Preoperative evaluation of depth of invasion in oral tongue squamous cell carcinoma: A systematic review and meta-analysis

Accumulating evidence from meta-analyses of prognostic studies on oral cancer: towards biomarker-driven patient selection

BACKGROUND

Many histopathologic prognostic markers, identified by routine hematoxylin and eosin (HE) staining, have been proposed for predicting the survival of patients with oral squamous cell carcinoma (OSCC). Subsequently, several meta-analyses have been conducted on these prognostic markers. We sought to analyze the accumulated evidence from these meta-analyses.

METHODS

An electronic database search of PubMed, Scopus, Ovid Medline, Web of Science, and Cochrane Library was conducted to retrieve all meta-analysis articles published on histopathologic prognostic markers of OSCC. The risk of bias of the included studies was analyzed using the Risk of Bias in Systematic Reviews (ROBIS) tool. The synthesis of the results was conducted following the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

There were 16 meta-analysis articles published on the histological prognostic markers of OSSC. The accumulated evidence from these meta-analyses highlighted the powerful prognostic value of depth of invasion, tumor thickness, perineural invasion, lymphovascular invasion, worst pattern of invasion, tumor budding, and tumor-stroma ratio. The highest odds ratio (OR) of a relationship between a histopathologic prognostic marker and outcome was for the depth of invasion (OR 10.16, 95% CI 5.05-20.46) and tumor thickness (OR 7.32, 95% CI 5.3-10.1) in predicting lymph node metastasis.

CONCLUSION

The published meta-analyses present robust evidence on the significance of emerging histopathologic markers, namely, worst pattern of invasion, tumor budding, and tumor-stroma ratio. It is time to consider such markers in daily pathology reporting and risk stratification of OSCC.

Prognostic Effect of Patterns of Local Extension and Satellitosis in cT3 Squamous Cell Carcinoma of the Oral Tongue: A Prospective Observational Study

INTRODUCTION

The anatomy of the tongue is three-dimensionally complex and is thought to play a central role in the local growth of oral tongue squamous cell carcinoma (OTSCC). Understanding patterns of tumor extension could improve a multimodal therapeutic approach. Thus, the main aim of this study was to provide a histological and microanatomical analysis of surgical specimens after compartmental surgery for OTSCC.

MATERIALS AND METHODS

The present prospective observational study included primary cT3 OTSCC (according to the eighth edition of the TNM classification) treated in an academic tertiary referral center with curative compartmental surgery, from July 2016 to July 2019. Analysis of histologic macrosections allowed assessment of standard pathologic parameters as well as a detailed analysis of the position of OTSCC cells from microanatomic and topographic standpoints.

RESULTS

Of the 28 patients included, 71.4% were males, with a mean age of 64.9 years. Nine (32.1%) patients presented satellitosis, which was always located within the T-N tract. OTSCCs displaying satellitosis had a significantly higher median pathologic depth of invasion (DOI). A radiologic and pathological DOI > 15 mm significantly predicted the presence of satellites. There was a significant relationship between the presence of satellites and both positive lymph nodes and distant metastases.

CONCLUSION

Approximately one-third of cases of intermediate-to-advanced OTSCC are characterized by tumor satellites located in the T-N tract. DOI exceeding 15 mm and the presence of clinically appreciable nodal metastases best predict the presence of satellitosis. Satellite-bearing OTSCC behave more aggressively, with an increased risk of distant metastasis and reduced survival.

Pathological Risk Factors for Occult Nodal Metastasis in Early-Stage Squamous Cell Carcinoma of the Oral Cavity

Occult neck metastasis is the presence of metastasis in the cervical lymph nodes that cannot be radiologically or clinically identified. Presence of metastasis in any neck node can have a significant impact on overall survival of patients with oral squamous cell carcinoma (OSCC). Our aim was to analyze the correlation of various histopathological parameters with occult nodal metastasis in early-stage OSCC and to obtain an optimal DOI cut-off value for predicting its increased risk. We conducted a retrospective study on patients who reported to our institute with clinical stage I and II OSCC. The patients having well-differentiated and moderately differentiated OSCC were included. Association of various histopathological parameters with occult nodal metastasis was assessed using statistical analysis. A total of 102 patients of early-stage well-differentiated and moderately differentiated OSCC with clinically negative necks who underwent elective neck dissection at our institute from the year 2018 to 2023 were enrolled in the study. Depth of invasion (DOI), perineural invasion (PNI), worst pattern of invasion (WPOI), and grade of tumor differentiation were the histopathological parameters entered into the univariate regression analysis as predictive variables, and they were found to be predictors of occult nodal metastasis. An optimal DOI cut-off value of 5.5 mm was obtained for predicting the increase in the risk of occult nodal metastasis. DOI, PNI, WPOI, and grade of tumor differentiation are predictors of occult nodal metastasis. There is a need for searching methods for preoperative and intraoperative detection of all these histopathological factors so that unnecessary elective neck treatment can be avoided.

Value of radiological depth of invasion in non-pT4 Oral tongue squamous cell carcinoma: implication for preoperative MR T-staging

OBJECTIVE

The prognostic stratification for oral tongue squamous cell carcinoma (OTSCC) is heavily based on postoperative pathological depth of invasion (pDOI). This study aims to propose a preoperative MR T-staging system based on tumor size for non-pT4 OTSCC.

METHODS

Retrospectively, 280 patients with biopsy-confirmed, non-metastatic, pT1-3 OTSCC, treated between January 2010 and December 2017, were evaluated. Multiple MR sequences, including axial T2-weighted imaging (WI), unenhanced T1WI, and axial, fat-suppressed coronal, and sagittal contrast-enhanced (CE) T1WI, were utilized to measure radiological depth of invasion (rDOI), tumor thickness, and largest diameter. Intra-class correlation (ICC) and univariate and multivariate analyses were used to evaluate measurement reproducibility, and factors' significance, respectively. Cutoff values were established using an exhaustive method.

RESULTS

Intra-observer (ICC = 0.81-0.94) and inter-observer (ICC = 0.79-0.90) reliability were excellent for rDOI measurements, and all measurements were significantly associated with overall survival (OS) (all p < .001). Measuring the rDOI on axial CE-T1WI with cutoffs of 8 mm and 12 mm yielded an optimal MR T-staging system for rT1-3 disease (5-year OS of rT1 vs rT2 vs rT3: 94.0% vs 72.8% vs 57.5%). Using multivariate analyses, the proposed T-staging exhibited increasingly worse OS (hazard ratio of rT2 and rT3 versus rT1, 3.56 [1.35-9.6], p = .011; 4.33 [1.59-11.74], p = .004; respectively), which outperformed pathological T-staging based on nonoverlapping Kaplan-Meier curves and improved C-index (0.682 vs. 0.639, p < .001).

CONCLUSIONS

rDOI is a critical predictor of OTSCC mortality and facilitates preoperative prognostic stratification, which should be considered in future oral subsite MR T-staging.

CLINICAL RELEVANCE STATEMENT

Utilizing axial CE-T1WI, an MR T-staging system for non-pT4 OTSCC was developed by employing rDOI measurement with optimal thresholds of 8 mm and 12 mm, which is comparable with pathological staging and merits consideration in future preoperative oral subsite planning.

KEY POINTS

• Tumor morphology, measuring sequences, and observers could impact MR-derived measurements and compromise the consistency with histology. • MR-derived measurements, including radiological depth of invasion (rDOI), tumor thickness, and largest diameter, have a prognostic impact on OS (all p < .001). • rDOI with cutoffs of 8 mm and 12 mm on axial CE-T1WI is an optimal predictor of OS and could facilitate risk stratification in non-pT4 OTSCC disease.

Tumor thickness and depth of invasion in squamous cell carcinoma of tongue as indicators of the loco-regional spread of the disease: A preliminary study

Background

Magnetic resonance imaging (MRI) is a routinely used imaging modality for pre-treatment radiologic evaluation of tongue carcinoma, providing accurate information regarding the extent of the disease.

Aims and objectives

To investigate the role of MRI-derived depth of invasion and tumor thickness evaluation in squamous cell carcinoma of the tongue, and to assess if any correlation exists between depth of invasion, tumor thickness, nodal metastasis, muscles, and space involved.

Materials and methods

Thirty-three patients with oral squamous cell carcinoma of the tongue who had undergone pre-treatment MRI and excisional biopsy were included. The tumor thickness (TT) and depth of invasion (DOI) were evaluated on MRI and histopathologic images.

Result

The relation between different methodologies for assessing showed a very high correlation for the tumor tissue thickness (r = 0.99, p < 0.05) and depth of invasion (r = 0.82, p < 0.05). The tumor thickness and the depth of invasion increased with the loss of differentiation in the carcinoma histopathologically. As the depth of invasion increases, the extent of the spread of the carcinoma to tongue musculature, lingual septum, and spaces also increases.

Conclusion

The present study has depicted a high correlation between the tumor thickness and the depth of invasion between MRI and histopathological findings and is the first of its kind to correlate DOI to the invasiveness of the disease.

Prognostic value of radiological T category using conventional MRI in patients with oral tongue cancer: comparison with pathological T category

PURPOSE

This study aimed to compare the radiological tumor (T)-category using multiparametric MRI with the pathological T category in patients with oral tongue squamous cell carcinoma (OTSCC) and to examine which is a better predictor of prognosis.

METHODS

This retrospective study included 110 consecutive patients with surgically resected primary OTSCC who underwent preoperative contrast-enhanced MRI. T categories determined by maximum diameter and depth of invasion were retrospectively assessed based on the pathological specimen and multiparametric MRI. The MRI assessment included the axial and coronal T1-weighted image (T1WI), axial T2-weighted image (T2WI), coronal fat-suppressed T2WI, and axial and coronal fat-suppressed contrast-enhanced T1WI (CET1WI). Axial and coronal CET1WI measurements were divided into two groups: measurements excluding peritumoral enhancement (MEP) and measurements including peritumoral enhancement. The prognostic values for recurrence and disease-specific survival after radiological and pathological T categorization of cases into T1/T2 and T3/T4 groups were compared.

RESULTS

The T category of MEP on coronal CET1WI was the most relevant prognostic factor for recurrence [hazard ratio (HR) = 3.30, p = 0.001] and the HR was higher than the HR for pathological assessment (HR = 2.26, p = 0.026). The T category determined by MEP on coronal CET1WI was also the most relevant prognostic factor for disease-specific survival (HR = 3.12, p = 0.03), and the HR was higher than the HR for pathological assessment (HR = 2.02, p = 0.20).

CONCLUSION

The T category determined by MEP on the coronal CET1WI was the best prognostic factor among all radiological and pathological T category measurements.

SCUBE3 Exerts a Tumor-Promoting Effect in Tongue Squamous Cell Carcinoma by Promoting CEBPA Binding to the CCL2 Promoter

Tongue squamous cell carcinoma (TSCC) is the main pathologic subtype of oral cancer, and the current therapeutic effect is far from satisfactory. The signal peptide-CUB-EGF domain-containing protein 3 (SCUBE3) has been shown to be a tumor-promoting factor in several malignancies. However, little is known about the role of SCUBE3 in TSCC. In this study, we identified that SCUBE3 was highly expressed in TSCC. Clinically, high expression of SCUBE3 was positively associated with tumor stage and T stage of TSCC. Functionally, SCUBE3 silence remarkably restrained cell proliferation, migration, and invasion, induced apoptosis as well as cell cycle arrest in G2-phase, and weakened the tumorigenicity of TSCC cells in vivo. Mechanistically, SCUBE3 promoted the direct binding of CCAAT enhancer binding protein alpha (CEBPA) to C-C motif chemokine ligand 2 (CCL2) promoter in TSCC cells. Interestingly, CCL2 overexpression partially reversed the inhibitory effect of SCUBE3 deficiency on TSCC cell viability and migration. Moreover, STAT3 signaling contributed to CCL2-mediated phenotypes in TSCC cells.

IMPLICATIONS

Our data revealed a tumor-promoting role for SCUBE3 in TSCC via the CEBPA/CCL2/STAT3 axis, which provided new insight into novel potential therapeutic target for TSCC.

Implementing a deep learning model for automatic tongue tumour segmentation in ex-vivo 3-dimensional ultrasound volumes

Three-dimensional (3D) ultrasound can assess the margins of resected tongue carcinoma during surgery. Manual segmentation (MS) is time-consuming, labour-intensive, and subject to operator variability. This study aims to investigate use of a 3D deep learning model for fast intraoperative segmentation of tongue carcinoma in 3D ultrasound volumes. Additionally, it investigates the clinical effect of automatic segmentation. A 3D No New U-Net (nnUNet) was trained on 113 manually annotated ultrasound volumes of resected tongue carcinoma. The model was implemented on a mobile workstation and clinically validated on 16 prospectively included tongue carcinoma patients. Different prediction settings were investigated. Automatic segmentations with multiple islands were adjusted by selecting the best-representing island. The final margin status (FMS) based on automatic, semi-automatic, and manual segmentation was computed and compared with the histopathological margin. The standard 3D nnUNet resulted in the best-performing automatic segmentation with a mean (SD) Dice volumetric score of 0.65 (0.30), Dice surface score of 0.73 (0.26), average surface distance of 0.44 (0.61) mm, Hausdorff distance of 6.65 (8.84) mm, and prediction time of 8 seconds. FMS based on automatic segmentation had a low correlation with histopathology (r = 0.12, p = 0.67); MS resulted in a moderate but insignificant correlation with histopathology (r = 0.4, p = 0.12, n = 16). Implementing the 3D nnUNet yielded fast, automatic segmentation of tongue carcinoma in 3D ultrasound volumes. Correlation between FMS and histopathology obtained from these segmentations was lower than the moderate correlation between MS and histopathology.

Intraoral Ultrasound versus MRI for Depth of Invasion Measurement in Oral Tongue Squamous Cell Carcinoma: A Prospective Diagnostic Accuracy Study

Oral squamous cell carcinoma (OSCC) of the tongue is the most common type of oral cavity cancer, and tumor depth of invasion (DOI) is an important prognostic factor. In this study, we investigated the accuracy of intraoral ultrasound and magnetic resonance imaging (MRI) for assessing DOI in patients with OSCC. Histopathological measurement of DOI was used as a reference standard. We conducted a prospective study including patients planned for surgical treatment of OSCC in the tongue. The DOI was measured in an outpatient setting by intraoral ultrasound and MRI, and was compared to the histopathological DOI measurements. Bland-Altman analysis compared the mean difference and 95% limits of agreement (LOA) for ultrasound and MRI, and the Wilcoxon signed-rank test was used to test for significance. The correlation was evaluated using Pearson's correlation coefficient. We included 30 patients: 26 with T1 or T2 tumors, and 4 with T3 tumors. The mean difference from histopathology DOI was significantly lower for ultrasound compared to MRI (0.95 mm [95% LOA -4.15 mm to 6.06 mm] vs. 1.90 mm [95% LOA -9.02 mm and 12.81 mm], p = 0.023). Ultrasound also led to significantly more correct T-stage classifications in 86.7% (26) of patients compared to 56.7% (17) for MRI, p = 0.015. The Pearson correlation between MRI and histopathology was 0.57 (p < 0.001) and the correlation between ultrasound and histopathology was 0.86 (p < 0.001). This prospective study found that intraoral ultrasound is more accurate than MRI in assessing DOI and for the T-staging of oral tongue cancers. Clinical practice and guidelines should implement intraoral ultrasound accordingly.

Single-cell RNA sequencing reveals the heterogeneity of epithelial cell and fibroblast cells from non- to metastatic lymph node OTSCC

Lymph node metastasis (LNM) is one of the common features of oral tongue squamous cell carcinoma (OTSCC). LNM is also taken as a sign of advanced OTSCC and poor survival rate. Recently, single-cell RNA sequencing has been applied in investigating the heterogeneity of tumor microenvironment and discovering the potential biomarkers for helping the diagnosis and prognosticating. Pathogenesis of LNM in OTSCC remains unknown. Specifically, cancer-associated fibroblasts (CAFs) and epithelial tumor cells could foster the progression of tumors. Thus, in this study, we aimed to comprehensively analyze the roles of subpopulations of CAFs and epithelial tumor cells in lymph node metastatic OTSCC using the integration of OTSCC single-cell RNA sequencing datasets. Four distinct subtypes of CAFs, namely vascular CAFs, myofibroblast CAFs, inflammatory CAFs, and growth arrest CAFs were successfully discovered in LNM tumor and confirmed the roles of GAS and PTN pathways in the progression of tumor metastasis. In addition, NKAIN2+ epithelial cells and FN1+ epithelial cells specifically exhibited an upregulation of PTN, NRG, MIF, and SPP1 signaling pathways in the metastatic OTSCC. In doing so, we put forth some potential biomarkers that could be utilized for the purpose of diagnosing and prognosticating OTSCC during its metastatic phase and tried to confirm by immunofluorescence assays.

Comparison of the 8th edition of TNM staging of oral cancer with the 7th edition and its prognostic significance using clinical depth of invasion and extranodal extension

OBJECTIVES

The 8th edition of the International Union Against Cancer Control/American Joint Committee on Cancer Staging System introduced depth of invasion (DOI) and extranodal extension (ENE) into the staging of oral cavity cancer. We evaluated the prognostic ability of this new staging system compared with the 7th edition using clinical DOI (cDOI) and clinical ENE (cENE).

MATERIALS AND METHODS

We retrospectively reviewed and restaged 2,118 patients with oral squamous cell carcinoma treated between 2001 and 2018 using cDOI and cENE. Overall and disease-specific survival were used as endpoints to compare the prognostic outcomes of the 7th and 8th editions using Harrell's concordance index (C-index).

RESULTS

In total, 305 (14.4 %) cases were upstaged in the T category, 85 (4.0 %) cases were upstaged in the N category, and 280 (13.2 %) cases were upstaged in the overall TNM stage. The introduction of the cDOI increased the C-index and hazard ratio (HR) for each T category. The introduction of cENE increased the N3b category of 85 cases, bringing the total to 94 cases, thereby widening the differences between each N category. In the 8th edition, the C-index and HR for overall TNM stage increased, and the discrimination between stage groups improved.

CONCLUSIONS

The 8th edition of the TNM clinical staging system using cDOI and cENE predominantly identified patients with a high mortality rate, thus improving the ability to discriminate and prognosticate oral cancer.

Can High-Frequency Intraoral Ultrasound Predict Histological Risk Factors in Oral Squamous Cell Carcinoma? A Preliminary Experience

Despite advancements in multidisciplinary care, oncologic outcomes of oral cavity squamous cell carcinoma (OSCC) have not substantially improved: still, one-third of patients affected by stage I and II can develop locoregional recurrences. Imaging plays a pivotal role in preoperative staging of OSCC, providing depth of invasion (DOI) measurements. However, locoregional recurrences have a strong association with adverse histopathological factors not included in the staging system, and any imaging features linked to them have been lacking. In this study, the possibility to predict histological risk factors in OSCC with high-frequency intraoral ultrasonography (IOUS) was evaluated. Thirty-four patients were enrolled. The agreement between ultrasonographic and pathological DOI was evaluated, and ultrasonographic margins' appearance was compared to the Brandwein-Gensler score and the worst pattern of invasion (WPOI). Excellent agreement between ultrasonographic and pathological DOI was found (mean difference: 0.2 mm). A significant relationship was found between ultrasonographic morphology of the front of infiltration and both Brandwein-Gensler score ≥ 3 (p < 0.0001) and WPOI ≥4 (p = 0.0001). Sensitivity, specificity, positive predictive value, and negative predictive value for the IOUS to predict a Brandwein-Gensler score ≥3 were 93.33%, 89.47%, 87.50%, and 94.44%, respectively. The present study demonstrated the promising role of IOUS in aiding risk stratification for OSCC patients.

Magnetic resonance imaging-based prediction models for tumor stage and cervical lymph node metastasis of tongue squamous cell carcinoma

Purpose

To evaluate the ability of preoperative MRI-based measurements to predict the pathological T (pT) stage and cervical lymph node metastasis (CLNM) via machine learning (ML)-driven models trained in oral tongue squamous cell carcinoma (OTSCC).

Materials and methods

108 patients with a new diagnosis of OTSCC were enrolled. The preoperative MRI study included post-contrast high-resolution T1-weighted images acquired in all patients. MRI-based depth of invasion (DOI) and tumor dimension-together with shape-based and intensity-based features-were extracted from the lesion volume segmentation. The entire dataset was randomly divided into a training set and a validation set, and the performances of different types of ML algorithms were evaluated and compared.

Results

MRI-based DOI and tumor dimension together with several shape-based and intensity-based signatures significantly discriminated the pT stage and LN status. The overall accuracy of the model for predicting the pT stage was 0.86 (95%CI, 0.78-0.92) and 0.81 (0.64-0.91) in the training and validation sets, respectively. There was no improvement in the model performance upon including shape-based and intensity-based features. The model for predicting CLNM based on DOI and tumor dimensions had a fair accuracy of 0.68 (0.57-0.78) and 0.69 (0.51-0.84) in the training and validation sets, respectively. The shape-based and intensity-based signatures have shown potential for improving the model sensitivity, with a comparable accuracy.

Conclusion

MRI-based models driven by ML algorithms could stratify patients with OTSCC according to the pT stages. They had a moderate ability to predict cervical lymph node metastasis.

Should an elective contralateral neck dissection be performed in midline-reaching squamous cell carcinomas of the oral cavity and oropharynx?

OBJECTIVE

to compare the rate of occult contralateral neck metastases (OCNM) in oral and oropharyngeal squamous cell carcinomas (SCC) reaching or crossing the midline and to identify risk factors for OCNM.

MATERIALS AND METHODS

we conducted a single-center retrospective study of oral and oropharyngeal SCC with contralateral cN0 neck. The cohort was divided into a midline-reaching (MR; approaching the midline from up to 10 mm) group and a midline-crossing (MC; exceeding the midline by up to 10 mm) group. Clinical N-status was assessed by a radiologist specializing in head and neck imaging. All patients underwent contralateral elective neck dissection (END).

RESULTS

A total of 98 patients were included in this study, 59 in the MR group and 39 in the MC group. OCNM were present in 17.3% of patients, 20.3% in the MR group and 12.8% in the MC group (p = 0.336). In multivariable analysis, MR/MC status as well as distance from the midline (in mm) were not identified as risk factors for OCNM. Conversely, oropharyngeal primary and clinical N-status above N1 were significantly associated with a higher risk of OCNM, with odds ratios (OR) of 3.98 (95% CI = 1.08-14.60; p = 0.037) and 3.41 (95% CI = 1.07-10.85; p = 0.038) respectively.

CONCLUSION

in patients with oral and oropharyngeal SCC extending close to or beyond the midline, tumor origin and clinical N-status should carry the most weight when dictating the indications for contralateral END, rather than the midline involvement in itself.

Image-Guided Intraoperative Assessment of Surgical Margins in Oral Cavity Squamous Cell Cancer: A Diagnostic Test Accuracy Review

(1) Background: The assessment of resection margins during surgery of oral cavity squamous cell cancer (OCSCC) dramatically impacts the prognosis of the patient as well as the need for adjuvant treatment in the future. Currently there is an unmet need to improve OCSCC surgical margins which appear to be involved in around 45% cases. Intraoperative imaging techniques, magnetic resonance imaging (MRI) and intraoral ultrasound (ioUS), have emerged as promising tools in guiding surgical resection, although the number of studies available on this subject is still low. The aim of this diagnostic test accuracy (DTA) review is to investigate the accuracy of intraoperative imaging in the assessment of OCSCC margins. (2) Methods: By using the Cochrane-supported platform Review Manager version 5.4, a systematic search was performed on the online databases MEDLINE-EMBASE-CENTRAL using the keywords "oral cavity cancer, squamous cell carcinoma, tongue cancer, surgical margins, magnetic resonance imaging, intraoperative, intra-oral ultrasound". (3) Results: Ten papers were identified for full-text analysis. The negative predictive value (cutoff < 5 mm) for ioUS ranged from 0.55 to 0.91, that of MRI ranged from 0.5 to 0.91; accuracy analysis performed on four selected studies showed a sensitivity ranging from 0.07 to 0.75 and specificity ranging from 0.81 to 1. Image guidance allowed for a mean improvement in free margin resection of 35%. (4) Conclusions: IoUS shows comparable accuracy to that of ex vivo MRI for the assessment of close and involved surgical margins, and should be preferred as the more affordable and reproducible technique. Both techniques showed higher diagnostic yield if applied to early OCSCC (T1-T2 stages), and when histology is favorable.