Background: Preoperative assessment is critical to decide the most adequate surgical strategy for oral squamous cell carcinoma (SCC). Magnetic resonance (MR) and intraoral ultrasonography (US) have been reported to be of great value for preoperative estimation of depth of invasion (DOI) and/or tumor thickness (TT). This review aims to analyze the accuracy of MR and intraoral US in determining DOI/TT in oral SCC, by assuming histological evaluation as the reference method.

Methods: The procedure was conducted following the modified 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. We performed a systematic search of papers on PubMed, Scopus, Web of Science, and Cochrane Library databases until July 31st, 2019. For quantitative synthesis, we included nine studies (487 patients) focused on MR, and 12 (520 patients) focused on intraoral US. The Pearson correlation coefficient (r) between DOI/TT evaluated with MR or intraoral US was assumed as effect size. A meta-analysis (MA) for each study group (MR and US) was performed by using the random-effects models with the DerSimonian–Laird estimator and r-to-z transformation.

Results: In the MA for MR studies, a high heterogeneity was found (I2 = 94.84%; Q = 154.915, P < 0.001). No significant risk of bias occurred by evaluating funnel plot asymmetry (P = 0.563). The pooled (overall) r of the MR studies was 0.87 (95% CI from 0.82 to 0.92), whereas the pooled r-to-z transformed was 1.44 (95% CI from 1.02 to 1.85). In the MA for US studies a high heterogeneity was found (I2 = 93.56%; Q = 170.884, P < 0.001). However, no significant risk of bias occurred (P = 0.779). The pooled r of the US studies was 0.96 (95% CI from 0.94 to 0.97), whereas the pooled r-to-z transformed was 1.76 (95% CI from 1.39 to 2.13). These outputs were confirmed in additional MA performed by enrolling only MR (n = 8) and US (n = 11) studies that evaluated TT.

Conclusions: MR and intraoral US seem to be promising approaches for preoperative assessment of DOI/TT in oral SCC. Remarkably, a higher pooled r and r-to-z transformed were observed in the intraoral US studies, suggesting that this approach could be more closely related to histopathological findings.

Magnetic Resonance vs. Intraoral Ultrasonography in the Preoperative Assessment of Oral Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis.

There is currently no standardized approach for assessing the depth of invasion (DOI) of oral tongue squamous cell carcinoma via diagnostic imaging. We investigated the usefulness of contrast-enhanced computed tomography (CECT) for estimating the pathological DOI of oral tongue squamous cell carcinoma by evaluating the correlation of pathological DOI with the DOIs on CECT and magnetic resonance imaging (MRI). We retrospectively reviewed 21 of 139 patients who underwent radical surgery for primary oral tongue squamous cell carcinoma between 2009 and 2018. The 21 cases were evaluable, without dental artifacts on CECT. DOIs on CECT and MRI, and pathological DOI were measured. The median pathological DOI was 9 mm, that on CECT was 10.9 mm, that on T2-weighted MRI was 14.2 mm, and that on contrast-enhanced T1-weighted MRI was 13.1 mm. The DOIs on CECT and on MRI were larger than the pathological DOI (p = 0.003 to < 0.001). The absolute value of the difference between pathological DOI and DOI on CECT was smaller than that between pathological DOI and DOI on MRI (p = 0.01 and 0.003). DOIs on CECT and on MRI correlated with pathological DOI (r = 0.74–0.66, all p < 0.001). Spearman’s correlation coefficient between DOI on CECT and pathological DOI was greater than that between DOI on MRI and pathological DOI. Compared to the DOI determined on an MRI scan, the DOI determined on a CECT scan correlated with and better approximated pathological DOI. Therefore, CECT can be useful for preoperative staging of patients with oral tongue squamous cell carcinoma.

Usefulness of contrast-enhanced CT in the evaluation of depth of invasion in oral tongue squamous cell carcinoma: comparison with MRI

The management of patients with early stage (cT1–T2) tongue squamous cell carcinoma without clinicoradiologic evidence of neck node metastasis (cN0) has been widely debated over the last 3 decades and still remains controversial. Nevertheless, the identification of patients with low-stage tumours at high-risk for occult cervical metastases is imperative before planning treatments of primary tumours, as well as that of prognostic markers which may possibly select those patients who may benefit of additional workup after surgery in view of the high metastatic potential of the primary tumour. The pre-surgical evaluation of tongue malignant primary tumour (for assessing lateral and deep margins) along with diode laser surgery (with accurate incision, bleeding-free and with reduced/absent post-surgical complications) may lead to a more conservative but equally decisive surgical treatment, also with a greater patient compliance. We studied 85 consecutive cases of cT1–T2 N0 tongue squamous cell carcinoma who had been managed by the following diagnostic/therapeutic protocol: pre-operative high definition ultrasound examination for the evaluation of size and depth, followed by three-dimensional surgical excision by diode laser (wavelength of 800 ± 10 nm, output power of 8 W in continuous wave, flexible optic fibre of 320 μm in contact mode) and detailed histological analyses of well-established prognostic parameters (tumour grade, thickness, depth, front of infiltration and surgical margins) with statistical analysis. No post-surgical photobiomodulation was performed. Overall, 58.82% of patients were stage I, 18% stage II, and the most frequent histotype was squamous cell carcinoma (97.64%). Large nests invasion pattern was observed in 64 cases, expansive pattern in 9, invasion in single cells in 12; front of invasion involved the muscle in 62 cases, vessels in 6, nerves in 15; peritumoural vascular invasion was assessed in 6 patients and perineural invasion in 15. Selective neck lymphadenectomy was performed in 9 cases, and clinically occult node metastases were detected in two cases. At follow-up, 78 patients (98.73%) were alive and free of disease, one patient experienced tumour-related death, while the remaining 6 died for non-disease-related causes. All the histological prognostic parameters were statistically significant (χ2 test; p = 0.05), thus leading to a prognostic weight classification with a three-tiered stratification. On the bases of these results, the authors maintain that the reported diagnostic/therapeutic protocol, including the pre-operative echo-guided three-dimensional evaluation, the following diode laser mini-invasive surgery for tumour excision and the histological examination along with the proposed three-tiered stratification of histological prognostic parameters may allow proper management of clinical stage I and II early tongue carcinomas.

Early tongue carcinomas (clinical stage I and II): echo-guided three-dimensional diode laser mini-invasive surgery with evaluation of histological prognostic parameters. A study of 85 cases with prolonged follow-up.

Depth of invasion (DOI) can be calculated preoperatively by MRI, and whether MRI-determined DOI can predict prognosis as well as whether it can be used as an indicator of neck dissection in cT1N0 tongue squamous cell carcinoma (SCC) remains unknown. The main goal of the current study was to answer these unknowns. A total of 151 patients with surgically treated cT1N0 tongue SCC were retrospectively enrolled, and MRI-determined DOI was measured based on T1-weighted layers with a 3.0T scan. The Chi-square test was used to evaluate the association between clinical pathologic variables and neck lymph node metastasis, and the factors that were significant in the Chi-square test were then analyzed in a multivariate logistic regression analysis model to determine the independent predictors. The main study endpoints were locoregional control (LRC) and disease-specific survival (DSS), and the Kaplan-Meier method (log-rank test) was used to calculate the LRC and DSS rates. The factors that were significant in univariate analysis were then analyzed in the Cox model to determine the independent prognostic factors. A value of p < 0.05 was considered significant, and all statistical analyses were performed with SPSS 20.0. Occult neck lymph node metastasis was noted in 26 (17.2%) patients, and the ROC curve indicated that the optimal cutoff value of MRI-determined DOI was 7.5 mm for predicting neck lymph node metastasis, with a sensitivity of 86.9%. The factors of lymphovascular invasion, MRI-determined DOI, pathologic DOI, and pathologic tumor grade were significantly associated with the presence of neck lymph node metastasis in univariate analysis, and further logistic regression analysis confirmed the independence of lymphovascular invasion, MRI-determined DOI, and pathologic DOI in predicting neck lymph node metastasis. The 5-year LRC and DSS rates were 84% and 90%, respectively. Cox model analysis suggested the MRI-determined DOI was an independent prognostic factor for both LRC and DSS. Therefore, elective neck dissection is suggested if MRI-determined DOI is greater than 7.5 mm in cT1N0 tongue SCC, and MRI-determined DOI ≥ 7.5 mm indicates additional risk for disease recurrence and cancer-related death.

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Significance of depth of invasion determined by MRI in cT1N0 tongue squamous cell carcinoma

BackgroundThe 8th edition of tumor, node, metastasis (TNM) classification incorporates depth of invasion evaluation in the staging of oral cavity squamous cell carcinoma, since it is a predictor of...

The role of MRI-derived depth of invasion in staging oral tongue squamous cell carcinoma: inter-reader and radiological-pathological agreement.

Objective Depth of invasion (DOI) in oral carcinoma has been integrated into the primary tumor categories in the current tumor-node-metastasis staging (8th edition). However, there is no standard modality to determine DOI preoperatively. The aims of the present study were to evaluate the accuracy of a preoperative measurement of DOI using ultrasonography (US) for superficial oral tongue carcinomas, and to correlate the values obtained with histologically determined DOI measurements. Methods We retrospectively analyzed the records of 56 patients with oral tongue carcinoma who underwent intraoral US preoperatively, followed by curative surgery at the Shizuoka Cancer Center Hospital in Japan. For the measurement of DOI with US, our unique technique (water balloon method) was evaluated. Results The histologically measured tumor size (maximum diameter) showed a distribution of 7.0 to 40.0 mm (mean, 18.6 mm). The correlation between the US-obtained and histologically obtained DOIs was significant (r = 0.867; P 5 mm were 92.3% and 70.6%, respectively. Conclusion Intraoral US provides sufficient accuracy for the measurement of tumor DOI in oral tongue carcinoma and is complementary in assessing superficial lesions. Level of evidence 4. Laryngoscope, 128:2778-2782, 2018.

Kotaro Morita

Papers

Depth of invasion in superficial oral tongue carcinoma quantified using intraoral ultrasonography.