# Staging of oral cavity cancer in the 8th edition of the TNM classification: The role of computed tomography in the assessment of depth of invasion and extranodal extension

## TL;DR

This study shows that computed tomography can accurately assess tumor depth and staging in oral cavity cancer, aligning with pathological findings.

## Contribution

The study validates pre-surgical CT evaluation criteria for oral cavity cancer based on pathological depth of invasion standards.

## Key findings

- CT with venous contrast correlates strongly with tumor thickness and depth of invasion at pathology.
- Tomographic evaluation upstaged most lesions under both TNM-7 and TNM-8 criteria.
- Moderate correlation was found between tomographic and pathological T classifications for tumor thickness and DOI.

## Abstract

•Strong positive correlation between tumor thickness and tomographic depth of invasion.•Positive correlation between tomographic tumor thickness and pathological tumor thickness.•Positive correlation between tomographic depth of invasion and pathological depth of invasion.•Tomographic evaluation of deep of invasion upstaged most of lesions.

Strong positive correlation between tumor thickness and tomographic depth of invasion.

Positive correlation between tomographic tumor thickness and pathological tumor thickness.

Positive correlation between tomographic depth of invasion and pathological depth of invasion.

Tomographic evaluation of deep of invasion upstaged most of lesions.

Suggest and validate pre-surgical tomographic evaluation criteria for OCC based on the pathological DOI criteria.

A retrospective cohort study was conducted with 80 patients with tongue and floor of mouth tumors, T1 and T2, followed from 2009 to 2015. Patients were initially classified according to the 7th edition of the TNM (TNM-7) using pathological samples and then reclassified based on the updated 8th edition of the TNM (TNM-8) criteria. The same was done radiologically, using extrapolation and adaptation of the pathological criteria to tomographic evaluation. The results of pathological staging were compared and correlated with the main clinical outcomes. The same was done with the radiological results. To evaluate the pre-surgical accuracy of tomographic staging, radiological and pathological results were compared.

Regardless of the criteria (TNM-7 or TNM-8), it was observed that Computed Tomography (CT) with venous contrast may be used to guide the initial staging. Strong positive correlation was observed between tumor thickness and DOI at both CT and pathology. Considerable upstaging was observed in the sample of assessed patients for both criteria. In the comparison between tomographic and pathological T classifications, moderate correlation was observed in relation to thickness and DOI.

Computed tomography can be used to evaluate the depth of preoperative invasion in oral cavity tumors according to the criteria established in the present study.

Level III.