivariable logistic regression related log-TV to pathologic lymph-node metastasis (LNM), extranodal extension (ENE), and skip metastasis. Performance of radiologic TV, depth of invasion (DOI), and ellipsoid pathologic volume was compared by ROC/AUC and decision-curve analyses.

RESULTS

Median CT-derived TV was 12.6 cm3. Log-TV independently predicted LNM (odds ratio 3.00, 95% CI 1.21-7.68; AUC 0.815), outperforming DOI (AUC 0.541) and pathologic volume (AUC 0.498). A non-linear pattern linked very small (< 1.8 cm3) and large (> 16 cm3) tumors to increased skip-metastasis probability (AUC 0.733). Radiologic and pathologic volumes showed minimal concordance (R2 = 0.0002). Decision-curve analysis demonstrated consistent net benefit of the volume model across clinically relevant threshold probabilities for elective neck dissection.

CONCLUSIONS

CT-based 3D volumetry is an independent pre-operative predictor of cervical LNM, flags tumors prone to skip spread, and offers greater clinical utility than linear measures.

CLINICAL RELEVANCE: Integrating radiologic volumetry into staging could refine nodal management-particularly in clinically node-negative patients-by supporting risk-adapted selection between sentinel lymph-node biopsy and elective neck dissection; prospective validation is warranted.