Reliability of MRI-Derived Depth of Invasion of Oral Tongue Cancer

MRI and frozen section evaluation of mylohyoid muscle in determining surgical approach for T2-T3 floor of the mouth cancer

PURPOSE

The choice of surgical approach for floor of the mouth (FOM) cancer, particularly for intermediate-stage tumors (cT2-cT3), remains controversial. This study aims to evaluate a method considering mylohyoid muscle (MM) invasion as a determinant for surgical approach selection, utilizing magnetic resonance imaging (MRI) preoperatively and frozen section (FS) analysis intraoperatively.

METHODS

This observational retrospective cohort study analyzed patients undergoing surgical resection of cT2 and cT3 FOM squamous cell carcinoma (SCC) between January 2013 and June 2023. MM infiltration assessed by preoperative MRI determined the surgical approach: clear infiltration led to compartmental surgery (CS), while doubtful or absent infiltration led to transoral surgery (TOS). Conversion from TOS to CS occurred intraoperatively based on macroscopic evidence or positive FS. Data collected included demographic, clinical, surgical, and pathological variables. Survival analysis was conducted using Kaplan-Meier method.

RESULTS

Among 44 patients included, majority had cT2 tumors (59.1%). MM resection was necessary in 22.7% of cases. Overall survival (OS) and progression-free survival (PFS) did not significantly differ between TOS and CS groups. Radiological depth of invasion (rDOI) < 10 mm is correlated with MM preservation in 89% of cases, while rDOI > 10 mm is correlated with MM resection only in 23.8% of cases. Pathological depth of invasion (pDOI) discrepancies were observed in the two groups: in CS group is shown a higher pDOI (> 10 mm) confirmation (90%). Surgical complications and functional outcomes differed between TOS and CS groups.

CONCLUSION

Considering MM invasion for surgical approach selection in cT2-cT3 FOM tumors appears oncologically safe, with better functional outcomes in muscle preservation. Preoperative MRI for MM assessment combined with intraoperative FS analysis provides reliable guidance for surgical decision-making.

Role of Computed Tomography in Prediction of Depth of Invasion and Cervical Lymph Node Metastasis in Oral Cancer

Objectives

The primary aim is to determine the accuracy of contrast-enhanced computed tomography (CT) in evaluation of depth of invasion (DOI) and detection of cervical node metastasis. We also analysed the relation between radiographic DOI (rDOI) and cervical lymph node metastasis.

Materials and Methods

We have retrospectively reviewed 201 oral squamous cell carcinoma (SCC) patients. The rDOI was compared with histological DOI. Sensitivity, specificity, accuracy, and negative (NPV) and positive (PPV) predictive values were evaluated for CT scan in predicting nodal metastasis. The relation between rDOI and lymph node metastasis was analysed using ROC curve.

Results

rDOI correlated significantly with histologic DOI for oral tongue, buccal mucosa, gingiva, and mucosal lip SCC (P < 0.05) and for tumours with rDOI > 5 mm. The sensitivity, specificity, PPV, NPV and accuracy rate of CT scan were found to be 84.71%, 50.86%, 55.81%, 81.94% and 65.17%, respectively. Tumours with rDOI > 16 mm had significant (P < 0.001) chance of having neck node metastasis.

Conclusion

CT-derived DOI correlates significantly with pathological DOI although both are not similar. CT scan can predict nodal metastasis in fairly accurate manner using the four radiographic criteria used in this study. Radiographic depth of invasion can be used as predictor of cervical node metastasis.

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.

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.

Global research trends in tongue cancer from 2000 to 2022: bibliometric and visualized analysis

OBJECTIVES

This study conducts a systematic bibliometric analysis of tongue cancer publications to identify key topics, hotspots, and research distribution.

METHODS

We analyzed tongue cancer publications in the Web of Science core collection database, assessing their quantity and quality. We investigated contributors, including countries, affiliations, journals, authors, and categories, within collaborative networks. Additionally, we synthesized key research findings using various analytical techniques, such as alluvial flow, burstness analysis, cluster analysis, co-occurrence network of associations, and network layer overlay.

RESULTS

From 2000 to 2022, this bibliometric study covers 2205 articles and reviews across 617 journals, involving 72 countries, 2233 institutions, and 11,266 authors. It shows consistent growth, particularly in 2016. Key contributors include China (499 publications), Karolinska Institute (84 publications), Oral Oncology (144 publications), and Tuula Salo (47 publications). Other notable contributors are the USA (16,747 citations), the National Cancer Institute (NCI) (2597 citations), and the Memorial Sloan-Kettering Cancer Center (MSK) (2231 citations). Additionally, there are significant teams led by Tuula Salo and Dalianis. We have identified six primary clusters: #0 apoptosis, #1 depth of invasion, #2 radiotherapy, #3 hpv, #4 tongue cancer, #5 oral cancer. The top ten highly cited documents primarily pertain to epidemiology, prognostic indicators in early-stage oral tongue cancer, and HPV. Additionally, we observed 16 reference clusters, with depth of invasion (#3), young patients (#4), and tumor budding (#6) gaining prominence since 2012, indicating sustained research interests.

CONCLUSIONS

This analysis emphasizes the increasing scholarly interest in tongue cancer research. The bibliometric evaluation highlights pivotal recent research themes such as HPV, depth of invasion, tumor budding, and surgical margins.

CLINICAL RELEVANCE

The bibliometric analysis highlights the key topics and studies which have shaped the understanding and management of tongue cancer.

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.

Accuracy of magnetic resonance imaging in the assessment of depth of invasion in tongue carcinoma: A systematic review and meta-analysis

Tongue carcinoma constitutes 10.4-46.9% of all oral squamous cell carcinomas (OSCCs) and is notoriously known for invading tissues deeper than the evident gross margins. The deeper the tumor invades, the higher are its chances of future morbidity and mortality due to extensive neck dissection and risk of recurrence. Magnetic resonance imaging (MRI) is a noninvasive diagnostic aid used for measuring a preoperative tumor's depth of invasion (DOI) as it can efficiently outline soft tissue tumors from adjacent normal tissue. To assess various MRI modalities used in measuring DOI in tongue carcinoma and their reliability compared with other DOI measuring modalities. The protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42022330866), and the following Preferred Reporting Items for a Systematic Review and Meta-Analysis (PRISMA) Diagnostic Test Accuracy guidelines were performed. PubMed electronic database was searched using a combination of keywords for relevant articles in the English language since 2016. Critical appraisal was carried out using the Quality Assessment of Diagnostic Accuracy Studies-Comparative (QUADAS-C) risk-of-bias (RoB) assessment tool. A weighted mean difference (WMD) was calculated between MRI and histopathological DOI along with pooled correlation and subgroup analysis, where possible. A total of 795 records were retrieved of which 17 were included in the final review with 13 included for meta-analysis. A high RoB was found for most studies for all parameters except flow and timing. WMD showed a statistically significant MRI overestimation of 1.90 mm compared with histopathology. Subgroup analysis showed the 1.5 Tesla machine to be superior to the 3.0 Tesla machine, while imaging sequence subgroup analysis could not be performed. MRI is a viable preoperative DOI measurement modality that can help in efficient treatment planning to decrease surgical morbidity and mortality.

Accuracy of Magnetic Resonance Imaging in Detecting Tumor Depth of Invasion in Squamous Cell Carcinoma of the Tongue: A Systematic Review

Objective

The objective of the study was to detect the accuracy of Magnetic Resonance Imaging (MRI) in assessing tumor depth of invasion (DOI) in squamous cell carcinoma (SCC) of the tongue.

Material and Methods

The electronic search of PubMed (including MEDLINE), COCHRANE CENTRAL and Google Scholar search engine for articles published from January 1, 2000, to September 31, 2021, was conducted and also searched the lists of references of relevant articles and reviews for studies involving patients with squamous cell carcinoma of the tongue.

Results

A total of 5362 articles were retrieved in the initial search. After the initial search process, 13 full-text articles were reviewed. Out of these 13 articles, seven met the inclusion criteria and were thus included in this systematic review.

Conclusion

The MRI-determined DOI based on T1-weighted sequences increases with increasing T stage. There is the highest correlation between the MRI-derived DOI and the histopathological DOI with increasing T stage. Therefore, MRI provides satisfactory diagnostic accuracy for measuring tumor DOI and, thus, may be considered a predictor of tumor stage.

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.

Imaging Recommendations for Diagnosis, Staging, and Management of Oral Cancer

Oral cavity cancers contribute to a majority of cancers in India. Clinical examination alone cannot determine the deeper extent of the disease; therefore, need for cross-sectional imaging including computed tomography and magnetic resonance imaging becomes indispensable for pre-treatment evaluation to decide optimal plan of management. Oral cavity squamous cell cancers (OSCC) can be treated with surgery alone, whereas deep muscle, neurovascular, osseous, or nodal involvement on imaging suggests advanced disease that requires a combination of surgery, radiation, and/or chemotherapy. Because of the complex anatomy of the oral cavity and its surrounding structures, imaging is crucial for locoregional staging and early detection of distant metastases. Imaging plays indispensable role not only in diagnosis but also in planning the management. An optimal guideline paper for developing countries like India is lacking that not only helps standardize the management but will also assist oncologists make reasonable decisions and reduce the unnecessary imaging. This imaging guideline paper will discuss the optimal imaging in diagnosis and management OSCC for Indian subcontinent.

Preoperative MRI for oral tongue squamous cell carcinoma: timing and correlation to histopathology

Magnetic resonance imaging (MRI) is an integral part of the evaluation of local and regional disease in tongue squamous cell carcinoma prior to surgery. The aim of this study was to evaluate the accuracy of MRI in assessing tumour dimensions, as well as the impact of the time-lag from diagnostic biopsy on the accuracy of MRI. The medical records of 64 patients with tongue carcinoma were reviewed retrospectively. Tumour maximum diameter and tumour depth of invasion were compared between pathology and MRI (T1- and T2-weighted). MRI-derived maximum tumour diameter and depth of invasion correlated strongly with histopathology: T1-weighted (r = 0.700 and r = 0.813, respectively) and T2-weighted (r = 0.734 and r = 0.834, respectively). A significant correlation was found between measurements on T1 and T2 MRI for both parameters (P = 0.955 and P = 0.984, respectively). The accuracy rate of MRI for T-staging of early tumours was low: 10% for T1 tumours; 39.3% for T2 tumours. A time-lag of less than 2 weeks between the diagnostic biopsy and MRI adversely affected the correlation of tumour dimensions. MRI is a reliable tool for evaluating tongue carcinoma; however, it overestimates early tumours. A 2-week delay after diagnostic biopsy is desired before completing an MRI. Alternatively, if logistics allow, a pre-biopsy MRI is preferred, especially for T1-T2 tumours.

Prediction Formula for Pathological Depth of Invasion From Clinical Depth of Invasion in Tongue Squamous Cell Carcinoma (SCC) Stage I/II Cases

BACKGROUND

 The depth of invasion (DOI) of tongue squamous cell carcinoma (SCC) is an important prognostic factor. The definition is clear for pathological DOI (pDOI), but the treatment strategy is determined by the preoperative clinical DOI (cDOI). Few studies have investigated the difference between these DOIs. The purpose of this study was to obtain the correlation equation between cDOI and pDOI for Stage I/II tongue SCC and to consider the points to be noted in actual clinical practice.

METHODS

 In this retrospective study, 58 patients with clinical stage I/II tongue SCC were included. Correlations between cDOI and pDOI were obtained for all 58 cases, as well as for 39 cases which excluded superficial and exophytic lesions.

RESULTS

 The overall cDOI and pDOI median values were 8.0 and 5.5 mm, respectively; the 2.5 mm reduction was significant (p < 0.01). The correlation equation was pDOI = 0.81 × cDOI-0.23 (r = 0.73). Furthermore, re-analysis of the 39 cases revealed that pDOI = 0.84 × cDOI-0.37 (r = 0.62). Hence, a derived equation pDOI = 0.84 × (cDOI-0.44) was obtained to predict pDOI from cDOI.

CONCLUSIONS

 This study indicated that it is necessary to consider contraction due to specimen fixation by subtracting the thickness of the mucosal epithelium. Clinical T1 cases with a cDOI of 5 mm or less had a pDOI of 4 mm or less, and it would be expected to have low positive rate of neck lymph node metastasis.

Correlation between radiologic depth of invasion and pathologic depth of invasion in oral cavity squamous cell carcinoma: A systematic review and meta-analysis

OBJECTIVES

To comprehensively assess the correlation between radiologic depth of invasion (rDOI) and pathologic depth of invasion (pDOI) in oral cavity squamous cell carcinoma (OSCC) by meta-analysis.

MATERIALS AND METHODS

PubMed and Embase databases were searched to find pertinent articles reporting rDOI of OSCC. Studies evaluating the correlations and mean differences (MDs) between rDOI and pDOI were included. The rDOI was measured based on ultrasound (US), computed tomography (CT), or magnetic resonance imaging (MRI). The correlation coefficients and MDs between rDOI and pDOI were meta-analytically pooled. Between-study heterogeneity was assessed using Higgins' inconsistency index (I²). Subgroup analysis was performed based on imaging modality.

RESULTS

Twenty-three studies with 1787 patients were included. The pooled correlation coefficient and MD were 0.86 (95 % confidence interval [CI], 0.82-0.90; I² = 66.9 %) and 1.84 mm (95 % CI, 1.02-2.65 mm; I² = 88.2 %), respectively. In subgroup analysis, MRI showed the largest MD (n = 12, 2.61 mm), followed by US (n = 2, -0.41 mm) and CT (n = 2, 0.12 mm). US showed the highest correlation coefficient (n = 3, 0.91), followed by MRI (n = 12, 0.85) and CT (n = 3, 0.82).

CONCLUSION

rDOI measured by US, CT, and MRI demonstrated excellent correlations with pDOI.

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

The inclusion of depth of invasion (DOI) in the American Joint Committee on Cancer's staging system for oral cavity squamous cell carcinoma (SCC) has major clinical impacts. Recent studies have evaluated the reliability of imaging modalities and biopsy techniques to measure DOI preoperatively. The objective of this systematic review and meta-analysis was to comprehensively include all previously described methods to measure preoperative DOI in oral tongue SCC (OTSCC) and to compare their reliability. A systematic review was conducted on PubMed, Embase and Cochrane according to the PRISMA guidelines. Studies that evaluated the reliability of DOI measured on biopsy or imaging (rDOI) by comparing it to DOI on histopathology (pDOI) were included for extraction. A meta-analysis was conducted to obtain pooled correlation coefficients for each imaging modality. The pooled correlation coefficients between rDOI and pDOI were 0.86 (CI_95% = [0.82-0.88]) and 0.80 (CI_95% = [0.70-0.87]) for magnetic resonance imaging (MRI) studies and computed tomography (CT) studies, respectively. For ultrasound (US), the correlation coefficient could only be measured by including studies which measured not only DOI but also tumor thickness. It was 0.89 (CI_95%= [0.82-0.94]). Overall, MRI is the better studied modality. It has a good reliability to measure preoperative rDOI in OTSCC. CT is less studied but appears to be less reliable. US cannot be compared to these imaging modality as it has been used more often to measure TT than DOI.

A Prognostic Model Generated from an Apparent Diffusion Coefficient Ratio Reliably Predicts the Outcomes of Oral Tongue Squamous Cell Carcinoma

This study aimed to develop an apparent diffusion coefficient (ADC) ratio-based prognostic model to predict the recurrence and disease-free survival (DFS) of oral tongue squamous cell carcinoma (OTSCC). A total of 188 patients with cT1-2 oral tongue squamous cell carcinoma were enrolled retrospectively. Clinical and laboratory data were extracted from medical records. The ADC values were measured at the regions of interest of the tumor and non-tumor tissues of the MRI images, and the ADC ratio was used for comparison between the patient with recurrence (n = 83 case, 44%) and patients without recurrence (n = 105 cases, 56%). Cox proportional hazards models were generated to analyze the risk factors of cancer recurrence. A nomogram was developed based on significant risk factors to predict 1-, 5- and 10-year DFS. The receiver operator characteristic (ROC) curves of predictors in the multivariable Cox proportional hazards prognostic model were generated to predict the recurrence and DFS. The integrated areas under the ROC curve were calculated to evaluate discrimination of the models. The ADC ratio, tumor thickness and lymph node ratio were reliable predictors in the final prognostic model. The final model had a 71.1% sensitivity and an 81.0% specificity. ADC ratio was the strongest predictor of cancer recurrence in prognostic performance. Discrimination and calibration statistics were satisfactory with C-index above 0.7 for both model development and internal validation. The calibration curve showed that the 5- and 10-year DFS predicted by the nomogram agreed with actual observations.

Ultrasound accurately assesses depth of invasion in T1‐T2 oral tongue cancer

Background

Depth of invasion (DOI) is important for the T‐classification of squamous cell carcinoma of the oral tongue (SCCOT) and incorporated in the TNM 8 classification of oral cavity cancer. To determine DOI clinical palpation is performed, but the preferred radiological modality remains controversial. The aim of this study was to investigate the assessment of DOI using ultrasound (US‐DOI).

Methods

The DOI was assessed in 40 patients with T1–T3 SCCOT by ultrasound, palpation, computed tomography and magnetic resonance imaging (MRI). Histopathological DOI (H‐DOI) was gold standard. Bland–Altman analysis was used to compare mean difference and 95% limits of agreement (LOA).

Results

The mean difference of US‐DOI was −0.5 mm (95% LOA −4.9–4.0) compared to H‐DOI and the mean difference for MRI was 3.9 mm (95% LOA −2.3–10.2). In the subgroup analysis of cT1‐T2 the US‐DOI mean difference was 0.1 mm and the 95% LOA limits −2.5–2.7.

Conclusions

Ultrasound seems to be the most accurate method to assess DOI in T1‐T2 SCCOT. MRI overestimates DOI and cannot assess a substantial proportion of the tumors.

Level of Evidence

2c.

MR imaging of Oral Cavity and Oropharyngeal Cancer

MR imaging is the modality of choice in the evaluation of oral cavity and oropharyngeal cancer. Routine postcontrast MR imaging is important for the accurate localization and characterization of the locoregional extension of oral cavity and oropharyngeal cancers. The anatomy of the oral cavity and oropharynx is complex; accurate interpretation is vital for description of the extension of the masses. Understanding the new changes in the eighth edition of the American Joint Committee on Cancer staging system. MR imaging is the imaging modality of choice for detection of perineural spread.

RF Coil Setup for 31P MRSI in Tongue Cancer in vivo at 7 T

Surgery for tongue cancer often results in a major loss in quality of life. While MRI may be used to minimise the volume of excised tissue, often the full tumour extent is missed. This tumour extent may be detected with metabolic imaging. One of the main reasons for the lack of metabolic information on tongue cancer would be the absence of an x-nuclear coil with the tongue as a focus target. Metabolic MRI through ³¹P MRSI is known as a powerful tool to non-invasively study elevated cell proliferation and disturbed energy metabolism in tumours. Severe magnetic field non-uniformities are inherently caused by the substantial difference in magnetic susceptibilities of tissue and air in the mouth and its environs. Despite this, the wide chemical shift dispersion of ³¹P could still facilitate precise detection of the cell proliferation biomarkers, phospomonoesters and diesters, as well as energy metabolites ATP, inorganic phosphate, and phosphocreatine potentially mapped over the tongue or tumour in vivo. In this study, we present the first ³¹P MRSI data of the human tongue in vivo from healthy volunteers and a patient with a tongue tumour at 7 T MRI using a ¹H 8-channel transceiver setup placed inside a body ³¹P transmitter, which is able to get a uniform excitation from the tongue while providing comfortable access to the patient. In addition, a user-friendly external ³¹P receiver array is used to provide high sensitivity (80%) comparable to an uncomfortable inner mouth loop coil positioned on the tongue. The primary aim is the demonstration of ³¹P metabolite profiles in the tongue and the differences between healthy and malignant tissue. Indeed, clear elevated cell proliferation expressed as enhanced phosphomonoesters is observed in the tumour vs. the healthy part of the tongue. This can be performed within a total scan duration of 30 min, comparable to clinical scans, with a spatial resolution of 1.5 cm for the 10-min ³¹P MRSI scan.

Subtraction iodine imaging with area detector CT to improve tumor delineation and measurability of tumor size and depth of invasion in tongue squamous cell carcinoma

Purpose

Tumor size and depth of invasion (DOI) are mandatory assessments for tumor classification in tongue cancer but are often non-assessable on CT due to dental artifacts. This study investigated whether subtraction iodine imaging (SII) would improve tumor delineation and measurability.

Materials and methods

Fifty-seven consecutive patients with tongue cancer, who underwent scanning with a 320-row area detector CT with contrast administration and were treated with surgical resection, were retrospectively evaluated. CT was reconstructed with single-energy projection-based metallic artifact reduction (sCT). SII was generated by subtracting the pre-contrast volume scans from the post-contrast volume scans using a high-resolution deformable registration algorithm. MRI scans were also evaluated for comparing the ability of measurements. Two radiologists visually graded the tumor delineation using a 5-point scale. Tumor size and DOI were measured wherever possible. The tumor delineation score was compared using the Wilcoxon signed-rank method. Spearman’s correlations between imaging and pathological measurements were calculated. Intraclass correlation coefficients of measurements between readers were estimated.

Results

The tumor delineation score was greater on sCT-plus-SII than on sCT alone (medians: 3 and 1, respectively; p < 0.001), with higher number of detectable cases observed with sCT-plus-SII (36/57 [63.2%]) than sCT alone (21/57 [36.8%]). Tumor size and DOI measurability were higher with sCT-plus-SII (29/57 [50.9%]) than with sCT alone (17/57 [29.8%]). MRI had the highest detectability (52/57 [91.2%]) and measurability (46/57 [80.7%]). Correlation coefficients between radiological and pathological tumor size and DOI were similar for sCT (0.83–0.88), sCT-plus-SII (0.78–0.84), and MRI (0.78–0.90). Intraclass correlation coefficients were higher than 0.95 for each modality.

Conclusions

SII improves detectability and measurability of tumor size and DOI in patients with oral tongue squamous cell carcinoma, thus increasing the diagnostic potential. SII may also be beneficial for cases unevaluable on MRI due to artifacts or for patients with contraindications to MRI.

Assessment of tumor depth in oral tongue squamous cell carcinoma with multiparametric MRI: correlation with pathology

OBJECTIVES

To compare the correlation of depth of invasion (DOI) measured on multiple magnetic resonance imaging (MRI) sequences and pathological DOI, in order to determine the optimal MRI sequence for measurement.

METHODS

A total of 122 oral tongue squamous cell carcinoma (OTSCC) patients were retrospectively analyzed, who had received preoperative MRI and surgical resection. DOIs measured on fat-suppressed T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), dynamic enhanced-T1 high-resolution insotropic volume examination (e-THRIVE), and contrast-enhanced fat-suppressed T1WI (CE-T1WI) were respectively compared to those measured in pathologic specimens. The cutoff value of the best correlated MRI sequence was determined, and the T staging accuracy of MRI-derived DOI was evaluated.

RESULTS

DOI derived from e-THRIVE showed the best correlation (r = 0.936, p < 0.001) with pathological DOI. The area under the curve values of MRI-derived DOI distinguishing T1 stage from T2 stage and distinguishing T2 stage from T3 stage were 0.969 and 0.974, respectively. The T staging criteria of MRI-derived DOI were 6.2 mm and 11.4 mm, with a staging accuracy of 86.9% compared to pathological DOI criteria of 5 mm and 10 mm.

CONCLUSION

E-THRIVE was the optimal MR sequence to measure the MR-derived DOI, and DOI derived from e-THRIVE could serve as a potential cut-off value as a clinical T staging indicator of OTSCC.

KEY POINTS

• Multiparametric MRI helps radiologists to assess the neoplasm invasion in patients with oral tongue squamous cell carcinoma. • Retrospective study indicated that measurement was most accurate on enhanced-T1 high-resolution insotropic volume examination dynamic contrast enhancement images. • T staging of oral tongue squamous cell carcinoma was accurate according to the dynamic contrast enhancement MRI-derived depth of invasion.

Assessment of squamous cell carcinoma of the floor of the mouth with magnetic resonance imaging

PURPOSE

We aimed to use magnetic resonance imaging (MRI) to determine the relationship between the pathological depth of invasion (DOI), undetectability, and tumor thickness of squamous cell carcinoma of the floor of the mouth.

MATERIALS AND METHODS

We retrospectively evaluated the relationship between pathological DOI and MRI detectability, as well as the relationship between pathological DOI and tumor thickness on coronal fat-suppressed contrast-enhanced T1-weighted imaging or coronal T2-weighted imaging.

RESULTS

We analyzed 30 patients with squamous cell carcinoma of the floor of the mouth; MRI revealed that the pathological DOI of the 11 undetectable lesions (median 2 mm) was smaller than that of the 19 detectable lesions (median 14 mm) (p < 0.001), and the cut-off value was 3 mm (sensitivity, 0.84; specificity, 0.91; area under the curve, 0.89). Tumor thickness on coronal fat-suppressed contrast-enhanced T1-weighted imaging was assessed in all 19 detectable lesions; however, tumor thickness on coronal T2-weighted imaging could not be assessed in eight cases. Tumor thickness on coronal fat-suppressed contrast-enhanced T1-weighted imaging was found to be significantly associated with the pathological DOI.

CONCLUSIONS

Undetectability on MRI indicates superficial lesions with a pathological DOI value that is less than 3 mm. In detectable lesions, tumor thickness on coronal fat-suppressed contrast-enhanced T1-weighted imaging is associated with pathological DOI.

Diagnostic accuracy of magnetic resonance imaging in detecting depth of invasion of tongue cancers

The recent eighth edition of the American Joint Committee on Cancer (AJCC) staging system has introduced depth of invasion (DOI) as one of its important components. DOI is also important for deciding neck management in superficial tongue cancers. Magnetic resonance imaging (MRI) is mainly used to assess DOI, and in this study we have evaluated the efficacy of MRI to detect it. This is a retrospective study consisting of 60 treatment-naïve tongue cancer patients operated on between July 2017 and June 2019. Patients underwent MR imaging on an Optima MR450W 1.5T unit, and MRI was reported by two experienced ead and eck adiologistss. Postoperative histological DOI was considered the gold standard. The correlation coefficient was derived for postoperative DOI and MRI-detected DOI. A subgroup analysis of superficial tongue cancer was also done. The mean MRI DOI was 13.7 mm and the mean histological DOI 12.45 mm. The shrinkage factor was 0.6 mm. Pearson's correlation coefficient was 0.80 (p=<0.001) for Radiologist 1 and 0.85 (p=<0.001) for Radiologist 2. The interobserver variation was low, with a correlation coefficient between the two radiologists of 0.965 (p=<0.001). For superficial tongue cancers there was moderate correlation for MRI and histologically-detected DOI with a kappa value of 0.681 (p=0.03). As per the ROC curve, the cut-off value for MRI DOI to predict nodal metastasis was 4.6 mm. MRI has high reliability to predict the DOI of tongue cancers. The interobserver variation was low. The diagnostic accuracy in cases of superficial tongue cancer was moderate.

Importance and implications of neurovascular bundle involvement and other MRI findings of oral tongue squamous cell carcinoma (OTSCC) on prognosis

BACKGROUND

The description for T4a oral tongue cancer in the 8th edition AJCC staging can be improved further. In this article we attempted to identify the important radiological (MRI) findings that could possibly be included in the staging eventually.

METHODS

We included all oral tongue squamous cell carcinoma patients who underwent surgery at TMH between Jan 2012 to Dec 2018 and whose MRIs were available for review. The relation of the tumor to the neurovascular bundle (NVB) on MRI was classified as Type I to IV. The association of the type of NVB involvement with DFS and the presence of PNI in the final HPR was analyzed.

RESULTS

Two-hundred and fifty-nine patients satisfied the eligibility criteria. The majority of them were men (82.6%), with a median age of 49 Yrs. Sixty-nine percent of patients had either abutment (Type III) or encasement (Type IV) of the NVB. The presence of Abutment/encasement of the NVB was significantly associated with the presence of PNI in the final HPR (p < 0.001). This abutment/encasement was seen in clinically advanced T-stage tumors. However, the presence of abutment/encasement of the NVB influenced the DFS in the univariate analysis only.

CONCLUSION

Abutment/encasement of the NVB in patients with carcinoma oral tongue is often seen in advanced-stage tumors and is significantly associated with the presence of PNI in the final HPR. Hence, the relation of the tumor with the NVB should be further assessed to understand its importance and its possible inclusion in the AJCC T-staging.

Prognostic value of MRI-measured tumor thickness in patients with tongue squamous cell carcinoma

This study aimed to assess the prognostic value of MRI-measured tumor thickness (MRI-TT) in patients with tongue squamous cell carcinoma (SCC). This single-center retrospective cohort study included 133 pathologically confirmed tongue SCC patients between January 2009 and October 2019. MRI measurements of tongue SCC were based on axial and coronal T2-weighted (T2WI) and contrast-enhanced T1-weighted (CE-T1WI) images. Two radiologists independently measured MRI-TT. Intraclass correlation coefficients (ICC) were calculated for inter-rater agreements. Spearman's rank correlation between MRI-TT and pathologic depth of invasion (pDOI) was assessed. Cox proportional hazards analyses on recurrence-free (RFS) and overall survival (OS) were performed for MRI-TT and pDOI. Kaplan-Meier survival curves were plotted with log-rank tests. The intra- and inter-rater agreements of MRI-TT were excellent (ICC: 0.829-0.897, all P < 0.001). The correlation between MRI-TT and pDOI was good (Spearman's correlation coefficients: 0.72-0.76, P < 0.001). MRI-TT were significantly greater than pDOI in all axial and coronal T2WI and CE-T1WI (P < 0.001). In multivariate Cox proportional hazards analysis, MRI-TT measured on axial CE-T1WI yielded a significant prognostic value for OS (hazards ratio 2.77; P = 0.034). MRI-TT demonstrated excellent intra- and inter-rater agreements as well as high correlation with pDOI. MRI-TT may serve as a prognostic predictor in patients with tongue SCC.

A comparative study between CT, MRI, and intraoral US for the evaluation of the depth of invasion in early stage (T1/T2) tongue squamous cell carcinoma

Objectives

This study aimed to clarify the accuracy of intraoral ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) in preoperative image depth of invasion (DOI) measurement of T1/T2 tongue cancer through comparison with histopathological measurements.

Methods

Imaging of the primary lesions was performed at our hospital; the lesions were classified into T1 and T2 based on the 8th edition of the AJCC/UICC, and surgery performed. There was histopathological confirmation of lesions as squamous cell carcinoma in 48 patients with tongue cancer. T3 and T4 cases, cases in which preoperative chemotherapy and radiation therapy were performed, and cases where biopsy was performed before imaging were excluded. The radiological DOI in US, CT, and MRI and the histopathological DOI as base were comparatively investigated and statistical analyses were performed by Bland–Altman analysis and Spearman's rank correlation coefficient.

Results

Bland–Altman analysis showed that the US radiological DOI was overestimated by an average of 0.2 mm compared to the histopathological DOI, while CT and MRI radiological DOI were overestimated by an average of 2–3 mm. The comparison of CT and MRI revealed that the difference between the MRI and histopathological DOI, as well as the 95% limit of agreement, were smaller than those of the CT radiological DOI.

Conclusions

US is the most accurate preoperative diagnostic tool for T1 and T2 squamous cell carcinoma; CT and MRI tend to have an overestimation of about 2–3 mm and so caution is required.

Development and validation of multiparametric MRI-based nomogram for predicting occult metastasis risk in early tongue squamous cell carcinoma

Background

Nomograms are currently used in predicting individualized outcomes in clinical oncology of several cancers. However, nomograms for evaluating occult nodal metastasis of patients with squamous cell carcinoma of lateral tongue (SCCLT) have not been widely investigated for their functionality. This retrospective cohort study was designed to address this question.

Methods

This study was divided into primary and validation cohorts. The primary cohort comprised 120 patients diagnosed between 2012 and 2017, whereas the validation cohort included 41 patients diagnosed thereafter. The diagnostic value of multiparametric MRI, including radiologic tumor thickness threshold (rTTT) in three-dimensions, paralingual distance, and sublingual distance were investigated. A nomogram was developed based on stepwise logistic regression of potential predictors associated with nodal metastasis in the primary cohort and then tested for predictive accuracy in the validation cohort using area under the curve (AUC) and goodness-of-fit tests.

Results

Multivariate analysis, tumor size (odd ratio [OR] 15.175, 95% confidence interval [CI] 1.436–160.329, P = 0.024), rTTT (OR 11.528, 95% CI 2.483–53.530, P = 0.002), paralingual distance (OR 11.976, 95% CI 1.981–72.413, P = 0.005), and tumor location (OR 6.311, 95% CI 1.514–26.304, P = 0.011) were included in the nomogram to predict the likelihood of having cervical metastasis. A nomogram cutoff value of 210 points (sensitivity 93.8%, specificity 87.5%) was significantly different to classify the patients metastasis risk group (P < 0.001). Nomogram showed predictive accuracy with AUC 0.881 (95% CI 0.779–0.983, P < 0.001) and good calibration after the validation.

Conclusions

A preoperative nomogram incorporating multiparametric MRI demonstrated good prediction and performed adequately in our study. Three-dimensional assessment of occult metastasis risk value obtained from this nomogram can assist in preoperative decision making for individual patients with early-stage SCCLT. The probability of nodal metastasis tended to be greater than 20% in patients with high metastasis risk or nomogram total score > 210 points.

Can MRI-derived depth of invasion predict nodal recurrence in oral tongue cancer?

OBJECTIVES

To evaluate the prognostic value of preoperative radiological findings for nodal recurrence in clinically node-negative (cN0) patients with oral tongue squamous cell carcinoma (SCC).

METHODS

The study population consisted of 52 patients with cT1-2N0 oral tongue SCC classified according to the 7th edition of the Union for International Cancer Control (UICC) staging system. The subjects had undergone preoperative radiological examinations, including magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography. All patients were treated with local resection and watchful waiting for neck management. Using an unpaired t test, Pearson's chi-squared test, and the Kaplan-Meier method, the MRI-derived depth of invasion (DOI), the standardized uptake value (SUV) on FDG-PET, and the T stage according to the 7th and 8th UICC were assessed as prognostic factors.

RESULTS

The MRI-derived DOI was recorded as ≤ 5 mm in 24 patients and > 5 mm in 28 patients. During the follow-up period, nine patients exhibited nodal recurrence, with the MRI-derived DOI being significantly higher in patients with positive than in those with negative (p = 0.011). The SUV was not significant. Five-year cumulative nodal recurrence probabilities were 4.5% for patients with an MRI-derived DOI ≤ 5 mm, while it was 32.1% for > 5 mm (p = 0.013). Although the T classifications were not significant, none of our patients whose T stage according to the 8th UICC was T1 suffered nodal recurrence.

CONCLUSIONS

MRI-derived DOI can predict nodal recurrence, while preoperative information may assist in treatment planning for oral tongue SCC.

Correlation between the magnetic resonance imaging features of squamous cell carcinoma of the buccal mucosa and pathologic depth of invasion

OBJECTIVE

The objective of this study was to determine correlations between magnetic resonance imaging (MRI) features including radiologic depth of invasion (r-DOI) and pathologic DOI (p-DOI) of squamous cell carcinoma of the buccal mucosa.

STUDY DESIGN

In total, 31 lesions were retrospectively evaluated. MRI findings included detectability, buccinator muscle invasion (positive: BMI+, negative: BMI-), buccal fat pad invasion (positive: BFPI+, negative: BFPI-), and r-DOI measured on T2-weighted images (T2-DOI) and contrast-enhanced T1-weighted images (CET1-DOI). These findings were compared to the p-DOI of the tumors.

RESULTS

The p-DOI values of undetectable lesions were smaller than those of detectable lesions (P < .001), and the cutoff value was 1 mm. BMI+ and BFPI+ lesions had significantly larger p-DOI values than the corresponding BMI- and BFPI- lesions (P < .001), with cutoff values of 5 and 6 mm, respectively. The correlation coefficient between CET1-DOI and p-DOI was 0.68 (P < .001). CET1-DOI values were larger than p-DOI (P < .001) and the average difference between them was 3.4 mm. T2-DOI was inconclusive in 50% of cases. Interobserver agreements of MRI evaluation were good to very good.

CONCLUSION

MRI-derived parameters were useful in estimating p-DOI and may be helpful in predicting the depth of invasion of tumors and the risk of lymph node metastasis.

Biopsy quality is essential for preoperative prognostication in oral tongue cancer

A role for incisional biopsy in preoperative prognostication is increasingly being advocated in oral tongue squamous cell carcinomas (OTSCC). Biopsies at two locations were compared, and prognostic factors in biopsies and their corresponding resections were evaluated. A total of 138 OTSCC biopsy slides from Finland and Saudi Arabia were compared for size (horizontal and vertical) and invasive front. The Finnish cases were assessed for tumor stroma ratio (TSR) and tumor-infiltrating lymphocytes (TILs) using light microscopy and digital image analysis assessment and compared. Furthermore, TSR, TILs, and previously analyzed budding and depth of invasion (BD) score in biopsies were compared with their evaluation in the corresponding resections. Fifty-nine percent of Finnish and 42% of Saudi Arabian biopsies were ≥ 5 mm deep, while 98% of Saudi Arabian and 76% of Finnish biopsies were ≥ 5 mm wide. Assessment of invasion front was possible in 72% of Finnish in comparison with 40% of Saudi Arabian biopsies. There was 86.8% agreement between TSR and 75% agreement between TIL evaluation using light microscopy and digital assessment. Significant agreement was obtained on comparing the TSR (p = 0.04) and BD (p < 0.001) values in biopsies and resections. Biopsies of ≥ 5 mm depth from representative OTSCC areas are essential for prognostic information. Clinical pathologists are advised to assess BD score and TSR for prognostic features in such biopsies.

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

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.

Electronic supplementary material

The online version of this article (10.1007/s00405-020-06421-w) contains supplementary material, which is available to authorized users.

Comparison of diagnostic accuracy between [18F]FDG PET/MRI and contrast-enhanced MRI in T staging for oral tongue cancer

OBJECTIVE

Integrated PET/MRI with [¹⁸F]FDG is advantageous in that it enables simultaneous PET and MR imaging with higher soft-tissue contrast, multiplanar image acquisition, and functional imaging capability without using fat suppression and gadolinium-based contrast agents (GBCAs). The aims of this study were to demonstrate the feasibility of [¹⁸F]FDG PET/MRI for assessing the extent of the primary tumor (T) in oral tongue cancer (OTC) based on the 8th edition of American Joint Committee on Cancer (AJCC) cancer staging system, and to compare the diagnostic accuracy between [¹⁸F]FDG PET/MRI and contrast-enhanced MRI (ceMRI).

METHODS

18 patients with biopsy-proven operable OTC underwent preoperative regional [¹⁸F]FDG PET/MRI and ceMRI within 2 weeks. For [¹⁸F]FDG PET/MRI, rainbow-colored PET images were overlaid on the corresponding MR images. Tumor size and the depth of invasion (DOI) were visually measured on [¹⁸F]FDG PET/MRI and ceMRI. The size, DOI, and clinical T stage were evaluated using the final surgical pathology as the reference.

RESULTS

Of the 18 OTCs, one was not detected by ceMRI due to metal artifacts from an artificial denture, and another due to superficial type (pathological DOI = 0 mm). Tumor sizes measured by ceMRI and [¹⁸F]FDG PET/MRI had significant positive correlations with the pathological size (r = 0.80 and r = 0.90, respectively), and DOIs measured by ceMRI and [¹⁸F]FDG PET/MRI had significant positive correlations with the pathological DOI (r = 0.74 and r = 0.64, respectively). The means ± SD of size (mm) were 20.4 ± 9.1, 22.9 ± 10.9, and 26.2 ± 10.0, and those of DOI (mm) were 7.1 ± 2.5, 6.9 ± 2.2, and 5.8 ± 3.2 for ceMRI, [¹⁸F]FDG PET/MRI, and pathology, respectively. A significant difference was observed in tumor size between ceMRI and pathology (p < 0.05), whereas no significant differences were observed between any other sizes, DOIs, or T stages. The accuracy for T status was 72% (13/18 including 2 undetectable cases) for ceMRI and 89% (16/18) for [¹⁸F]FDG PET/MRI.

CONCLUSIONS

Although shallow DOIs are often overestimated, regional [¹⁸F]FDG PET/MRI without fat suppression and gadolinium enhancement is comparable to and may be substituted for ceMRI in preoperative T staging for OTC patients, reducing metal artifacts and avoiding the adverse effects of GBCAs.

Assessing the magnetic resonance imaging in determining the depth of invasion of tongue cancer

OBJECTIVES

To assess the magnetic resonance imaging (MRI) in predicting tumour's depth of invasion (DOI) of tongue cancer by comparing to pathology and to determine the cut-off value of MRI-derived DOI for lymph node metastasis.

PATIENTS AND METHODS

In a retrospective analysis, 156 patients with newly diagnosed tongue cancer were included. Tumour's DOI was compared between MRI measurement and pathology by Pearson correlation coefficient and paired t test. The accuracy of MRI-derived DOI was compared to the pathological DOI. The relationship between MRI-derived DOI and cervical lymph node metastasis was calculated by receiver operating characteristic curve.

RESULTS

Tumour's DOI was well correlated between MRI measurement and pathology with correlation coefficients of 0.77. MRI-derived DOI was 3.4 mm (28%) larger than pathology. The accuracy of MRI in deciding pathological DOI was 67.9%. The cut-off value of MRI-derived DOI was 10.5 mm for lymph node metastasis of tongue cancer.

CONCLUSION

Magnetic resonance imaging can be used as a reference to determine tumour's DOI of tongue cancer. Tumour with MRI-derived DOI larger than 10.5 mm deserves simultaneous neck dissection at initial surgery.

Assessment of tumour depth in early tongue cancer: Accuracy of MRI and intraoral ultrasound

OBJECTIVES

Complete resection of tongue cancer is necessary to achieve local control. Unfortunately, deep resection margins are frequently inadequate. To improve deep margin control, accurate knowledge of tumour thickness is pivotal. Magnetic resonance imaging (MRI) and intraoral ultrasound (ioUS) are frequently applied for tumour staging. This study explores the accuracy of these techniques to estimate depth of invasion.

MATERIALS AND METHODS

The data of patients with a T1-2 tongue cancer that had been treated surgically between 2014 and 2018 were retrospectively analysed. Measurements that had been taken by either MRI or ioUS were compared with those taken during histopathology.

RESULTS

A total of 83 patients with tongue cancer had undergone a pre-operative MRI and 107 had been studied through an ioUS. Tumour thickness measured by MRI (r = 0.72) and ioUS (r = 0.78) correlated significantly (p < 0.001) with histopathological depth of invasion (DOI). In tumours with a DOI of 0-10 mm, MRI has a mean absolute difference with histopathology of 3.1 mm (SD 3.2 mm) and ioUS of 1.6 mm (SD 1.3 mm). In tumours with a DOI greater than 10 mm, MRI has a mean absolute difference of 3.5 mm (SD 3.0 mm) and ioUS of 4.7 mm (SD 3.5 mm).

CONCLUSION

Estimation of histopathological DOI in tongue cancers with DOI till 10 mm is very accurate through use of ioUS. ioUS tends to underestimate DOI in tumors exceeding 10 mm DOI. MRI tends to overestimate DOI in both thin and thick tumours. Since ultrasound measurements can be performed during surgery, ioUS could potentially guide the surgeon in the achievement of adequate resection margins.

A critical evaluation of computed tomography-derived depth of invasion in the preoperative assessment of oral cancer staging

BACKGROUND

Depth of invasion (DOI) has been introduced into the latest TNM classification of oral squamous cell carcinoma (OSCC). Despite its primarily pathological definition (pDOI), a preoperative evaluation of a radiological DOI (rDOI) would be useful but a standard and practical definition is lacking. The primary aim of this study is to measure the rDOI by computed tomography (CT) and compare it to the pDOI in a cohort of OSCC patients. Then, we analyze the utility and reliability of rDOI in the preoperative setting.

METHODS

58 cases of OSCC operated at our Institution from 2016 to 2019 were included. After accounting for plane-specific shrinkage factors and for different oral subsites, we have compared pDOI and rDOI for each spatial plane by paired difference test and correlation coefficient. Radiological accuracy and survival analysis were also determined to identify rDOI's clinical value.

RESULTS

For lateral tongue, pDOI was more strongly related with axial rDOI (P < 0.01); for hard palate, the best plane was the sagittal one (P < 0.01); in floor of mouth (FOM) lesions, the strongest correlation was with coronal rDOI (P < 0.01), as well as for cheek buccal mucosa; sagittal scans seem to be the best to evaluate dorsum of the tongue and retromolar trigone; gingiva (P < 0.01) was most correctly evaluated in the coronal plane. Overall accuracy of rDOI restaging was 75.41%. Disease-free survival seems to be worse as rDOI increases.

CONCLUSIONS

We suggest that with a standardized imaging protocol patients could be better classified according to CT-derived DOI.

Radiological approach for the newly incorporated T staging factor, depth of invasion (DOI), of the oral tongue cancer in the 8th edition of American Joint Committee on Cancer (AJCC) staging manual: assessment of the necessity for elective neck dissection

The 8^th edition of American Joint Committee on Cancer's (AJCC) Cancer Staging Manual was modified by incorporating depth of invasion (DOI) in the T categorization of oral cavity cancer. This is because DOI is strongly associated with cervical lymph node metastasis, which is the most important negative prognostic factor of oral cavity cancer. This major change in the AJCC Cancer Staging Manual caused re-staging of T category in several cases. Although, the DOI on MRI and CT (radiological DOI; r-DOI) strongly correlated with pathological DOI (p-DOI), it is often 2-3 mm larger than p-DOI. Due to this variance, estimation of p-DOI based on r-DOI may not be accurate. However, when a lesion is undetectable on MRI, p-DOI was often smaller than 4 mm. On the other hand, when MRI depicts lesions with styloglossus and hyoglossus muscle invasion, p-DOI was always larger than 4 mm. These correlations between MRI findings and p-DOI are important when assessing the need for elective neck dissection, as the National Comprehensive Cancer Network (NCCN) recommends elective neck dissection in cases with DOI greater than 4 mm.

New AJCC: How does it impact oral cancers?

PURPOSE OF REVIEW

The objective of this article is to critically review the rationale for the changes in the staging of the oral cavity cancers.

RECENT FINDINGS

After reviewing many recent studies about oral cancer and analyzing multi-institutional data for outcomes, the staging system was updated to include new knowledge of the disease and its biological behavior.

SUMMARY

This article reviews the changes in the staging of oral cavity cancers published in the 8th edition of the AJCC/UICC TNM cancer staging manual and discusses future directions.

Imaging in oral cancers: A comprehensive review

This review aims at simplifying the relevant imaging anatomy, guiding the optimal imaging method and highlighting the key imaging findings that influence prognosis and management of oral cavity squamous cell carcinoma (OSCC). Early OSCC can be treated with either surgery alone while advanced cancers are treated with a combination of surgery, radiotherapy and/or chemotherapy. Considering the complex anatomy of the oral cavity and its surrounding structures, imaging plays an indispensable role not only in locoregional staging but also in the distant metastatic work-up and post treatment follow-up. Knowledge of the anatomy with understanding of common routes of spread of cancer, allows the radiologist to accurately determine disease extent and augment clinical findings to plan appropriate therapy. This review aims at simplifying the relevant imaging anatomy, guiding the optimal imaging method and highlighting the key imaging findings that influence prognosis and management.

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

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.

Quantification of structural and microvascular changes for diagnosing early-stage oral cancer

Changes in mucosal microvascular networks, called intraepithelial papillary capillary loops (IPCL), are an important key factor for diagnosing early-stage oral cancer in vivo. Nevertheless, there are a lack of tools to quantify these changes objectively. This is the first study to quantify the IPCL changes in vivo to differentiate benign or malignant oral lesions by the optical coherence tomography (OCT) technique. K14-EGFP-miR-211-GFP transgenic mice were inducted by 4-Nitroquinoline-1-oxide to produce oral carcinogenesis in different stages, including normal, premalignancy and cancer. The results showed significant differentiation between benign or malignant lesions by OCT quantitative parameters, including epithelial thickness, IPCL density, radius and tortuosity.

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

Background

The 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 nodal metastasis and an independent prognostic factor. Although the histopathological definition of depth of invasion is clear, an accurate method for its radiological assessment has not yet been validated.

Purpose

To investigate the role of MRI-derived depth of invasion evaluation in staging oral tongue squamous cell carcinoma and to assess the inter-reader agreement and the radiological–pathological correlation.

Material and Methods

We retrospectively reviewed 43 patients with oral tongue squamous cell carcinoma who underwent preoperative MRI. The MRI-derived depth of invasion was measured by two radiologists, each with a different degree of experience in head and neck imaging. The pathological depth of invasion was recorded from histopathological reports. The inter-reader and the radiological–histopathological correlations for the depth of invasion were evaluated with Bland–Altman plots, the intraclass correlation coefficients (ICC), and the paired samples test; agreements for T staging were assessed using the Kappa coefficient.

Results

Inter-reader reliability was excellent for the MRI-derived depth of invasion (ICC = 0.91), very good between MRI-derived depth of invasion and pathological depth of invasion (ICC = 0.89 for the experienced reader, 0.86 for the inexperienced reader). Both readers reached a good agreement regarding T staging (kappa value = 0.70). Furthermore, the agreement between radiological and pathological T staging was good (kappa value = 0.74 for the experienced reader, 0.60 for the inexperienced reader).

Conclusion

MRI-derived depth of invasion should be measured in the pretreatment assessment of oral tongue squamous cell carcinoma as it has an excellent inter-reader reliability and nearly excellent radiological–pathological correlation.

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

OBJECTIVES

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).

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.