Intraoral ultrasonography in the assessment of DOI in oral cavity squamous cell carcinoma: a comparison with magnetic resonance and histopathology

Abstract

Objective: The first-line therapeutic approach for oral cavity squamous cell carcinoma (OCSCC) is complete surgical resection. Preoperative assessment of depth of invasion (cDOI) is crucial to plan the surgery. Magnetic resonance (MR) and intraoral ultrasonography (IOUS) have been shown to be useful tools for assessment of DOI. The present analysis investigates the accuracy of MR and IOUS in evaluating DOI in OCSCC compared to histological evaluation (pDOI).

Materials and methods: Forty-nine previously untreated patients with cT1-T3 OCSCC were reviewed. Nine patients were staged with MR alone, 10 with IOUS alone, and 30 with both MR and IOUS.

Results: Mean difference between cDOI_MR and pDOI values of 0.2 mm (95% CI - 1.0-1.3 mm) and between cDOI_IOUS and pDOI of 0.3 mm (95% CI - 1.0-1.6 mm). Spearman R between cDOI_MR and pDOI was R = 0.83 and between cDOI_IOUS and pDOI was R = 0.76. Both radiological techniques showed high performance for the correct identification, with the optimum cut-off of 5 mm, of patients with a pDOI ≥ 4 mm and amenable to a neck dissection, with an AUC of 0.92 and 0.82 for MR and IOUS, respectively.

Conclusion: Both examinations were valid approaches for preoperative determination of DOI in OCSCC, although with different cost-effectiveness profiles and indications.

Keywords: Depth of invasion; Head and neck; Magnetic resonance imaging; Mouth; Neoplasm; Ultrasonography.

Fig. 1

Coronal-reformatted 3D T1-GRE acquisition showing an ulcerated squamous cell carcinoma of the oral tongue. cDOI_MR was measured (blue dashed line) perpendicularly to the mucosal plane (red dashed line)

Fig. 2

a DOI estimation (blue dashed line) in an exophytic SCC of the lateral border of the oral tongue. b Estimation of cDOI_IOUS in tongue carcinoma (blue dashed line). The dashed grey line represents the mucosal plane. The lesion was ulcerated: in such cases, a small amount of gel may be helpful to prevent air artifacts

Fig. 3

Scatter plots showing the comparisons of pDOI with cDOI_MR (a) or cDOI_IOUS (b) and between cDOI_MR and cDOI_IOUS (c); plotted black linear regression line with 95% CI bands in shadow gray; pT categories reported. Box plots showing paired DOI measures (d) and violin plots reporting differences distributions comparing the DOI assessed by different techniques

Fig. 4

a Plot showing the sensitivity and specificity changes, related to the correct detection of a pDOI ≥ 4 mm along with the variation of the cut-off for cDOI_MR or cDOI_IOUS.. b Receiver operating characteristic (ROC) curve of cDOI_MR of cDOI_IOUS for pDOI ≥ 4 mm prediction showing the cut-off point of 5 mm for both techniques, by maximization of Youden’s index. c Plots showing the distribution of cDOI_MR and cDOI_IOUS in pDOI ≥ or < 4 mm groups, black vertical line at 5 mm of cDOI