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

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.

The prognostic role of single cell invasion and nuclear diameter in early oral tongue squamous cell carcinoma

BACKGROUND

The clinical significance of single cell invasion and large nuclear diameter is not well documented in early-stage oral tongue squamous cell carcinoma (OTSCC).

METHODS

We used hematoxylin and eosin-stained sections to evaluate the presence of single cell invasion and large nuclei in a multicenter cohort of 311 cases treated for early-stage OTSCC.

RESULTS

Single cell invasion was associated in multivariable analysis with poor disease-specific survival (DSS) with a hazard ratio (HR) of 2.089 (95% CI 1.224-3.566, P = 0.007), as well as with disease-free survival (DFS) with a HR of 1.666 (95% CI 1.080-2.571, P = 0.021). Furthermore, large nuclei were associated with worse DSS (HR 2.070, 95% CI 1.216-3.523, P = 0.007) and with DFS in multivariable analysis (HR 1.645, 95% CI 1.067-2.538, P = 0.024).

CONCLUSION

Single cell invasion and large nuclei can be utilized for classifying early OTSCC into risk groups.

Efficacy of radiological depth of invasion measurements on magnetic resonance images acquired at different magnetic field strengths and imaging sequences in predicting cervical lymph node metastasis and other outcomes in tongue cancer

OBJECTIVES

We investigated the correlation between magnetic resonance imaging (MRI) parameters and tumor pathological depth of invasion (pDOI), between pDOI and radiological DOI (rDOI), between rDOI and duration between biopsy and MRI, and between rDOI and duration between MRI and surgery to determine the efficacy of rDOI in identifying small lesions and other conditions.

STUDY DESIGN

We examined 36 adult patients who had been diagnosed histopathologically with cancer of the tongue and had undergone a glossectomy. Using 1.5 Tesla (T) and 3.0T MRI, we measured rDOI at the deepest infiltration point on 4 MRI sequences. We calculated the correlations between rDOI and the variables examined by Spearman rho analysis and evaluated the diagnostic performance of rDOI by receiver operating characteristic curve analysis.

RESULTS

Axial T2-weighted images using 1.5T MRI provided the closest approximation of pDOI. Although the correlation between rDOI and pDOI was significant, rDOI showed poor or acceptable discrimination in identifying small lesions and other conditions. There were no significant correlations between rDOI and the time between biopsy and MRI or between MRI and surgery.

CONCLUSIONS

The correlation between rDOI and pDOI is significant, but rDOI is ineffective in predicting malignancy and other conditions. Axial T2-weighted images using 1.5T MRI provide the closest approximation of pDOI.

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.

Preoperative Determination of Depth of Invasion in Oral Cavity Squamous Cell Carcinoma by Standard Cross-Sectional Imaging With Computed Tomography and Positron Emission Tomography/Computed Tomography

Background Depth of invasion (DOI) is a known indicator of metastatic potential in oral cavity squamous cell carcinoma (SCC). Our purpose was to investigate the accuracy of preoperative determination of DOI in oral cavity SCC by computed tomography (CT) and positron emission tomography/computed tomography (PET/CT). Methodology A retrospective study was performed using consecutive patients with histologically proven oral cavity SCC presenting to our otorhinolaryngology department between January 2014 and July 2019 who underwent preoperative contrast-enhanced CT and/or PET/CT. Pathological assessment of DOI was determined by a review of pathology reports. The degree of DOI determined by radiographic studies was correlated to pathology results. Results A total of 79 patients were screened of whom appropriate radiographic studies were available for 63 patients. The mean DOI by pathological assessment was 12.3 ± 9.1 mm. CT and PET/CT determined depth both correlated with pathological DOI (r = 0.710; p < 0.001, r = 0.798; p < 0.001). No significant correlation was seen for CT-determined depth (r = 0.136; p = 0.709) or PET-determined depth (r = 0.234; p = 0.707) with pathologically confirmed superficial tumors (<5 mm). For patients with pathological tumor depth >10 mm, CT and PET determined depth both correlated with pathological depth (r = 0.577; p = 0.002, r = 0.668; p = 0.001). The sensitivity and specificity of CT and PET for the identification of deep invasion were 88.2% and 41.7% and 52.9% and 50%, respectively. Conclusions DOI measurement is feasible with routine preoperative CT and PET/CT images and is comparable to pathological measurement in patients with oral cavity SCC.

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.

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.

Diagnostic and prognostic value of magnetic resonance imaging in the detection of tumor depth of invasion and bone invasion in patients with oral cavity cancer

PURPOSE

To evaluate the accuracy of preoperative contrast-enhanced magnetic resonance imaging (MRI) in the assessment of radiological depth of invasion (rDOI) and bone invasion in patients with oral cavity cancer, and the prognostic value of preoperative rDOI.

MATERIALS AND METHODS

This retrospective study included patients with surgically resected oral cavity cancer and preoperative MRI acquired within four weeks before surgery. Two readers evaluated the MRI to assess the superficial and deep bone invasion, preoperative T stage, and measured the rDOI. The rDOI was compared to the histopathological DOI (pDOI), used as reference standard. Prognostic value of preoperative features for the disease-specific survival was evaluated using the Kaplan-Meier curve and multivariable Cox proportional hazards analysis.

RESULTS

The final population included 80 patients (50 males, mean age 67.7 ± 13.6 years). There was a strong statistically significant correlation between the rDOI (median 10 mm) and the pDOI (median 9 mm) (ρ: 0.978, p < 0.001). The agreement between MRI and histopathological T stage was excellent (k = 0.93, 95% CI 0.86, 0.99). The sensitivity and specificity of preoperative MRI were 93.3% and 98.8% for deep bone invasion, while they were 75.0% and 95.8% for superficial bone invasion, respectively. The rDOI > 10 mm was associated with poorer disease-specific survival (log-rank p = 0.016). The rDOI remained the only independent preoperative predictor associated with poorer disease-specific survival at multivariable analysis (hazard ratio 5.5; 95% CI 1.14, 26.58; p = 0.033).

CONCLUSION

Preoperative MRI is accurate for the assessment of DOI and bone invasion. The rDOI is an independent preoperative predictor of disease-specific survival in patients with oral cavity cancer.

Neck Management in cT1N0 Tongue Squamous Cell Carcinoma as Determined by Sonographic Depth of Invasion

Objectives

To compare the oncologic outcomes in patients with cT1N0 tongue squamous cell carcinoma (SCC) who underwent different neck management strategies stratified by sonographic depth of invasion (DOI).

Methods

The included patients were retrospectively enrolled, and divided into two groups: observation (OBS) and elective neck dissection (END). The regional control (RC) and disease-specific survival (DSS) rates were compared and stratified by sonographic DOI.

Results

The mean sonographic and pathologic DOIs were 3.8 and 3.7 mm, respectively; the two DOIs were significantly correlated (Spearman correlation coefficient 0.974. p <0.001). In patients with sonographic DOI <4.0 mm, the 5-year RC rates were 73 and 89% in the OBS and END groups, respectively, and were not significantly different. However, in patients with sonographic DOI ≥4.0 mm, the 5-year RC rate was significantly different between the OBS (57%) and END (80%) groups (p = 0.031). In patients with sonographic DOI <4.0 mm, the 5-year DSS rates were 79 and 89% in OBS and END groups, respectively, and were not significantly different. However, in patients with sonographic DOI ≥4.0 mm, the 5-year DSS rate was significantly different between the OBS (67%) and END (86%) groups (p = 0.033).

Conclusions

Sonographic DOI was notably correlated with pathologic DOI. Moreover, there was a significant survival difference between the OBS and END groups in cT1N0 tongue SCC patients with sonographic DOI ≥4.0 mm but not in those with sonographic DOI <4.0 mm. Our study provides a useful method to aid decision-making in the clinical setting for this patient group.

MRI before biopsy correlates with depth of invasion corrected for shrinkage rate of the histopathological specimen in tongue carcinoma

The purpose of this study was to evaluate which radiological depth of invasion (r-DOI) measurement is the most concordant to clinical DOI (c-DOI) derived from correction for the shrinkage rate of the histopathological specimens. We retrospectively reviewed 128 patients with tongue carcinoma who had undergone glossectomy between 2006 and 2019. At first, the width shrinkage rate during formalin fixation and preparation process of histopathological specimens was evaluated. From the shrinking rates, a formula to calculate c-DOI from pathological DOI (p-DOI) was developed. The correlation between c-DOI and r-DOI was evaluated. The specimen shrinkage rate during the histopathological specimen preparation process was 10.3%. Based on that, we yielded the correct formula for c-DOI based on p-DOI and preparation shrinkage rate: c-DOI = p-DOI × 100/89.7. The regression equations for the association of c-DOI with r-DOI measured by ultrasound (n = 128), MRI before biopsy (n = 18), and MRI after biopsy (n = 110) were y = 1.12 * x + 0.21, y = 0.89 * x − 0.26, and y = 0.52 * x + 2.63, respectively, while the coefficients of determination were 0.664, 0.891, and 0.422, respectively. In conclusion, r-DOI using MRI before biopsy most strongly correlated with c-DOI.

Histogram analysis of diffusion-weighted imaging and dynamic contrast-enhanced MRI for predicting occult lymph node metastasis in early-stage oral tongue squamous cell carcinoma

OBJECTIVES

To investigate the feasibility of whole-tumor histogram analysis of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) MRI for predicting occult lymph node metastasis (LNM) in early-stage oral tongue squamous cell cancer (OTSCC).

MATERIALS AND METHODS

This retrospective study included 55 early-stage OTSCC (cT1-2N0M0) patients; 34 with pathological LNM and 21 without. Eight whole-tumor histogram features were extracted from quantitative apparent diffusion coefficient (ADC) maps and two semi-quantitative DCE parametric maps (wash-in and wash-out). The clinicopathological factors and histogram features were compared between the two groups. Stepwise logistic regression was used to identify independent predictors. Receiver operating characteristic curves were generated to assess the performances of significant variables and a combined model for predicting occult LNM.

RESULTS

MRI-determined depth of invasion and ADC_entropy was significantly higher in the LNM group, with respective areas under the curve (AUCs) of 0.67 and 0.69, and accuracies of 0.73 and 0.73. ADC_10th. ADC_uniformity and wash-in_skewness were significantly lower in the LNM group, with respective AUCs of 0.68, 0.71, and 0.69, and accuracies of 0.65, 0.71, and 0.64. Histogram features from wash-out maps were not significantly associated with cervical node status. In the logistic regression analysis, ADC_10th, ADC_uniformity, and wash-in_skewness were independent predictors. The combined model yielded the best predictive performance, with an AUC of 0.87 and an accuracy of 0.82.

CONCLUSIONS

Whole-tumor histogram analysis of ADC and wash-in maps is a feasible tool for preoperative evaluation of cervical node status in early-stage OTSCC.

KEY POINTS

• Histogram analysis of parametric maps from DWI and DCE-MRI may assist the prediction of occult LNM in early-stage OTSCC. • ADC_10th, ADC_uniformity, and wash-in_skewness were independent predictors. • The combined model exhibited good predictive performance, with an accuracy of 0.82.

The prognostic role of the pre-treatment neutrophil to lymphocyte ratio (NLR) and tumor depth of invasion (DOI) in early-stage squamous cell carcinomas of the oral tongue

The appropriate surgical management of early-stage oral tongue squamous cell carcinoma (OTSCC) remains a debated topic. The aim of this study is to investigate the role of the pre-treatment neutrophil to lymphocyte ratio (NLR) and tumor depth of invasion (DOI) in predicting the presence of occult neck metastases in early-stage OTSCC. A retrospective analysis of patients affected by early-stage (cT1-T2 cN0) OTSCC who were submitted to elective neck dissection (END) was performed. Tumors were classified retrospectively according to the 8th TNM classification, the DOI was assessed on the pre-operative magnetic resonance imaging, and the pre-treatment NLR was calculated for each patient. A logistic regression model to estimate the probability π (x) of cervical metastases by studying the NLR and DOI was carried out. Next, the correlation between the two variables, the NLR and DOI, was preliminarily studied. A cohort of 110 patients was analyzed (mean age, 62 years old; male to female ratio 1.2:1). The patients were staged as cT1 in 53 cases and cT2 in 57 cases. A DOI greater than 5.4 mm and a NLR greater than 2.93 are associated with an increased risk of presenting occult cervical metastases. Furthermore, the variables NLR and DOI are linearly associated with a positive correlation, proved by Spearman's rank correlation coefficient rho of 0.64, with a unitary increase in the DOI of 1 mm directly associated with an increase of 0.47 in the NLR. The DOI and NLR can be effectively used to predict the occurrence of occult neck metastasis and therefore to plan an END in early-stage OTSCC.

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.

The Potential of MET Immunoreactivity for Prediction of Lymph Node Metastasis in Early Oral Tongue Squamous Cell Carcinoma

Objective

MET positivity is independently associated with survival in oral squamous cell carcinoma (OSCC). Since MET is a known orchestrator of invasive tumor growth, we investigated its association with LNM in early oral tongue squamous cell carcinoma (OTSCC). As it is recommended by the NCCN to use tumor depth of invasion (DOI) in making decisions on elective neck dissection (END), the results obtained for MET positivity were aligned with those for DOI > 4 mm. The cutoff value used in our institution.

Methods

Tumor samples from patients who underwent primary tumor resection and neck dissection between 1995 and 2013, were collected from the archives of the Leiden and Erasmus University Medical Center. Immunohistochemistry with D1C2 was performed to identify MET negative (< 10% uniform positivity) and MET positive (≥ 10% uniform positivity) cancers. ROC curve analysis and the Chi-squared test were used to investigate the association of MET positivity with LNM (pN+ and occult). Binary logistic regression was used to investigate the association of MET positivity with LNM.

Results

Forty-five (44.1%) of the 102 cancers were MET positive. Ninety were cN0 of which 20 were pN+ (occult metastasis). The remaining 12 cancers were cN+, of which 10 were proven pN+ and 2 were pN0. MET positivity was associated with LNM with a positive predictive value (PPV) of 44.4% and a negative predictive value (NPV) of 82.5% for pN+. For the occult group, the PPV was 36.8% and the NPV was 88.5%. Regression analysis showed that MET positivity is associated with pN+ and occult LNM (p-value < 0.05).

Conclusion

MET positivity is significantly associated with LNM in early OTSCC, outperforming DOI. The added value of MET positivity could be in the preoperative setting when END is being considered during the initial surgery. For cases with DOI ≤ 4 mm, MET positivity could aid in the clinical decision whether regular follow-up, watchful waiting, or END is more appropriate. Realizing that these preliminary results need to be independently validated in a larger patient cohort, we believe that MET positivity could be of added value in the decision making on END in early OTSCC.

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.

Variability in Recommendations for Cervical Lymph Node Pathology for Staging of Canine Oral Neoplasia: A Survey Study

There is no clear guideline regarding the indication for routine lymph node extirpation and pathologic evaluation during staging of canine oral tumors, despite a relatively high reported nodal metastatic rate for select tumor types. It is particularly unclear if clinicians recommend removal of lymph nodes only when there is confirmation of metastasis, defined as the N+ neck, or if elective neck dissection (END) is routinely recommended to confirm the true pathologic metastatic status of lymph nodes in the clinical N0 neck (no evidence of metastasis on clinical staging with diagnostic imaging or cytology). When clinicians are recommending END as a staging tool to confirm nodal status, there is also ambiguity regarding the surgical extent for subsequent histopathologic evaluation. The objective of this cross-sectional survey study was to determine the current recommendations given by practicing specialists regarding lymph node removal for dogs with oral tumors. Overall, 87 responses were obtained from 49 private practices (56%) and 38 academic institutions (44%). Respondents identified as oncologists (44%, N = 38), soft tissue surgeons (40%, N = 35), and dentists (16%, N = 14). Regardless of tumor type and stage, extirpation and histopathology were most commonly recommended in the clinical N+ neck only. The recommendation to routinely perform END in the N0 neck was significantly associated with tumor type. Bilateral removal of the mandibular and retropharyngeal lymph nodes was recommended more often for oral malignant melanoma (OMM) than for oral squamous cell carcinoma (OSCC; p ≤ 0.0039) or for oral fibrosarcoma (OFSA; p ≤ 0.0007). The likelihood of recommending END increased with increasing tumor size. Academic clinicians were significantly (p < 0.01) more likely to recommend END compared to private practitioners for canine T1-T3 OMM, T3 OSCC, T2 OFSA, and MCT. This study highlights the variability in recommendations for lymph node pathology for dogs with oral tumors. While tumor type and size influenced the decision to pursue END, it was not routinely recommended, even for tumor types with a known propensity for metastasis. Prospective studies are warranted to determine the potential diagnostic and therapeutic value of END in the N0 neck in veterinary patients such that a consensus approach can be made.

Depth of invasion in early stage oral cavity squamous cell carcinoma: The optimal cut-off value for elective neck dissection

OBJECTIVES

Depth of invasion (DOI) is the most important predictor for lymph node metastasis (LNM) in early stage (T1-T2) oral cancer. The aim of this study is to validate the cut-off value of 4 mm on which the decision to perform an Elective Neck Dissection (END) is made.

MATERIALS AND METHODS

We performed a retrospective study in patients with pathologically proven early stage oral cavity squamous cell carcinoma (OCSCC) without clinical or radiological signs of LNM, who were treated between 2013 and 2018. An END was performed when DOI was ≥ 4 mm and a watchful waiting protocol was applied in patients with DOI < 4 mm.

RESULTS

Three hundred patients were included. END was performed in 77% of patients with DOI ≥ 4 mm, of which 36% had occult LNM (pN+). Patients in the watchful waiting group (48%) developed a regional recurrence in 5.2% for DOI < 4 mm and 24.1% for DOI ≥ 4 mm. For DOI ≥ 4 mm, regional recurrence free survival was higher for patients who were treated with END compared to watchful waiting (p = 0.002). A Receiver-Operator-Curve -analysis showed that a DOI cut-off value of 4.0 mm was the optimal threshold for the prediction of occult LNM (95.1% sensitivity, 52.9% specificity).

CONCLUSION

A DOI of ≥ 4 mm is an accurate cut-off value for performing an END in early stage OCSCC. END results in higher survival rates and lower regional recurrence rates in patients with DOI ≥ 4 mm.